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Calcium Score Improves Framingham Algorithm : An elevated calcium score corresponded to a significantly increased risk of events.
CHICAGO — The Framingham Heart Study risk algorithm fails to identify a significant number of individuals at high risk of coronary heart disease, and its accuracy could be improved significantly by integrating coronary calcium scoring, according to a new study from the Netherlands.
“Coronary calcium scoring, detected by computed tomography, is a promising way to improve cardiovascular risk prediction. Population-based studies have shown that the calcium score is a strong predictor of coronary events,” said Rozemarijn Vliegenthart Proença, Ph.D., of University Medical Center Groningen (the Netherlands).
This 7-year-long study of 2,038 patients, conducted at the medical center, is supported by outcomes data demonstrating that nearly two-thirds of patients who would be classified as intermediate risk should actually be reclassified as having either high or low risk. Dr. Vliegenthart Proença presented the data here at the annual meeting of the Radiological Society of North America.
The study questioned whether adding the calcium score to known cardiovascular risk factors would actually improve risk classification in the population.
The imaging analysis was embedded into the population-based Rotterdam Study, and 2,038 individuals aged 55–85 years were invited to participate.
“We assessed as clinical outcome coronary heart disease comprising nonfatal myocardial infarction, [coronary heart disease] mortality, coronary artery bypass grafting, and percutaneous coronary interventions,” Dr. Vliegenthart Proença said. Coronary calcification was measured by electron beam tomography, and Agatson's method was used to calculate calcium scores.
Investigators created two prediction models: one with variables of the Framingham risk score, fitted to this patient population, and the other including the calcium score. Risk estimates for coronary events were extrapolated to 10 years, the common time horizon for predicting cardiovascular risk.
“Then we calculated reclassification percentages to assess what the actual effect is of adding the calcium score to risk factors. Finally we compared the predicted risk, in the different categories, to the actually observed risk,” Dr. Vliegenthart Proença said.
Patients had a mean age of 70 years, and 1,171 (57%) were women. During the course of the study, 84 men and 45 women had a coronary event.
An elevated calcium score corresponded to significantly increased risk of events. Men with a calcium score over 400 had a sevenfold increased risk, compared with men who had a calcium score of 0–10. “When we adjusted for cardiovascular risk factors, these relative risks did not materially change,” Dr. Vliegenthart Proença said.
The strong association between the amount of coronary calcification and the risk of coronary heart disease was evident in the women's cohort as well.
When the calcium score was included with the Framingham risk score, almost 30% migrated to different risk categories. Reclassification was most prominent in the intermediate Framingham risk category, where nearly two-thirds of men and women were reclassified as either lower or higher risk.
According to Dr. Vliegenthart Proença, this was one of the study's strengths.
“Reclassification was based on the actual events. The observed risk in the different categories were calculated on the basis of our risk model, our prediction model, and on the basis of the actual events occurring in the different risk categories.”
An audience member questioned whether the Netherlands has used this data to change treatment recommendations.
“Actually, that is work in progress. At this moment there is no screening for coronary calcium in the Dutch population,” Dr. Vliegenthart Proença explained.
Session moderator Dr. Frank John Rybicki III of Harvard Medical School, Boston, agreed.
“This was an important study because it used actual patient outcomes with a follow-up of almost 7 years to then reclassify risk, integrating calcium score into the traditional methods of risk, which is the Framingham model. And it showed with outcomes that there is a positive influence integrating calcium with those more traditional risk factors. It pretty specifically shows that integration of the calcium score has a very high chance of being beneficial in determining one's overall risk.”
In a separate presentation, Dr. Vliegenthart Proença argued for noninvasive cardiac imaging of asymptomatic patients with peripheral arterial disease. A randomized, controlled trial of 231 such patients at her institution found that one in five were indicated for coronary revascularization.
Dr. Rybicki did not find this surprising. “A fifth of patients with peripheral arterial disease are also going to have significant coronary disease. We expect that. The main finding that 20% of those patients actually have severe coronary disease is interesting and important to demonstrate, but not particularly surprising.”
The studies were sponsored by University Medical Center Groningen.
Dr. Vliegenthart Proença reported having no potential inancial conflicts of interest.
Including the calcium score moved 30% of patients to different risk categories.
Source DR. VLIEGENTHART PROENÇA
CHICAGO — The Framingham Heart Study risk algorithm fails to identify a significant number of individuals at high risk of coronary heart disease, and its accuracy could be improved significantly by integrating coronary calcium scoring, according to a new study from the Netherlands.
“Coronary calcium scoring, detected by computed tomography, is a promising way to improve cardiovascular risk prediction. Population-based studies have shown that the calcium score is a strong predictor of coronary events,” said Rozemarijn Vliegenthart Proença, Ph.D., of University Medical Center Groningen (the Netherlands).
This 7-year-long study of 2,038 patients, conducted at the medical center, is supported by outcomes data demonstrating that nearly two-thirds of patients who would be classified as intermediate risk should actually be reclassified as having either high or low risk. Dr. Vliegenthart Proença presented the data here at the annual meeting of the Radiological Society of North America.
The study questioned whether adding the calcium score to known cardiovascular risk factors would actually improve risk classification in the population.
The imaging analysis was embedded into the population-based Rotterdam Study, and 2,038 individuals aged 55–85 years were invited to participate.
“We assessed as clinical outcome coronary heart disease comprising nonfatal myocardial infarction, [coronary heart disease] mortality, coronary artery bypass grafting, and percutaneous coronary interventions,” Dr. Vliegenthart Proença said. Coronary calcification was measured by electron beam tomography, and Agatson's method was used to calculate calcium scores.
Investigators created two prediction models: one with variables of the Framingham risk score, fitted to this patient population, and the other including the calcium score. Risk estimates for coronary events were extrapolated to 10 years, the common time horizon for predicting cardiovascular risk.
“Then we calculated reclassification percentages to assess what the actual effect is of adding the calcium score to risk factors. Finally we compared the predicted risk, in the different categories, to the actually observed risk,” Dr. Vliegenthart Proença said.
Patients had a mean age of 70 years, and 1,171 (57%) were women. During the course of the study, 84 men and 45 women had a coronary event.
An elevated calcium score corresponded to significantly increased risk of events. Men with a calcium score over 400 had a sevenfold increased risk, compared with men who had a calcium score of 0–10. “When we adjusted for cardiovascular risk factors, these relative risks did not materially change,” Dr. Vliegenthart Proença said.
The strong association between the amount of coronary calcification and the risk of coronary heart disease was evident in the women's cohort as well.
When the calcium score was included with the Framingham risk score, almost 30% migrated to different risk categories. Reclassification was most prominent in the intermediate Framingham risk category, where nearly two-thirds of men and women were reclassified as either lower or higher risk.
According to Dr. Vliegenthart Proença, this was one of the study's strengths.
“Reclassification was based on the actual events. The observed risk in the different categories were calculated on the basis of our risk model, our prediction model, and on the basis of the actual events occurring in the different risk categories.”
An audience member questioned whether the Netherlands has used this data to change treatment recommendations.
“Actually, that is work in progress. At this moment there is no screening for coronary calcium in the Dutch population,” Dr. Vliegenthart Proença explained.
Session moderator Dr. Frank John Rybicki III of Harvard Medical School, Boston, agreed.
“This was an important study because it used actual patient outcomes with a follow-up of almost 7 years to then reclassify risk, integrating calcium score into the traditional methods of risk, which is the Framingham model. And it showed with outcomes that there is a positive influence integrating calcium with those more traditional risk factors. It pretty specifically shows that integration of the calcium score has a very high chance of being beneficial in determining one's overall risk.”
In a separate presentation, Dr. Vliegenthart Proença argued for noninvasive cardiac imaging of asymptomatic patients with peripheral arterial disease. A randomized, controlled trial of 231 such patients at her institution found that one in five were indicated for coronary revascularization.
Dr. Rybicki did not find this surprising. “A fifth of patients with peripheral arterial disease are also going to have significant coronary disease. We expect that. The main finding that 20% of those patients actually have severe coronary disease is interesting and important to demonstrate, but not particularly surprising.”
The studies were sponsored by University Medical Center Groningen.
Dr. Vliegenthart Proença reported having no potential inancial conflicts of interest.
Including the calcium score moved 30% of patients to different risk categories.
Source DR. VLIEGENTHART PROENÇA
CHICAGO — The Framingham Heart Study risk algorithm fails to identify a significant number of individuals at high risk of coronary heart disease, and its accuracy could be improved significantly by integrating coronary calcium scoring, according to a new study from the Netherlands.
“Coronary calcium scoring, detected by computed tomography, is a promising way to improve cardiovascular risk prediction. Population-based studies have shown that the calcium score is a strong predictor of coronary events,” said Rozemarijn Vliegenthart Proença, Ph.D., of University Medical Center Groningen (the Netherlands).
This 7-year-long study of 2,038 patients, conducted at the medical center, is supported by outcomes data demonstrating that nearly two-thirds of patients who would be classified as intermediate risk should actually be reclassified as having either high or low risk. Dr. Vliegenthart Proença presented the data here at the annual meeting of the Radiological Society of North America.
The study questioned whether adding the calcium score to known cardiovascular risk factors would actually improve risk classification in the population.
The imaging analysis was embedded into the population-based Rotterdam Study, and 2,038 individuals aged 55–85 years were invited to participate.
“We assessed as clinical outcome coronary heart disease comprising nonfatal myocardial infarction, [coronary heart disease] mortality, coronary artery bypass grafting, and percutaneous coronary interventions,” Dr. Vliegenthart Proença said. Coronary calcification was measured by electron beam tomography, and Agatson's method was used to calculate calcium scores.
Investigators created two prediction models: one with variables of the Framingham risk score, fitted to this patient population, and the other including the calcium score. Risk estimates for coronary events were extrapolated to 10 years, the common time horizon for predicting cardiovascular risk.
“Then we calculated reclassification percentages to assess what the actual effect is of adding the calcium score to risk factors. Finally we compared the predicted risk, in the different categories, to the actually observed risk,” Dr. Vliegenthart Proença said.
Patients had a mean age of 70 years, and 1,171 (57%) were women. During the course of the study, 84 men and 45 women had a coronary event.
An elevated calcium score corresponded to significantly increased risk of events. Men with a calcium score over 400 had a sevenfold increased risk, compared with men who had a calcium score of 0–10. “When we adjusted for cardiovascular risk factors, these relative risks did not materially change,” Dr. Vliegenthart Proença said.
The strong association between the amount of coronary calcification and the risk of coronary heart disease was evident in the women's cohort as well.
When the calcium score was included with the Framingham risk score, almost 30% migrated to different risk categories. Reclassification was most prominent in the intermediate Framingham risk category, where nearly two-thirds of men and women were reclassified as either lower or higher risk.
According to Dr. Vliegenthart Proença, this was one of the study's strengths.
“Reclassification was based on the actual events. The observed risk in the different categories were calculated on the basis of our risk model, our prediction model, and on the basis of the actual events occurring in the different risk categories.”
An audience member questioned whether the Netherlands has used this data to change treatment recommendations.
“Actually, that is work in progress. At this moment there is no screening for coronary calcium in the Dutch population,” Dr. Vliegenthart Proença explained.
Session moderator Dr. Frank John Rybicki III of Harvard Medical School, Boston, agreed.
“This was an important study because it used actual patient outcomes with a follow-up of almost 7 years to then reclassify risk, integrating calcium score into the traditional methods of risk, which is the Framingham model. And it showed with outcomes that there is a positive influence integrating calcium with those more traditional risk factors. It pretty specifically shows that integration of the calcium score has a very high chance of being beneficial in determining one's overall risk.”
In a separate presentation, Dr. Vliegenthart Proença argued for noninvasive cardiac imaging of asymptomatic patients with peripheral arterial disease. A randomized, controlled trial of 231 such patients at her institution found that one in five were indicated for coronary revascularization.
Dr. Rybicki did not find this surprising. “A fifth of patients with peripheral arterial disease are also going to have significant coronary disease. We expect that. The main finding that 20% of those patients actually have severe coronary disease is interesting and important to demonstrate, but not particularly surprising.”
The studies were sponsored by University Medical Center Groningen.
Dr. Vliegenthart Proença reported having no potential inancial conflicts of interest.
Including the calcium score moved 30% of patients to different risk categories.
Source DR. VLIEGENTHART PROENÇA
Abdominal pain in a 20-year-old woman
A 20-year-old woman presents to the emergency department with postprandial epigastric and right-upper-quadrant pain, sometimes associated with nausea. She has been having six to eight loose bowel movements every day, with no blood or mucus, and she has lost about 20 lb despite a good appetite. The diarrhea did not improve when she tried omitting milk products and carbohydrates.
Her symptoms began several months ago, but she says that 3 days ago the pain worsened steadily, radiating to the middle of her back, with associated episodes of nonbloody, nonbilious emesis. She cannot keep down liquids or solids. She says she has never had such episodes in the past.
She reports no oral ulcers, urinary symptoms, skin rashes, musculoskeletal pain, or neurologic symptoms, and she denies being anxious or depressed.
She has no history of serious illness, surgery, or hospitalization. She smokes a half pack of cigarettes a day, drinks alcohol occasionally, and smokes marijuana occasionally. She is employed as a certified nursing assistant.
She is taking ethinyl estradiol-levonorgestrel pills for birth control and takes calcium carbonate as needed for abdominal discomfort. She is taking no other medications, including nonsteroidal anti-inflammatory drugs (NSAIDs).
Her maternal uncle died of colon cancer at age 32, and her mother had colon polyps on colonoscopy. There is no family history of inflammatory bowel disease or celiac sprue. Her father committed suicide.
Her laboratory values
- White blood cell count 10.2 × 109/L (normal range 4–11)
- Red blood cell count 4.71 × 1012/L (3.9–5.5)
- Hemoglobin 14.4 g/dL (12–16)
- Hematocrit 42.4% (37%–47%)
- Mean corpuscular volume 90 fL (83–99)
- Mean corpuscular hemoglobin 30.6 pg (27–33)
- Platelet count 230 × 109/L (150–400)
- Red cell distribution width 13.3% (11.5%–14.5%)
- Sodium 140 mmol/L (132–148)
- Potassium 3.3 mmol/L (3.5–5.0)
- Chloride 104 mmol/L (98–111)
- Bicarbonate 28 mmol/L (23–32)
- Blood urea nitrogen 9 mg/dL (8–25)
- Creatinine 0.8 mg/dL (0.7–1.4)
- Glucose 87 mg/dL (65–100)
- Alanine aminotransferase 26 U/L (0–45)
- Aspartate aminotransferase 21 U/L (7–40)
- Alkaline phosphatase 101 U/L (40–150)
- Total bilirubin 0.8 mg/dL (0–1.5)
- Albumin 3.5 g/dL (3.5–5)
- Pregnancy screen negative
- Urine toxicology screen negative.
Physical examination
The patient is very thin and appears quite uncomfortable. Her temperature is 99.7°F (37.6°C), pulse rate 101, respiratory rate 18, blood pressure 111/67 mm Hg, and oxygen saturation 96% on room air. Her skin is warm and dry. Her height is 66 inches, weight 116 lb, and body mass index 18.7.
Examination of the head and neck shows normal dentition, dry mucus membranes, and no oral exudates. The thyroid is normal, and no masses or lymphadenopathy are noted.
Heart sounds and rhythm are normal, and the lungs are clear with no crackles or rubs. The abdomen is scaphoid and soft, with no distention. She has epigastric tenderness but no rebound, guarding, rigidity, palpable mass, or costovertebral angle tenderness. Bowel sounds are normal. The neurologic examination is normal.
NARROWING THE DIAGNOSIS
1. Given the history and findings so far, which is the least likely cause of her symptoms?
- Lactose intolerance
- Celiac disease
- Crohn disease
- Duodenal ulcer
- Eating disorder
This young woman’s presentation has some features found in all of these conditions. However, the least likely is lactose intolerance.
Lactose intolerance results from a shortage of the enzyme lactase, which is normally produced by the cells that line the small intestine. Close to 50 million American adults have lactose intolerance. Common symptoms include nausea, cramps, bloating, gas, and diarrhea, which begin about 30 minutes to 2 hours after eating or drinking foods containing lactose.
Since the patient’s symptoms did not improve when she tried omitting milk products, and since lactose intolerance is rarely associated with pain radiating to the back and with severe vomiting, this is the least likely cause of her symptoms.
Celiac disease presents with a myriad of symptoms—sometimes without gastrointestinal (GI) symptoms. Anemia is the most common laboratory finding, due most often to iron deficiency, but also due to deficiencies of vitamin B12 and folate as a result of malabsorption.1
Our patient’s laboratory values—especially her red cell indices—do not confirm this finding. One must also remember, however, that hemoglobin tends to be falsely elevated in patients who are dehydrated.
Crohn disease often presents with occult blood loss, low-grade fever, weight loss, and anemia. Though the condition is most often ileocolic, it can affect any part of the gastrointestinal tract. Nevertheless, most patients with gastroduodenal involvement have previously been diagnosed with ileocolic disease, and gastroduodenal involvement manifests later. Nonradiating epigastric pain is very common. Obstructive symptoms due to gastroduodenal strictures (eg, postprandial vomiting, epigastric pain, weight loss, bloating) are also common. 2
Duodenal ulcer. The most important factors responsible for duodenal ulcers are NSAID use and Helicobacter pylori infection.3 Duodenal ulcers have a variety of clinical presentations, ranging from no symptoms to severe pain. Epigastric pain can be sharp, dull, burning, or penetrating. Many patients complain of a feeling of hunger and weight gain—as opposed to gastric ulcer, in which patients experience anorexia and weight loss. Abdominal pain generally occurs several hours after meals and often awakens the patient at night. Pain is often relieved by food, but this phenomenon is present in only 20% to 60% of patients and probably is not specific for duodenal ulcer.
Our patient does not use NSAIDs, but some of her symptoms, such as postprandial pain, epigastric pain radiating to the back, and nausea and vomiting are seen with duodenal ulcer.
Eating disorders. The two main types of eating disorders—anorexia nervosa and bulimia nervosa—have a significant diagnostic overlap,4 and a third type, binge-eating disorder, is currently being investigated and defined. Girls and women are 10 times as likely as boys and men to develop an eating disorder.
People with anorexia have a distorted view of their bodies. Even when they are extremely thin, they see themselves as too fat.
Bulimia is characterized by binge-eating, purging, and overexercising to compensate for the excess calories. Patients are often close to normal weight.
Binge-eating disorder involves the consumption of very large amounts of food in a short period of time. About 2% of all young adults in the United States struggle with bingeeating. They are either overweight or obese.
These disorders tend to be associated with other psychiatric disorders such as depression or obsessive-compulsive disorder. Our patient sought medical attention and was appropriately concerned about her weight loss, which make an eating disorder unlikely.
CASE CONTINUED: SHE UNDERGOES CT
2. Which of the following is the most likely diagnosis at this point?
- SMA syndrome
- Chronic mesenteric ischemia involving the SMA
- Megaduodenum due to a connective tissue disorder
SMA syndrome is the most likely diagnosis. Despite its name, this syndrome is not a vascular condition. It is an uncommon cause of proximal intestinal obstruction in which the duodenum is compressed between the SMA and the aorta. First described in 1861, it has also been known as cast syndrome, Wilkie syndrome, and arteriomesenteric duodenal obstruction.5
To date, more than 400 cases of this syndrome have been reported, twice as many in women as in men. Most patients are between 20 and 40 years of age at the time of diagnosis. Common presenting symptoms include postprandial abdominal pain, nausea, vomiting, and weight loss, which may further reduce the angle between the SMA and the aorta. Diarrhea is not generally associated with this syndrome, and in our patient’s case the diarrhea was thought to be unrelated to the SMA syndrome, since it subsided spontaneously.
Conditions and events that cause, contribute to, or worsen SMA syndrome include:
- Rapid weight loss (as in cancer or burns) or lean body habitus
- Prolonged bed rest
- Use of a body cast
- Malabsorption
- Spinal disease, deformity, or trauma
- Scoliosis surgery
- Rapid linear growth without compensatory weight gain
- Abnormally high and fixed position of the ligament of Treitz
- Abdominal surgery
- Cardiac cachexia
- Unusually low origin of the SMA.7
More common causes of mechanical smallbowel obstruction are adhesions, hernias, and tumors.8 Hyperactive, high-pitched peristalsis with rushes coinciding with cramps is typical. Abdominal cramps are centered around the umbilicus or in the epigastrium and are associated with vomiting; obstipation develops in patients with complete obstruction. Patients with partial obstruction may develop diarrhea. Paralytic ileus secondary to hypokalemia is an important consideration in partial obstruction. However, abdominal radiography and CT did not confirm an obstruction, and her symptoms persisted despite correction of the potassium level.
Chronic mesenteric ischemia can be caused by vasculitis, nonocclusive conditions that cause prolonged vasoconstriction (eg, cocaine ingestion), or reduced cardiac output.9 Symptoms are due to the gradual reduction in blood flow to the intestine that occurs during eating. Our patient’s toxicology report did not suggest cocaine abuse, and her history and the workup thus far do not suggest heart failure. A workup for vasculitis was negative.
Megaduodenum, SMA-like syndrome. In rare cases, dilation of the duodenum at the level of the SMA may be part of a generalized duodenal dilation caused by something other than obstruction due to mechanical compression. There are conditions, as described below, that cause an SMA-like syndrome.
A compression defect of the duodenum at the site where the SMA crossed the duodenum was found in a series of 11 cases of systemic sclerosis.10 These patients had definite dilation of the duodenum, but it was a result of atrophy of the muscle layers and replacement by collagenous tissue, changes that result in diminished peristalsis, loss of muscle tone, and dilation. The duodenum yields to pressure in its third portion under the SMA.
Several pathologic conditions, particularly connective tissue disorders, may predispose to the development of a megaduodenum that may result in an imprint on the duodenum at the level of the SMA. The most noteworthy of these conditions is scleroderma. Other conditions that can cause reduced duodenal peristalsis include diabetes, pancreatitis, dermatomyositis, lupus erythematosus, myxedema, and amyloidosis.11
It is important to distinguish SMA syndrome from SMA-like syndromes for several reasons.12 SMA-like syndromes result in loss of normal peristalsis. Further, the conditions have different outcomes, even though they are managed similarly initially, ie, with rehydration and parenteral nutrition. Surgery is to be avoided if possible in conditions that affect widespread areas of the intestine, such as scleroderma or diabetic neuropathy.
3. Which of the following is helpful in confirming SMA syndrome?
- CT of the abdomen
- Upper GI radiography series
- Upper GI endoscopy
All three can help confirm the diagnosis.
CT of the abdomen is a convenient, safe, rapid, readily available, and relatively noninvasive way to evaluate the aortomesenteric angle and to view retroperitoneal and mesenteric fat.13 Rehydration before injecting intravenous dye is important to avoid precipitating renal failure. In this patient, CT findings that helped make the diagnosis included a narrow aortomesenteric angle, compression of the duodenum, and a paucity of fat around the SMA.
An upper GI series can reveal dilation of the first and second portions of the duodenum and abrupt compression of the duodenal mucosal folds. Other findings can include a delay of 4 to 6 hours in gastroduodenal transit and relief of the obstruction when the patient is in the left lateral decubitus position. The Hayes maneuver refers to the disappearance of these radiologic features in the knee-chest position on cinefluoroscopy.14 The findings mentioned above are best noted in the supine position on both radiography and CT.
Endoscopy is necessary to rule out mechanical causes of duodenal obstruction. A pulsatile extrinsic compression suggests this condition but is found only occasionally.
Other imaging studies, such as ultrasonography, arteriography, and hypotonic duodenography, are used less often.
4. At this time, which of the following would be the most appropriate initial treatment in this patient?
- Conservative treatment
- Narcotics
- Duodenojejunostomy
Conservative treatment is indicated initially in all cases of SMA syndrome.15 This involves reversing precipitating factors and replacing fluid, electrolytes, and nutrition via total parenteral nutrition and nasogastric decompression.
To avoid keeping the patient on intravenous therapy for a prolonged time, it is important to start enteral feeding once the pain has subsided and the patient can tolerate it. A double-lumen nasojejunal tube is passed distal to the obstruction under fluoroscopic guidance. During feedings, the patient should be in the modified knee-chest, prone, or leftside-down position, all of which increase the aortomesenteric angle.
Delaying the treatment of SMA syndrome can increase the risk of morbidity and mortality by progressive malnutrition, dehydration, oliguria, electrolyte abnormalities (eg, hypokalemia), or intestinal perforation from prolonged ischemia.16,17
Narcotics and other drugs known to slow gut motility should be avoided.
Symptoms typically improve after restoration of normal body weight. If conservative treatment fails, or if the case is severe or chronic, surgery is required.18 Fortunately, this is not required often.
Duodenojejunostomy is the most common surgical treatment and involves creation of an alternate route between the duodenum and the jejunum, bypassing the compression between the aorta and the SMA. Other procedures include gastrojejunostomy, laparoscopic duodenojejunostomy, 19 a Roux-en-Y procedure, robotically assisted duodenojejunostomy, and anterior transposition of the third portion of the duodenum. Cleavage of the ligament of Treitz is another option, enabling the duodenum to drop away from the apex of the sharpened aortomesenteric angle.
WHEN TO CONSIDER SMA SYNDROME
The SMA syndrome is an uncommon cause of a very common presenting symptom, ie, abdominal pain. Nevertheless, it should be considered in the differential diagnosis of abdominal pain, especially in patients who have conditions that cause significant weight loss, such as anorexia nervosa, malabsorption, or hypercatabolic states such as burns, major surgery, severe injuries, or malignancies. The diagnosis is based on a thorough history and on supportive findings from CT and endoscopy.
In our patient, weight loss began with nonspecific diarrhea but perpetuated itself as SMA syndrome occurred.
Appropriate management consists of interrupting the cycle of weight loss and secondary upper gut obstruction. For patients in whom more definitive therapy is not feasible, a gastrostomy tube for decompression with a jejunal extension available for feeding appears to be a reasonable and safe treatment option. Duodenojejunostomy is considered the procedure of choice in severe cases.
CASE CONCLUDED
Fortunately, our patient responded well to conservative management. She was treated with intravenous hydration and correction of electrolytes and 10 days later was able to tolerate a soft diet. She was discharged in stable condition. At a follow-up visit 2 weeks later, she reported minimal abdominal discomfort, was able to tolerate meals, and had gained a few pounds. She continues to do well.
- Iovino P, Ciacci C, Sabbatini F, Acioli DM, D'Argenio G, Mazzacca G. Esophageal impairment in adult celiac disease with steatorrhea. Am J Gastroenterol 1998; 93:1243–1249.
- Loftus EV. Upper gastrointestinal tract Crohn’s disease. Clin Perspect Gastroenterol 2002; 5:188–191.
- Zapata-Colindres JC, Zepeda-Gómez S, Montaño-Loza A, Vázquez-Ballesteros E, de Jesús Villalobos J, Valdovinos-Andraca F. The association of Helicobacter pylori infection and nonsteroidal antiinflammatory drugs in peptic ulcer disease. Can J Gastroenterol 2006; 20:277–280.
- Milos G, Spindler A, Schnyder U, Fairburn CG. Instability of eating disorder diagnoses: prospective study. Br J Psychiatry 2005; 187:573–578.
- Wilkie DP. Chronic duodenal ileus. Br J Surg 1921; 9:204–214.
- Ozkurt H, Cenker MM, Bas N, Erturk SM, Basak M. Measurement of the distance and angle between the aorta and superior mesenteric artery: normal values in different BMI categories. Surg Radiol Anat 2007; 29:595–599.
- Lippl F, Hannig C, Weiss W, Allescher HD, Classen M, Kurjak M. Superior mesenteric artery syndrome: diagnosis and treatment from the gastroenterologist's view. J Gastroenterol 2002; 37:640–643.
- Balthazar EJ. George W. Holmes Lecture. CT of small-bowel obstruction. AJR Am J Roentgenol 1994; 162:255–261.
- Chang JB, Stein TA. Mesenteric ischemia: acute and chronic. Ann Vasc Surg 2003; 17:323–328.
- Gondos B. Duodenal compression defect and the “superior mesenteric artery syndrome” 1. Radiology 1977; 123:575–580.
- Cohen LB, Field SP, Sachar DB. The superior mesenteric artery syndrome. The disease that isn't, or is it? J Clin Gastroenterol 1985; 7:113–716.
- Ahmed AR, Taylor I. Superior mesenteric artery syndrome. Postgrad Med J 1997; 73:776–778.
- Santer R, Young C, Rossi T, Riddlesberger MM. Computed tomography in superior mesenteric artery syndrome. Pediatr Radiol 1991; 21:154–155.
- Lukes PJ, Rolny P, Nilson AE, Gamklou R, Darle N, Dotevall G. Diagnostic value of hypotonic duodenography in superior mesenteric artery syndrome. Acta Chir Scand 1978; 144:39–43.
- Dietz UA, Debus ES, Heuko-Valiati L, et al. Aorto-mesenteric artery compression syndrome. Chirurg 2000; 71:1345–1351.
- Lim JE, Duke GL, Eachempati SR. Superior mesenteric artery syndrome presenting with acute massive gastric dilatation, gastric wall pneumatosis, and portal venous gas. Surgery 2003; 134:840–843.
- Fuhrman MA, Felig DM, Tanchel ME. Superior mesenteric artery syndrome with obstructing duodenal bezoar. Gastrointest Endosc 2003; 57:387.
- Hines JR, Gore RM, Ballantyne GH. Superior mesenteric artery syndrome. Diagnostic criteria and therapeutic approaches. Am J Surg 1984; 148:630–632.
- Gersin KS, Heniford BT. Laparoscopic duodenojejunostomy for treatment of superior mesenteric artery syndrome. JSLS 1998; 2:281–284.
A 20-year-old woman presents to the emergency department with postprandial epigastric and right-upper-quadrant pain, sometimes associated with nausea. She has been having six to eight loose bowel movements every day, with no blood or mucus, and she has lost about 20 lb despite a good appetite. The diarrhea did not improve when she tried omitting milk products and carbohydrates.
Her symptoms began several months ago, but she says that 3 days ago the pain worsened steadily, radiating to the middle of her back, with associated episodes of nonbloody, nonbilious emesis. She cannot keep down liquids or solids. She says she has never had such episodes in the past.
She reports no oral ulcers, urinary symptoms, skin rashes, musculoskeletal pain, or neurologic symptoms, and she denies being anxious or depressed.
She has no history of serious illness, surgery, or hospitalization. She smokes a half pack of cigarettes a day, drinks alcohol occasionally, and smokes marijuana occasionally. She is employed as a certified nursing assistant.
She is taking ethinyl estradiol-levonorgestrel pills for birth control and takes calcium carbonate as needed for abdominal discomfort. She is taking no other medications, including nonsteroidal anti-inflammatory drugs (NSAIDs).
Her maternal uncle died of colon cancer at age 32, and her mother had colon polyps on colonoscopy. There is no family history of inflammatory bowel disease or celiac sprue. Her father committed suicide.
Her laboratory values
- White blood cell count 10.2 × 109/L (normal range 4–11)
- Red blood cell count 4.71 × 1012/L (3.9–5.5)
- Hemoglobin 14.4 g/dL (12–16)
- Hematocrit 42.4% (37%–47%)
- Mean corpuscular volume 90 fL (83–99)
- Mean corpuscular hemoglobin 30.6 pg (27–33)
- Platelet count 230 × 109/L (150–400)
- Red cell distribution width 13.3% (11.5%–14.5%)
- Sodium 140 mmol/L (132–148)
- Potassium 3.3 mmol/L (3.5–5.0)
- Chloride 104 mmol/L (98–111)
- Bicarbonate 28 mmol/L (23–32)
- Blood urea nitrogen 9 mg/dL (8–25)
- Creatinine 0.8 mg/dL (0.7–1.4)
- Glucose 87 mg/dL (65–100)
- Alanine aminotransferase 26 U/L (0–45)
- Aspartate aminotransferase 21 U/L (7–40)
- Alkaline phosphatase 101 U/L (40–150)
- Total bilirubin 0.8 mg/dL (0–1.5)
- Albumin 3.5 g/dL (3.5–5)
- Pregnancy screen negative
- Urine toxicology screen negative.
Physical examination
The patient is very thin and appears quite uncomfortable. Her temperature is 99.7°F (37.6°C), pulse rate 101, respiratory rate 18, blood pressure 111/67 mm Hg, and oxygen saturation 96% on room air. Her skin is warm and dry. Her height is 66 inches, weight 116 lb, and body mass index 18.7.
Examination of the head and neck shows normal dentition, dry mucus membranes, and no oral exudates. The thyroid is normal, and no masses or lymphadenopathy are noted.
Heart sounds and rhythm are normal, and the lungs are clear with no crackles or rubs. The abdomen is scaphoid and soft, with no distention. She has epigastric tenderness but no rebound, guarding, rigidity, palpable mass, or costovertebral angle tenderness. Bowel sounds are normal. The neurologic examination is normal.
NARROWING THE DIAGNOSIS
1. Given the history and findings so far, which is the least likely cause of her symptoms?
- Lactose intolerance
- Celiac disease
- Crohn disease
- Duodenal ulcer
- Eating disorder
This young woman’s presentation has some features found in all of these conditions. However, the least likely is lactose intolerance.
Lactose intolerance results from a shortage of the enzyme lactase, which is normally produced by the cells that line the small intestine. Close to 50 million American adults have lactose intolerance. Common symptoms include nausea, cramps, bloating, gas, and diarrhea, which begin about 30 minutes to 2 hours after eating or drinking foods containing lactose.
Since the patient’s symptoms did not improve when she tried omitting milk products, and since lactose intolerance is rarely associated with pain radiating to the back and with severe vomiting, this is the least likely cause of her symptoms.
Celiac disease presents with a myriad of symptoms—sometimes without gastrointestinal (GI) symptoms. Anemia is the most common laboratory finding, due most often to iron deficiency, but also due to deficiencies of vitamin B12 and folate as a result of malabsorption.1
Our patient’s laboratory values—especially her red cell indices—do not confirm this finding. One must also remember, however, that hemoglobin tends to be falsely elevated in patients who are dehydrated.
Crohn disease often presents with occult blood loss, low-grade fever, weight loss, and anemia. Though the condition is most often ileocolic, it can affect any part of the gastrointestinal tract. Nevertheless, most patients with gastroduodenal involvement have previously been diagnosed with ileocolic disease, and gastroduodenal involvement manifests later. Nonradiating epigastric pain is very common. Obstructive symptoms due to gastroduodenal strictures (eg, postprandial vomiting, epigastric pain, weight loss, bloating) are also common. 2
Duodenal ulcer. The most important factors responsible for duodenal ulcers are NSAID use and Helicobacter pylori infection.3 Duodenal ulcers have a variety of clinical presentations, ranging from no symptoms to severe pain. Epigastric pain can be sharp, dull, burning, or penetrating. Many patients complain of a feeling of hunger and weight gain—as opposed to gastric ulcer, in which patients experience anorexia and weight loss. Abdominal pain generally occurs several hours after meals and often awakens the patient at night. Pain is often relieved by food, but this phenomenon is present in only 20% to 60% of patients and probably is not specific for duodenal ulcer.
Our patient does not use NSAIDs, but some of her symptoms, such as postprandial pain, epigastric pain radiating to the back, and nausea and vomiting are seen with duodenal ulcer.
Eating disorders. The two main types of eating disorders—anorexia nervosa and bulimia nervosa—have a significant diagnostic overlap,4 and a third type, binge-eating disorder, is currently being investigated and defined. Girls and women are 10 times as likely as boys and men to develop an eating disorder.
People with anorexia have a distorted view of their bodies. Even when they are extremely thin, they see themselves as too fat.
Bulimia is characterized by binge-eating, purging, and overexercising to compensate for the excess calories. Patients are often close to normal weight.
Binge-eating disorder involves the consumption of very large amounts of food in a short period of time. About 2% of all young adults in the United States struggle with bingeeating. They are either overweight or obese.
These disorders tend to be associated with other psychiatric disorders such as depression or obsessive-compulsive disorder. Our patient sought medical attention and was appropriately concerned about her weight loss, which make an eating disorder unlikely.
CASE CONTINUED: SHE UNDERGOES CT
2. Which of the following is the most likely diagnosis at this point?
- SMA syndrome
- Chronic mesenteric ischemia involving the SMA
- Megaduodenum due to a connective tissue disorder
SMA syndrome is the most likely diagnosis. Despite its name, this syndrome is not a vascular condition. It is an uncommon cause of proximal intestinal obstruction in which the duodenum is compressed between the SMA and the aorta. First described in 1861, it has also been known as cast syndrome, Wilkie syndrome, and arteriomesenteric duodenal obstruction.5
To date, more than 400 cases of this syndrome have been reported, twice as many in women as in men. Most patients are between 20 and 40 years of age at the time of diagnosis. Common presenting symptoms include postprandial abdominal pain, nausea, vomiting, and weight loss, which may further reduce the angle between the SMA and the aorta. Diarrhea is not generally associated with this syndrome, and in our patient’s case the diarrhea was thought to be unrelated to the SMA syndrome, since it subsided spontaneously.
Conditions and events that cause, contribute to, or worsen SMA syndrome include:
- Rapid weight loss (as in cancer or burns) or lean body habitus
- Prolonged bed rest
- Use of a body cast
- Malabsorption
- Spinal disease, deformity, or trauma
- Scoliosis surgery
- Rapid linear growth without compensatory weight gain
- Abnormally high and fixed position of the ligament of Treitz
- Abdominal surgery
- Cardiac cachexia
- Unusually low origin of the SMA.7
More common causes of mechanical smallbowel obstruction are adhesions, hernias, and tumors.8 Hyperactive, high-pitched peristalsis with rushes coinciding with cramps is typical. Abdominal cramps are centered around the umbilicus or in the epigastrium and are associated with vomiting; obstipation develops in patients with complete obstruction. Patients with partial obstruction may develop diarrhea. Paralytic ileus secondary to hypokalemia is an important consideration in partial obstruction. However, abdominal radiography and CT did not confirm an obstruction, and her symptoms persisted despite correction of the potassium level.
Chronic mesenteric ischemia can be caused by vasculitis, nonocclusive conditions that cause prolonged vasoconstriction (eg, cocaine ingestion), or reduced cardiac output.9 Symptoms are due to the gradual reduction in blood flow to the intestine that occurs during eating. Our patient’s toxicology report did not suggest cocaine abuse, and her history and the workup thus far do not suggest heart failure. A workup for vasculitis was negative.
Megaduodenum, SMA-like syndrome. In rare cases, dilation of the duodenum at the level of the SMA may be part of a generalized duodenal dilation caused by something other than obstruction due to mechanical compression. There are conditions, as described below, that cause an SMA-like syndrome.
A compression defect of the duodenum at the site where the SMA crossed the duodenum was found in a series of 11 cases of systemic sclerosis.10 These patients had definite dilation of the duodenum, but it was a result of atrophy of the muscle layers and replacement by collagenous tissue, changes that result in diminished peristalsis, loss of muscle tone, and dilation. The duodenum yields to pressure in its third portion under the SMA.
Several pathologic conditions, particularly connective tissue disorders, may predispose to the development of a megaduodenum that may result in an imprint on the duodenum at the level of the SMA. The most noteworthy of these conditions is scleroderma. Other conditions that can cause reduced duodenal peristalsis include diabetes, pancreatitis, dermatomyositis, lupus erythematosus, myxedema, and amyloidosis.11
It is important to distinguish SMA syndrome from SMA-like syndromes for several reasons.12 SMA-like syndromes result in loss of normal peristalsis. Further, the conditions have different outcomes, even though they are managed similarly initially, ie, with rehydration and parenteral nutrition. Surgery is to be avoided if possible in conditions that affect widespread areas of the intestine, such as scleroderma or diabetic neuropathy.
3. Which of the following is helpful in confirming SMA syndrome?
- CT of the abdomen
- Upper GI radiography series
- Upper GI endoscopy
All three can help confirm the diagnosis.
CT of the abdomen is a convenient, safe, rapid, readily available, and relatively noninvasive way to evaluate the aortomesenteric angle and to view retroperitoneal and mesenteric fat.13 Rehydration before injecting intravenous dye is important to avoid precipitating renal failure. In this patient, CT findings that helped make the diagnosis included a narrow aortomesenteric angle, compression of the duodenum, and a paucity of fat around the SMA.
An upper GI series can reveal dilation of the first and second portions of the duodenum and abrupt compression of the duodenal mucosal folds. Other findings can include a delay of 4 to 6 hours in gastroduodenal transit and relief of the obstruction when the patient is in the left lateral decubitus position. The Hayes maneuver refers to the disappearance of these radiologic features in the knee-chest position on cinefluoroscopy.14 The findings mentioned above are best noted in the supine position on both radiography and CT.
Endoscopy is necessary to rule out mechanical causes of duodenal obstruction. A pulsatile extrinsic compression suggests this condition but is found only occasionally.
Other imaging studies, such as ultrasonography, arteriography, and hypotonic duodenography, are used less often.
4. At this time, which of the following would be the most appropriate initial treatment in this patient?
- Conservative treatment
- Narcotics
- Duodenojejunostomy
Conservative treatment is indicated initially in all cases of SMA syndrome.15 This involves reversing precipitating factors and replacing fluid, electrolytes, and nutrition via total parenteral nutrition and nasogastric decompression.
To avoid keeping the patient on intravenous therapy for a prolonged time, it is important to start enteral feeding once the pain has subsided and the patient can tolerate it. A double-lumen nasojejunal tube is passed distal to the obstruction under fluoroscopic guidance. During feedings, the patient should be in the modified knee-chest, prone, or leftside-down position, all of which increase the aortomesenteric angle.
Delaying the treatment of SMA syndrome can increase the risk of morbidity and mortality by progressive malnutrition, dehydration, oliguria, electrolyte abnormalities (eg, hypokalemia), or intestinal perforation from prolonged ischemia.16,17
Narcotics and other drugs known to slow gut motility should be avoided.
Symptoms typically improve after restoration of normal body weight. If conservative treatment fails, or if the case is severe or chronic, surgery is required.18 Fortunately, this is not required often.
Duodenojejunostomy is the most common surgical treatment and involves creation of an alternate route between the duodenum and the jejunum, bypassing the compression between the aorta and the SMA. Other procedures include gastrojejunostomy, laparoscopic duodenojejunostomy, 19 a Roux-en-Y procedure, robotically assisted duodenojejunostomy, and anterior transposition of the third portion of the duodenum. Cleavage of the ligament of Treitz is another option, enabling the duodenum to drop away from the apex of the sharpened aortomesenteric angle.
WHEN TO CONSIDER SMA SYNDROME
The SMA syndrome is an uncommon cause of a very common presenting symptom, ie, abdominal pain. Nevertheless, it should be considered in the differential diagnosis of abdominal pain, especially in patients who have conditions that cause significant weight loss, such as anorexia nervosa, malabsorption, or hypercatabolic states such as burns, major surgery, severe injuries, or malignancies. The diagnosis is based on a thorough history and on supportive findings from CT and endoscopy.
In our patient, weight loss began with nonspecific diarrhea but perpetuated itself as SMA syndrome occurred.
Appropriate management consists of interrupting the cycle of weight loss and secondary upper gut obstruction. For patients in whom more definitive therapy is not feasible, a gastrostomy tube for decompression with a jejunal extension available for feeding appears to be a reasonable and safe treatment option. Duodenojejunostomy is considered the procedure of choice in severe cases.
CASE CONCLUDED
Fortunately, our patient responded well to conservative management. She was treated with intravenous hydration and correction of electrolytes and 10 days later was able to tolerate a soft diet. She was discharged in stable condition. At a follow-up visit 2 weeks later, she reported minimal abdominal discomfort, was able to tolerate meals, and had gained a few pounds. She continues to do well.
A 20-year-old woman presents to the emergency department with postprandial epigastric and right-upper-quadrant pain, sometimes associated with nausea. She has been having six to eight loose bowel movements every day, with no blood or mucus, and she has lost about 20 lb despite a good appetite. The diarrhea did not improve when she tried omitting milk products and carbohydrates.
Her symptoms began several months ago, but she says that 3 days ago the pain worsened steadily, radiating to the middle of her back, with associated episodes of nonbloody, nonbilious emesis. She cannot keep down liquids or solids. She says she has never had such episodes in the past.
She reports no oral ulcers, urinary symptoms, skin rashes, musculoskeletal pain, or neurologic symptoms, and she denies being anxious or depressed.
She has no history of serious illness, surgery, or hospitalization. She smokes a half pack of cigarettes a day, drinks alcohol occasionally, and smokes marijuana occasionally. She is employed as a certified nursing assistant.
She is taking ethinyl estradiol-levonorgestrel pills for birth control and takes calcium carbonate as needed for abdominal discomfort. She is taking no other medications, including nonsteroidal anti-inflammatory drugs (NSAIDs).
Her maternal uncle died of colon cancer at age 32, and her mother had colon polyps on colonoscopy. There is no family history of inflammatory bowel disease or celiac sprue. Her father committed suicide.
Her laboratory values
- White blood cell count 10.2 × 109/L (normal range 4–11)
- Red blood cell count 4.71 × 1012/L (3.9–5.5)
- Hemoglobin 14.4 g/dL (12–16)
- Hematocrit 42.4% (37%–47%)
- Mean corpuscular volume 90 fL (83–99)
- Mean corpuscular hemoglobin 30.6 pg (27–33)
- Platelet count 230 × 109/L (150–400)
- Red cell distribution width 13.3% (11.5%–14.5%)
- Sodium 140 mmol/L (132–148)
- Potassium 3.3 mmol/L (3.5–5.0)
- Chloride 104 mmol/L (98–111)
- Bicarbonate 28 mmol/L (23–32)
- Blood urea nitrogen 9 mg/dL (8–25)
- Creatinine 0.8 mg/dL (0.7–1.4)
- Glucose 87 mg/dL (65–100)
- Alanine aminotransferase 26 U/L (0–45)
- Aspartate aminotransferase 21 U/L (7–40)
- Alkaline phosphatase 101 U/L (40–150)
- Total bilirubin 0.8 mg/dL (0–1.5)
- Albumin 3.5 g/dL (3.5–5)
- Pregnancy screen negative
- Urine toxicology screen negative.
Physical examination
The patient is very thin and appears quite uncomfortable. Her temperature is 99.7°F (37.6°C), pulse rate 101, respiratory rate 18, blood pressure 111/67 mm Hg, and oxygen saturation 96% on room air. Her skin is warm and dry. Her height is 66 inches, weight 116 lb, and body mass index 18.7.
Examination of the head and neck shows normal dentition, dry mucus membranes, and no oral exudates. The thyroid is normal, and no masses or lymphadenopathy are noted.
Heart sounds and rhythm are normal, and the lungs are clear with no crackles or rubs. The abdomen is scaphoid and soft, with no distention. She has epigastric tenderness but no rebound, guarding, rigidity, palpable mass, or costovertebral angle tenderness. Bowel sounds are normal. The neurologic examination is normal.
NARROWING THE DIAGNOSIS
1. Given the history and findings so far, which is the least likely cause of her symptoms?
- Lactose intolerance
- Celiac disease
- Crohn disease
- Duodenal ulcer
- Eating disorder
This young woman’s presentation has some features found in all of these conditions. However, the least likely is lactose intolerance.
Lactose intolerance results from a shortage of the enzyme lactase, which is normally produced by the cells that line the small intestine. Close to 50 million American adults have lactose intolerance. Common symptoms include nausea, cramps, bloating, gas, and diarrhea, which begin about 30 minutes to 2 hours after eating or drinking foods containing lactose.
Since the patient’s symptoms did not improve when she tried omitting milk products, and since lactose intolerance is rarely associated with pain radiating to the back and with severe vomiting, this is the least likely cause of her symptoms.
Celiac disease presents with a myriad of symptoms—sometimes without gastrointestinal (GI) symptoms. Anemia is the most common laboratory finding, due most often to iron deficiency, but also due to deficiencies of vitamin B12 and folate as a result of malabsorption.1
Our patient’s laboratory values—especially her red cell indices—do not confirm this finding. One must also remember, however, that hemoglobin tends to be falsely elevated in patients who are dehydrated.
Crohn disease often presents with occult blood loss, low-grade fever, weight loss, and anemia. Though the condition is most often ileocolic, it can affect any part of the gastrointestinal tract. Nevertheless, most patients with gastroduodenal involvement have previously been diagnosed with ileocolic disease, and gastroduodenal involvement manifests later. Nonradiating epigastric pain is very common. Obstructive symptoms due to gastroduodenal strictures (eg, postprandial vomiting, epigastric pain, weight loss, bloating) are also common. 2
Duodenal ulcer. The most important factors responsible for duodenal ulcers are NSAID use and Helicobacter pylori infection.3 Duodenal ulcers have a variety of clinical presentations, ranging from no symptoms to severe pain. Epigastric pain can be sharp, dull, burning, or penetrating. Many patients complain of a feeling of hunger and weight gain—as opposed to gastric ulcer, in which patients experience anorexia and weight loss. Abdominal pain generally occurs several hours after meals and often awakens the patient at night. Pain is often relieved by food, but this phenomenon is present in only 20% to 60% of patients and probably is not specific for duodenal ulcer.
Our patient does not use NSAIDs, but some of her symptoms, such as postprandial pain, epigastric pain radiating to the back, and nausea and vomiting are seen with duodenal ulcer.
Eating disorders. The two main types of eating disorders—anorexia nervosa and bulimia nervosa—have a significant diagnostic overlap,4 and a third type, binge-eating disorder, is currently being investigated and defined. Girls and women are 10 times as likely as boys and men to develop an eating disorder.
People with anorexia have a distorted view of their bodies. Even when they are extremely thin, they see themselves as too fat.
Bulimia is characterized by binge-eating, purging, and overexercising to compensate for the excess calories. Patients are often close to normal weight.
Binge-eating disorder involves the consumption of very large amounts of food in a short period of time. About 2% of all young adults in the United States struggle with bingeeating. They are either overweight or obese.
These disorders tend to be associated with other psychiatric disorders such as depression or obsessive-compulsive disorder. Our patient sought medical attention and was appropriately concerned about her weight loss, which make an eating disorder unlikely.
CASE CONTINUED: SHE UNDERGOES CT
2. Which of the following is the most likely diagnosis at this point?
- SMA syndrome
- Chronic mesenteric ischemia involving the SMA
- Megaduodenum due to a connective tissue disorder
SMA syndrome is the most likely diagnosis. Despite its name, this syndrome is not a vascular condition. It is an uncommon cause of proximal intestinal obstruction in which the duodenum is compressed between the SMA and the aorta. First described in 1861, it has also been known as cast syndrome, Wilkie syndrome, and arteriomesenteric duodenal obstruction.5
To date, more than 400 cases of this syndrome have been reported, twice as many in women as in men. Most patients are between 20 and 40 years of age at the time of diagnosis. Common presenting symptoms include postprandial abdominal pain, nausea, vomiting, and weight loss, which may further reduce the angle between the SMA and the aorta. Diarrhea is not generally associated with this syndrome, and in our patient’s case the diarrhea was thought to be unrelated to the SMA syndrome, since it subsided spontaneously.
Conditions and events that cause, contribute to, or worsen SMA syndrome include:
- Rapid weight loss (as in cancer or burns) or lean body habitus
- Prolonged bed rest
- Use of a body cast
- Malabsorption
- Spinal disease, deformity, or trauma
- Scoliosis surgery
- Rapid linear growth without compensatory weight gain
- Abnormally high and fixed position of the ligament of Treitz
- Abdominal surgery
- Cardiac cachexia
- Unusually low origin of the SMA.7
More common causes of mechanical smallbowel obstruction are adhesions, hernias, and tumors.8 Hyperactive, high-pitched peristalsis with rushes coinciding with cramps is typical. Abdominal cramps are centered around the umbilicus or in the epigastrium and are associated with vomiting; obstipation develops in patients with complete obstruction. Patients with partial obstruction may develop diarrhea. Paralytic ileus secondary to hypokalemia is an important consideration in partial obstruction. However, abdominal radiography and CT did not confirm an obstruction, and her symptoms persisted despite correction of the potassium level.
Chronic mesenteric ischemia can be caused by vasculitis, nonocclusive conditions that cause prolonged vasoconstriction (eg, cocaine ingestion), or reduced cardiac output.9 Symptoms are due to the gradual reduction in blood flow to the intestine that occurs during eating. Our patient’s toxicology report did not suggest cocaine abuse, and her history and the workup thus far do not suggest heart failure. A workup for vasculitis was negative.
Megaduodenum, SMA-like syndrome. In rare cases, dilation of the duodenum at the level of the SMA may be part of a generalized duodenal dilation caused by something other than obstruction due to mechanical compression. There are conditions, as described below, that cause an SMA-like syndrome.
A compression defect of the duodenum at the site where the SMA crossed the duodenum was found in a series of 11 cases of systemic sclerosis.10 These patients had definite dilation of the duodenum, but it was a result of atrophy of the muscle layers and replacement by collagenous tissue, changes that result in diminished peristalsis, loss of muscle tone, and dilation. The duodenum yields to pressure in its third portion under the SMA.
Several pathologic conditions, particularly connective tissue disorders, may predispose to the development of a megaduodenum that may result in an imprint on the duodenum at the level of the SMA. The most noteworthy of these conditions is scleroderma. Other conditions that can cause reduced duodenal peristalsis include diabetes, pancreatitis, dermatomyositis, lupus erythematosus, myxedema, and amyloidosis.11
It is important to distinguish SMA syndrome from SMA-like syndromes for several reasons.12 SMA-like syndromes result in loss of normal peristalsis. Further, the conditions have different outcomes, even though they are managed similarly initially, ie, with rehydration and parenteral nutrition. Surgery is to be avoided if possible in conditions that affect widespread areas of the intestine, such as scleroderma or diabetic neuropathy.
3. Which of the following is helpful in confirming SMA syndrome?
- CT of the abdomen
- Upper GI radiography series
- Upper GI endoscopy
All three can help confirm the diagnosis.
CT of the abdomen is a convenient, safe, rapid, readily available, and relatively noninvasive way to evaluate the aortomesenteric angle and to view retroperitoneal and mesenteric fat.13 Rehydration before injecting intravenous dye is important to avoid precipitating renal failure. In this patient, CT findings that helped make the diagnosis included a narrow aortomesenteric angle, compression of the duodenum, and a paucity of fat around the SMA.
An upper GI series can reveal dilation of the first and second portions of the duodenum and abrupt compression of the duodenal mucosal folds. Other findings can include a delay of 4 to 6 hours in gastroduodenal transit and relief of the obstruction when the patient is in the left lateral decubitus position. The Hayes maneuver refers to the disappearance of these radiologic features in the knee-chest position on cinefluoroscopy.14 The findings mentioned above are best noted in the supine position on both radiography and CT.
Endoscopy is necessary to rule out mechanical causes of duodenal obstruction. A pulsatile extrinsic compression suggests this condition but is found only occasionally.
Other imaging studies, such as ultrasonography, arteriography, and hypotonic duodenography, are used less often.
4. At this time, which of the following would be the most appropriate initial treatment in this patient?
- Conservative treatment
- Narcotics
- Duodenojejunostomy
Conservative treatment is indicated initially in all cases of SMA syndrome.15 This involves reversing precipitating factors and replacing fluid, electrolytes, and nutrition via total parenteral nutrition and nasogastric decompression.
To avoid keeping the patient on intravenous therapy for a prolonged time, it is important to start enteral feeding once the pain has subsided and the patient can tolerate it. A double-lumen nasojejunal tube is passed distal to the obstruction under fluoroscopic guidance. During feedings, the patient should be in the modified knee-chest, prone, or leftside-down position, all of which increase the aortomesenteric angle.
Delaying the treatment of SMA syndrome can increase the risk of morbidity and mortality by progressive malnutrition, dehydration, oliguria, electrolyte abnormalities (eg, hypokalemia), or intestinal perforation from prolonged ischemia.16,17
Narcotics and other drugs known to slow gut motility should be avoided.
Symptoms typically improve after restoration of normal body weight. If conservative treatment fails, or if the case is severe or chronic, surgery is required.18 Fortunately, this is not required often.
Duodenojejunostomy is the most common surgical treatment and involves creation of an alternate route between the duodenum and the jejunum, bypassing the compression between the aorta and the SMA. Other procedures include gastrojejunostomy, laparoscopic duodenojejunostomy, 19 a Roux-en-Y procedure, robotically assisted duodenojejunostomy, and anterior transposition of the third portion of the duodenum. Cleavage of the ligament of Treitz is another option, enabling the duodenum to drop away from the apex of the sharpened aortomesenteric angle.
WHEN TO CONSIDER SMA SYNDROME
The SMA syndrome is an uncommon cause of a very common presenting symptom, ie, abdominal pain. Nevertheless, it should be considered in the differential diagnosis of abdominal pain, especially in patients who have conditions that cause significant weight loss, such as anorexia nervosa, malabsorption, or hypercatabolic states such as burns, major surgery, severe injuries, or malignancies. The diagnosis is based on a thorough history and on supportive findings from CT and endoscopy.
In our patient, weight loss began with nonspecific diarrhea but perpetuated itself as SMA syndrome occurred.
Appropriate management consists of interrupting the cycle of weight loss and secondary upper gut obstruction. For patients in whom more definitive therapy is not feasible, a gastrostomy tube for decompression with a jejunal extension available for feeding appears to be a reasonable and safe treatment option. Duodenojejunostomy is considered the procedure of choice in severe cases.
CASE CONCLUDED
Fortunately, our patient responded well to conservative management. She was treated with intravenous hydration and correction of electrolytes and 10 days later was able to tolerate a soft diet. She was discharged in stable condition. At a follow-up visit 2 weeks later, she reported minimal abdominal discomfort, was able to tolerate meals, and had gained a few pounds. She continues to do well.
- Iovino P, Ciacci C, Sabbatini F, Acioli DM, D'Argenio G, Mazzacca G. Esophageal impairment in adult celiac disease with steatorrhea. Am J Gastroenterol 1998; 93:1243–1249.
- Loftus EV. Upper gastrointestinal tract Crohn’s disease. Clin Perspect Gastroenterol 2002; 5:188–191.
- Zapata-Colindres JC, Zepeda-Gómez S, Montaño-Loza A, Vázquez-Ballesteros E, de Jesús Villalobos J, Valdovinos-Andraca F. The association of Helicobacter pylori infection and nonsteroidal antiinflammatory drugs in peptic ulcer disease. Can J Gastroenterol 2006; 20:277–280.
- Milos G, Spindler A, Schnyder U, Fairburn CG. Instability of eating disorder diagnoses: prospective study. Br J Psychiatry 2005; 187:573–578.
- Wilkie DP. Chronic duodenal ileus. Br J Surg 1921; 9:204–214.
- Ozkurt H, Cenker MM, Bas N, Erturk SM, Basak M. Measurement of the distance and angle between the aorta and superior mesenteric artery: normal values in different BMI categories. Surg Radiol Anat 2007; 29:595–599.
- Lippl F, Hannig C, Weiss W, Allescher HD, Classen M, Kurjak M. Superior mesenteric artery syndrome: diagnosis and treatment from the gastroenterologist's view. J Gastroenterol 2002; 37:640–643.
- Balthazar EJ. George W. Holmes Lecture. CT of small-bowel obstruction. AJR Am J Roentgenol 1994; 162:255–261.
- Chang JB, Stein TA. Mesenteric ischemia: acute and chronic. Ann Vasc Surg 2003; 17:323–328.
- Gondos B. Duodenal compression defect and the “superior mesenteric artery syndrome” 1. Radiology 1977; 123:575–580.
- Cohen LB, Field SP, Sachar DB. The superior mesenteric artery syndrome. The disease that isn't, or is it? J Clin Gastroenterol 1985; 7:113–716.
- Ahmed AR, Taylor I. Superior mesenteric artery syndrome. Postgrad Med J 1997; 73:776–778.
- Santer R, Young C, Rossi T, Riddlesberger MM. Computed tomography in superior mesenteric artery syndrome. Pediatr Radiol 1991; 21:154–155.
- Lukes PJ, Rolny P, Nilson AE, Gamklou R, Darle N, Dotevall G. Diagnostic value of hypotonic duodenography in superior mesenteric artery syndrome. Acta Chir Scand 1978; 144:39–43.
- Dietz UA, Debus ES, Heuko-Valiati L, et al. Aorto-mesenteric artery compression syndrome. Chirurg 2000; 71:1345–1351.
- Lim JE, Duke GL, Eachempati SR. Superior mesenteric artery syndrome presenting with acute massive gastric dilatation, gastric wall pneumatosis, and portal venous gas. Surgery 2003; 134:840–843.
- Fuhrman MA, Felig DM, Tanchel ME. Superior mesenteric artery syndrome with obstructing duodenal bezoar. Gastrointest Endosc 2003; 57:387.
- Hines JR, Gore RM, Ballantyne GH. Superior mesenteric artery syndrome. Diagnostic criteria and therapeutic approaches. Am J Surg 1984; 148:630–632.
- Gersin KS, Heniford BT. Laparoscopic duodenojejunostomy for treatment of superior mesenteric artery syndrome. JSLS 1998; 2:281–284.
- Iovino P, Ciacci C, Sabbatini F, Acioli DM, D'Argenio G, Mazzacca G. Esophageal impairment in adult celiac disease with steatorrhea. Am J Gastroenterol 1998; 93:1243–1249.
- Loftus EV. Upper gastrointestinal tract Crohn’s disease. Clin Perspect Gastroenterol 2002; 5:188–191.
- Zapata-Colindres JC, Zepeda-Gómez S, Montaño-Loza A, Vázquez-Ballesteros E, de Jesús Villalobos J, Valdovinos-Andraca F. The association of Helicobacter pylori infection and nonsteroidal antiinflammatory drugs in peptic ulcer disease. Can J Gastroenterol 2006; 20:277–280.
- Milos G, Spindler A, Schnyder U, Fairburn CG. Instability of eating disorder diagnoses: prospective study. Br J Psychiatry 2005; 187:573–578.
- Wilkie DP. Chronic duodenal ileus. Br J Surg 1921; 9:204–214.
- Ozkurt H, Cenker MM, Bas N, Erturk SM, Basak M. Measurement of the distance and angle between the aorta and superior mesenteric artery: normal values in different BMI categories. Surg Radiol Anat 2007; 29:595–599.
- Lippl F, Hannig C, Weiss W, Allescher HD, Classen M, Kurjak M. Superior mesenteric artery syndrome: diagnosis and treatment from the gastroenterologist's view. J Gastroenterol 2002; 37:640–643.
- Balthazar EJ. George W. Holmes Lecture. CT of small-bowel obstruction. AJR Am J Roentgenol 1994; 162:255–261.
- Chang JB, Stein TA. Mesenteric ischemia: acute and chronic. Ann Vasc Surg 2003; 17:323–328.
- Gondos B. Duodenal compression defect and the “superior mesenteric artery syndrome” 1. Radiology 1977; 123:575–580.
- Cohen LB, Field SP, Sachar DB. The superior mesenteric artery syndrome. The disease that isn't, or is it? J Clin Gastroenterol 1985; 7:113–716.
- Ahmed AR, Taylor I. Superior mesenteric artery syndrome. Postgrad Med J 1997; 73:776–778.
- Santer R, Young C, Rossi T, Riddlesberger MM. Computed tomography in superior mesenteric artery syndrome. Pediatr Radiol 1991; 21:154–155.
- Lukes PJ, Rolny P, Nilson AE, Gamklou R, Darle N, Dotevall G. Diagnostic value of hypotonic duodenography in superior mesenteric artery syndrome. Acta Chir Scand 1978; 144:39–43.
- Dietz UA, Debus ES, Heuko-Valiati L, et al. Aorto-mesenteric artery compression syndrome. Chirurg 2000; 71:1345–1351.
- Lim JE, Duke GL, Eachempati SR. Superior mesenteric artery syndrome presenting with acute massive gastric dilatation, gastric wall pneumatosis, and portal venous gas. Surgery 2003; 134:840–843.
- Fuhrman MA, Felig DM, Tanchel ME. Superior mesenteric artery syndrome with obstructing duodenal bezoar. Gastrointest Endosc 2003; 57:387.
- Hines JR, Gore RM, Ballantyne GH. Superior mesenteric artery syndrome. Diagnostic criteria and therapeutic approaches. Am J Surg 1984; 148:630–632.
- Gersin KS, Heniford BT. Laparoscopic duodenojejunostomy for treatment of superior mesenteric artery syndrome. JSLS 1998; 2:281–284.
Heel Pain and Difficulty Bearing Weight
Fibula Stress Fracture Mimicking a Malignancy
Childhood Obesity Boosts LV Size, Cardiovascular Risk
ORLANDO — A growing number of American children have increased left ventricular mass, a marker for cardiovascular disease risk.
The finding was noted in a study that included 700 children and “is the first study to look at average left ventricular mass in the whole pediatric population,” according to Dr. David I. Crowley, a pediatric cardiologist at Cincinnati Children's Hospital.
In children with an average age of 10 years, mean left ventricular (LV) mass rose by a statistically significant 4% from 1986 to 2008. The prevalence of LV hypertrophy in the children more than doubled, from 7% to 15%, Dr. Crowley said at the annual scientific sessions of the American Heart Association.
The increase appears to be linked to obesity. In the 1986-1988 cohort of 350 children examined at Cincinnati Children's, the prevalence of overweight was 14% and of obesity was 5%. In a matched cohort of 350 children assessed in 2008, the prevalence of overweight was 15% but the prevalence of obesity soared to 19%. Results from a multivariate analysis showed that body mass index was a major determinant of LV mass, Dr. Crowley said.
The study included children aged 2-19 years. The participants came to Cincinnati Children's in 1986-1988 for an echocardiography examination because of a murmur, palpitations, syncope, or chest pain. All 350 children included in the analysis had normal cardiac anatomy and function, and none had systemic disease or a body mass index of 40 kg/m
Analysis of the echocardiographic data showed that, in addition to having larger hearts, the more recently evaluated children also had a greater prevalence of high-risk cardiac morphology. The prevalence of eccentric hypertrophy was 6% in the 1986-1988 group and 12% in the 2008 cohort. The prevalence of concentric hypertrophy also doubled in the more recent cohort.
Although average LV mass rose by only 4% from the older to more contemporary cohort, this difference is important, said Dr. Stephen R. Daniels. “When you look at a population and a value gets worse by even a small amount, it suggests that many more in the population may now be in a high-risk category,” said Dr. Daniels, a pediatric cardiologist at the University of Colorado in Denver.
Dr. Crowley had no financial conflicts.
In the 2008 cohort, 'the prevalence of obesity soared to 19%' vs. 5% in the 1986-1988 cohort.
Source DR. CROWLEY
ORLANDO — A growing number of American children have increased left ventricular mass, a marker for cardiovascular disease risk.
The finding was noted in a study that included 700 children and “is the first study to look at average left ventricular mass in the whole pediatric population,” according to Dr. David I. Crowley, a pediatric cardiologist at Cincinnati Children's Hospital.
In children with an average age of 10 years, mean left ventricular (LV) mass rose by a statistically significant 4% from 1986 to 2008. The prevalence of LV hypertrophy in the children more than doubled, from 7% to 15%, Dr. Crowley said at the annual scientific sessions of the American Heart Association.
The increase appears to be linked to obesity. In the 1986-1988 cohort of 350 children examined at Cincinnati Children's, the prevalence of overweight was 14% and of obesity was 5%. In a matched cohort of 350 children assessed in 2008, the prevalence of overweight was 15% but the prevalence of obesity soared to 19%. Results from a multivariate analysis showed that body mass index was a major determinant of LV mass, Dr. Crowley said.
The study included children aged 2-19 years. The participants came to Cincinnati Children's in 1986-1988 for an echocardiography examination because of a murmur, palpitations, syncope, or chest pain. All 350 children included in the analysis had normal cardiac anatomy and function, and none had systemic disease or a body mass index of 40 kg/m
Analysis of the echocardiographic data showed that, in addition to having larger hearts, the more recently evaluated children also had a greater prevalence of high-risk cardiac morphology. The prevalence of eccentric hypertrophy was 6% in the 1986-1988 group and 12% in the 2008 cohort. The prevalence of concentric hypertrophy also doubled in the more recent cohort.
Although average LV mass rose by only 4% from the older to more contemporary cohort, this difference is important, said Dr. Stephen R. Daniels. “When you look at a population and a value gets worse by even a small amount, it suggests that many more in the population may now be in a high-risk category,” said Dr. Daniels, a pediatric cardiologist at the University of Colorado in Denver.
Dr. Crowley had no financial conflicts.
In the 2008 cohort, 'the prevalence of obesity soared to 19%' vs. 5% in the 1986-1988 cohort.
Source DR. CROWLEY
ORLANDO — A growing number of American children have increased left ventricular mass, a marker for cardiovascular disease risk.
The finding was noted in a study that included 700 children and “is the first study to look at average left ventricular mass in the whole pediatric population,” according to Dr. David I. Crowley, a pediatric cardiologist at Cincinnati Children's Hospital.
In children with an average age of 10 years, mean left ventricular (LV) mass rose by a statistically significant 4% from 1986 to 2008. The prevalence of LV hypertrophy in the children more than doubled, from 7% to 15%, Dr. Crowley said at the annual scientific sessions of the American Heart Association.
The increase appears to be linked to obesity. In the 1986-1988 cohort of 350 children examined at Cincinnati Children's, the prevalence of overweight was 14% and of obesity was 5%. In a matched cohort of 350 children assessed in 2008, the prevalence of overweight was 15% but the prevalence of obesity soared to 19%. Results from a multivariate analysis showed that body mass index was a major determinant of LV mass, Dr. Crowley said.
The study included children aged 2-19 years. The participants came to Cincinnati Children's in 1986-1988 for an echocardiography examination because of a murmur, palpitations, syncope, or chest pain. All 350 children included in the analysis had normal cardiac anatomy and function, and none had systemic disease or a body mass index of 40 kg/m
Analysis of the echocardiographic data showed that, in addition to having larger hearts, the more recently evaluated children also had a greater prevalence of high-risk cardiac morphology. The prevalence of eccentric hypertrophy was 6% in the 1986-1988 group and 12% in the 2008 cohort. The prevalence of concentric hypertrophy also doubled in the more recent cohort.
Although average LV mass rose by only 4% from the older to more contemporary cohort, this difference is important, said Dr. Stephen R. Daniels. “When you look at a population and a value gets worse by even a small amount, it suggests that many more in the population may now be in a high-risk category,” said Dr. Daniels, a pediatric cardiologist at the University of Colorado in Denver.
Dr. Crowley had no financial conflicts.
In the 2008 cohort, 'the prevalence of obesity soared to 19%' vs. 5% in the 1986-1988 cohort.
Source DR. CROWLEY
Patients With Acute MI Get High Radiation Doses
ORLANDO — Patients hospitalized for acute MI receive an average cumulative ionizing radiation dose from imaging studies that's equivalent to 725 chest x-rays, a study indicated.
The study of 64,074 consecutive MI patients admitted at 49 academic hospitals during 2006-2009 showed that they received an average of four imaging studies involving ionizing radiation exposure totaling 14.52 mSv per admission, Dr. Prashant Kaul reported at the annual scientific sessions of the American Heart Association.
That's nearly 5 times the average person's annual background radiation exposure, and close to 30% of the annual maximum permitted for radiation workers, noted Dr. Kaul, a cardiovascular medicine fellow at Duke University, Durham, N.C.
He and his coinvestigators are now trying to figure out how much of this radiation exposure might have been avoidable.
The study points to a new way to consider radiation safety in the medical environment, Dr. Kaul noted.
“Up until this point we've been thinking about radiation as it relates to an individual imaging test,” Dr. Kaul said. “How much radiation do I get with a CT scan? How much do I get with a cardiac catheterization? We're thinking about these doses in isolation. But we believe that it may be more appropriate to think about radiation doses per episode of care for a given diagnosis,” he said.
'It may be more appropriate to think about radiation doses per episode of care for a given diagnosis.'
Source DR. KAUL
MI patients receive nearly 5 times the average radiation exposure.
Source ©Elena Selivanova/iStockphoto.com
ORLANDO — Patients hospitalized for acute MI receive an average cumulative ionizing radiation dose from imaging studies that's equivalent to 725 chest x-rays, a study indicated.
The study of 64,074 consecutive MI patients admitted at 49 academic hospitals during 2006-2009 showed that they received an average of four imaging studies involving ionizing radiation exposure totaling 14.52 mSv per admission, Dr. Prashant Kaul reported at the annual scientific sessions of the American Heart Association.
That's nearly 5 times the average person's annual background radiation exposure, and close to 30% of the annual maximum permitted for radiation workers, noted Dr. Kaul, a cardiovascular medicine fellow at Duke University, Durham, N.C.
He and his coinvestigators are now trying to figure out how much of this radiation exposure might have been avoidable.
The study points to a new way to consider radiation safety in the medical environment, Dr. Kaul noted.
“Up until this point we've been thinking about radiation as it relates to an individual imaging test,” Dr. Kaul said. “How much radiation do I get with a CT scan? How much do I get with a cardiac catheterization? We're thinking about these doses in isolation. But we believe that it may be more appropriate to think about radiation doses per episode of care for a given diagnosis,” he said.
'It may be more appropriate to think about radiation doses per episode of care for a given diagnosis.'
Source DR. KAUL
MI patients receive nearly 5 times the average radiation exposure.
Source ©Elena Selivanova/iStockphoto.com
ORLANDO — Patients hospitalized for acute MI receive an average cumulative ionizing radiation dose from imaging studies that's equivalent to 725 chest x-rays, a study indicated.
The study of 64,074 consecutive MI patients admitted at 49 academic hospitals during 2006-2009 showed that they received an average of four imaging studies involving ionizing radiation exposure totaling 14.52 mSv per admission, Dr. Prashant Kaul reported at the annual scientific sessions of the American Heart Association.
That's nearly 5 times the average person's annual background radiation exposure, and close to 30% of the annual maximum permitted for radiation workers, noted Dr. Kaul, a cardiovascular medicine fellow at Duke University, Durham, N.C.
He and his coinvestigators are now trying to figure out how much of this radiation exposure might have been avoidable.
The study points to a new way to consider radiation safety in the medical environment, Dr. Kaul noted.
“Up until this point we've been thinking about radiation as it relates to an individual imaging test,” Dr. Kaul said. “How much radiation do I get with a CT scan? How much do I get with a cardiac catheterization? We're thinking about these doses in isolation. But we believe that it may be more appropriate to think about radiation doses per episode of care for a given diagnosis,” he said.
'It may be more appropriate to think about radiation doses per episode of care for a given diagnosis.'
Source DR. KAUL
MI patients receive nearly 5 times the average radiation exposure.
Source ©Elena Selivanova/iStockphoto.com
Survival Benefit of CT Angiography Shown
ORLANDO — Patients who had their coronary calcium levels imaged by CT angiography had substantially better survival than did similar patients who underwent standard management, an observational study has shown.
The findings, which involved more than 4,000 patients followed for more than 6 years, could have implications for insurance reimbursement of CT angiography, Dr. Matthew J. Budoff said at the annual scientific sessions of the American Heart Association. He hypothesized that the mortality difference between patients who underwent CT imaging and those who did not may be explained by improved compliance with therapy among patients who were able to see the extent of their calcified coronary disease.
Although several payers including United Healthcare, Aetna, Medicare, and Medicaid currently reimburse for CT angiography, the national policy of Blue Cross/Blue Shield is not to cover these examinations. The Blues' stated policy is that they will not cover new diagnostic tests until their value in improving patient outcomes is proved, Dr. Budoff said. He believes the new data mean this standard has now been met, but he acknowledged that the study was observational and not a prospective, randomized trial. Nonetheless, the size and duration of the study, as well as the striking magnitude of beneficial effect, should be persuasive, said Dr. Budoff, program director of cardiology at the Los Angeles Biomedical Research Institute at Harbor–UCLA Medical Center.
In his study, 2,538 symptomatic patients referred for assessment of possible coronary disease and evaluated by coronary CT had a 52% reduced risk of all-cause death during an average 6.7-year follow-up compared with a similar group of 1,706 patients whose work-up did not include CT angiography.
“Increased awareness of coronary artery disease severity among people undergoing CT angiography may have contributed to their survival,” Dr. Budoff said.
“Probable mechanisms include increased adherence to and use of anti-atherosclerotic therapies, such as statins, angiotensin-converting enzyme inhibitors, and anti-platelet drugs” such as aspirin, he added.
Dr. Budoff shows patients in his clinic who undergo coronary CT and have coronary calcium six images of their coronary arteries that depict the calcium deposits and stenoses.
“I think that this is something that leads to compliance. It's very black and white. Patients can see their plaque and stenosis and know they need treatment,” he said in an interview. Patients also receive their calcium scores.
The total of 4,244 symptomatic patients in the study had an average age of 58, and 62% did not have known coronary artery disease. The patients who underwent coronary CT and those who received standard care without coronary CT imaging were treated in the academic cardiology clinic at Harbor-UCLA. The two groups were matched by age, gender, the time when they were first seen, and their conventional cardiac risk factors.
All patients undergoing coronary CT had the examination covered by their insurance providers; none of the patients paid for the exam out of pocket. One factor that the study did not control for was socioeconomic status. The patients who did not undergo CT angiography may have been, as a group, somewhat poorer than those who had CT examinations, Dr. Budoff said.
During an average 80-month follow-up the all-cause mortality rate was 3% in patients who had CT examinations and 11% in those who did not, a statistically significant difference. Mortality rates began to diverge between the two groups after about 3 years, and then continued to diverge.
In a multivariate analysis that controlled for age, gender, and coronary risk factors, patients who had standard care had a fourfold higher risk of dying than did those who had CT angiography.
Dr. Budoff has served on the speakers bureau for GE, a company that markets CT equipment. None of his associates in the study had any financial disclosures.
'It's very black and white. Patients can see their plaque and stenosis and know they need treatment.'
Source DR. BUDOFF
ORLANDO — Patients who had their coronary calcium levels imaged by CT angiography had substantially better survival than did similar patients who underwent standard management, an observational study has shown.
The findings, which involved more than 4,000 patients followed for more than 6 years, could have implications for insurance reimbursement of CT angiography, Dr. Matthew J. Budoff said at the annual scientific sessions of the American Heart Association. He hypothesized that the mortality difference between patients who underwent CT imaging and those who did not may be explained by improved compliance with therapy among patients who were able to see the extent of their calcified coronary disease.
Although several payers including United Healthcare, Aetna, Medicare, and Medicaid currently reimburse for CT angiography, the national policy of Blue Cross/Blue Shield is not to cover these examinations. The Blues' stated policy is that they will not cover new diagnostic tests until their value in improving patient outcomes is proved, Dr. Budoff said. He believes the new data mean this standard has now been met, but he acknowledged that the study was observational and not a prospective, randomized trial. Nonetheless, the size and duration of the study, as well as the striking magnitude of beneficial effect, should be persuasive, said Dr. Budoff, program director of cardiology at the Los Angeles Biomedical Research Institute at Harbor–UCLA Medical Center.
In his study, 2,538 symptomatic patients referred for assessment of possible coronary disease and evaluated by coronary CT had a 52% reduced risk of all-cause death during an average 6.7-year follow-up compared with a similar group of 1,706 patients whose work-up did not include CT angiography.
“Increased awareness of coronary artery disease severity among people undergoing CT angiography may have contributed to their survival,” Dr. Budoff said.
“Probable mechanisms include increased adherence to and use of anti-atherosclerotic therapies, such as statins, angiotensin-converting enzyme inhibitors, and anti-platelet drugs” such as aspirin, he added.
Dr. Budoff shows patients in his clinic who undergo coronary CT and have coronary calcium six images of their coronary arteries that depict the calcium deposits and stenoses.
“I think that this is something that leads to compliance. It's very black and white. Patients can see their plaque and stenosis and know they need treatment,” he said in an interview. Patients also receive their calcium scores.
The total of 4,244 symptomatic patients in the study had an average age of 58, and 62% did not have known coronary artery disease. The patients who underwent coronary CT and those who received standard care without coronary CT imaging were treated in the academic cardiology clinic at Harbor-UCLA. The two groups were matched by age, gender, the time when they were first seen, and their conventional cardiac risk factors.
All patients undergoing coronary CT had the examination covered by their insurance providers; none of the patients paid for the exam out of pocket. One factor that the study did not control for was socioeconomic status. The patients who did not undergo CT angiography may have been, as a group, somewhat poorer than those who had CT examinations, Dr. Budoff said.
During an average 80-month follow-up the all-cause mortality rate was 3% in patients who had CT examinations and 11% in those who did not, a statistically significant difference. Mortality rates began to diverge between the two groups after about 3 years, and then continued to diverge.
In a multivariate analysis that controlled for age, gender, and coronary risk factors, patients who had standard care had a fourfold higher risk of dying than did those who had CT angiography.
Dr. Budoff has served on the speakers bureau for GE, a company that markets CT equipment. None of his associates in the study had any financial disclosures.
'It's very black and white. Patients can see their plaque and stenosis and know they need treatment.'
Source DR. BUDOFF
ORLANDO — Patients who had their coronary calcium levels imaged by CT angiography had substantially better survival than did similar patients who underwent standard management, an observational study has shown.
The findings, which involved more than 4,000 patients followed for more than 6 years, could have implications for insurance reimbursement of CT angiography, Dr. Matthew J. Budoff said at the annual scientific sessions of the American Heart Association. He hypothesized that the mortality difference between patients who underwent CT imaging and those who did not may be explained by improved compliance with therapy among patients who were able to see the extent of their calcified coronary disease.
Although several payers including United Healthcare, Aetna, Medicare, and Medicaid currently reimburse for CT angiography, the national policy of Blue Cross/Blue Shield is not to cover these examinations. The Blues' stated policy is that they will not cover new diagnostic tests until their value in improving patient outcomes is proved, Dr. Budoff said. He believes the new data mean this standard has now been met, but he acknowledged that the study was observational and not a prospective, randomized trial. Nonetheless, the size and duration of the study, as well as the striking magnitude of beneficial effect, should be persuasive, said Dr. Budoff, program director of cardiology at the Los Angeles Biomedical Research Institute at Harbor–UCLA Medical Center.
In his study, 2,538 symptomatic patients referred for assessment of possible coronary disease and evaluated by coronary CT had a 52% reduced risk of all-cause death during an average 6.7-year follow-up compared with a similar group of 1,706 patients whose work-up did not include CT angiography.
“Increased awareness of coronary artery disease severity among people undergoing CT angiography may have contributed to their survival,” Dr. Budoff said.
“Probable mechanisms include increased adherence to and use of anti-atherosclerotic therapies, such as statins, angiotensin-converting enzyme inhibitors, and anti-platelet drugs” such as aspirin, he added.
Dr. Budoff shows patients in his clinic who undergo coronary CT and have coronary calcium six images of their coronary arteries that depict the calcium deposits and stenoses.
“I think that this is something that leads to compliance. It's very black and white. Patients can see their plaque and stenosis and know they need treatment,” he said in an interview. Patients also receive their calcium scores.
The total of 4,244 symptomatic patients in the study had an average age of 58, and 62% did not have known coronary artery disease. The patients who underwent coronary CT and those who received standard care without coronary CT imaging were treated in the academic cardiology clinic at Harbor-UCLA. The two groups were matched by age, gender, the time when they were first seen, and their conventional cardiac risk factors.
All patients undergoing coronary CT had the examination covered by their insurance providers; none of the patients paid for the exam out of pocket. One factor that the study did not control for was socioeconomic status. The patients who did not undergo CT angiography may have been, as a group, somewhat poorer than those who had CT examinations, Dr. Budoff said.
During an average 80-month follow-up the all-cause mortality rate was 3% in patients who had CT examinations and 11% in those who did not, a statistically significant difference. Mortality rates began to diverge between the two groups after about 3 years, and then continued to diverge.
In a multivariate analysis that controlled for age, gender, and coronary risk factors, patients who had standard care had a fourfold higher risk of dying than did those who had CT angiography.
Dr. Budoff has served on the speakers bureau for GE, a company that markets CT equipment. None of his associates in the study had any financial disclosures.
'It's very black and white. Patients can see their plaque and stenosis and know they need treatment.'
Source DR. BUDOFF
NSF Uncommon After Contrast Agent Black Box Warnings
GAITHERSBURG, MD. — Black box warnings that have been added to the labels of all gadolinium-based MRI contrast agents have reduced the number of reported nephrogenic systemic fibrosis events to almost none during the past year, according to an analysis by Dr. James Kaiser.
“The numbers of new events have tapered dramatically, probably due to public awareness of the association of NSF [nephrogenic systemic fibrosis] with GBCA [gadolinium-based contrast agent] administration,” he said at a joint meeting of the Food and Drug Administration's Cardiovascular and Renal Drugs and Drug Safety and Risk Management advisory committees.
Event dates are based on either the date of administration of contrast or the date of diagnosis of NSF.
The FDA began receiving reports of NSF possibly being linked to gadolinium-based contrast agents in 2006, when 194 event dates were reported.
This reporting “probably reflects awareness of the medical community of the potential connection between GBCA administration and NSF and changes in radiologic practice,” said Dr. Kaiser of the FDA's office of surveillance and epidemiology. There were 128 reported events in 2007, 55 in 2008, and 6 in 2009 (through September).
In 2007, the FDA asked manufacturers to include a boxed warning on the product labels of all gadolinium-based contrast agents. The warnings caution that patients with severe kidney insufficiency who receive gadolinium-based agents are at increased risk for the development of NSF.
In addition, patients who are in need of a liver transplantation, those who have just undergone liver transplantation, patients who have chronic liver disease, and patients experiencing kidney insufficiency of any severity also have an increased risk of NSF.
Five gadolinium-based contrast agents have been approved for use in the United States: Magnevist (gadopentetate dimeglumine); Omniscan (gadodiamide); OptiMARK (gadoversetamide); MultiHance (gadobenate dimeglumine); and ProHance (gadoteridol).
As of September 2009, a total of 382 reports of NSF had been associated with Omniscan (GE HealthCare), 195 with Magnevist (Bayer HealthCare), 35 with OptiMARK (Covidien), 1 with MultiHance (Bracco Diagnostics), and 0 with ProHance (Bracco Diagnostics). These numbers are based on reported cases in which a patient had known exposure to only one gadolinium-based contrast agent.
Although there was no formal vote during the committee meeting, the FDA asked the committees to consider whether warning labels should continue to be grouped together as a class or if there was adequate evidence to single out contrast agents that increase the risk of NSF.
“The majority of the group feels that at least two of the agents appear to be different from the other agents,” said Dr. Robert A. Harrington, who chairs the Cardiovascular and Renal Drugs Advisory Committee. The majority of the committee members recommended that the use of Omniscan and OptiMARK be contraindicated in patients who have severe kidney dysfunction. However, there was uncertainty as to how to define severe kidney dysfunction.
There was less consensus on whether a third agent, Magnevist, might also warrant contraindication language. As for the other agents, “there was no clear evidence that any one single agent was safe in this patient population,” Dr. Harrington noted.
GAITHERSBURG, MD. — Black box warnings that have been added to the labels of all gadolinium-based MRI contrast agents have reduced the number of reported nephrogenic systemic fibrosis events to almost none during the past year, according to an analysis by Dr. James Kaiser.
“The numbers of new events have tapered dramatically, probably due to public awareness of the association of NSF [nephrogenic systemic fibrosis] with GBCA [gadolinium-based contrast agent] administration,” he said at a joint meeting of the Food and Drug Administration's Cardiovascular and Renal Drugs and Drug Safety and Risk Management advisory committees.
Event dates are based on either the date of administration of contrast or the date of diagnosis of NSF.
The FDA began receiving reports of NSF possibly being linked to gadolinium-based contrast agents in 2006, when 194 event dates were reported.
This reporting “probably reflects awareness of the medical community of the potential connection between GBCA administration and NSF and changes in radiologic practice,” said Dr. Kaiser of the FDA's office of surveillance and epidemiology. There were 128 reported events in 2007, 55 in 2008, and 6 in 2009 (through September).
In 2007, the FDA asked manufacturers to include a boxed warning on the product labels of all gadolinium-based contrast agents. The warnings caution that patients with severe kidney insufficiency who receive gadolinium-based agents are at increased risk for the development of NSF.
In addition, patients who are in need of a liver transplantation, those who have just undergone liver transplantation, patients who have chronic liver disease, and patients experiencing kidney insufficiency of any severity also have an increased risk of NSF.
Five gadolinium-based contrast agents have been approved for use in the United States: Magnevist (gadopentetate dimeglumine); Omniscan (gadodiamide); OptiMARK (gadoversetamide); MultiHance (gadobenate dimeglumine); and ProHance (gadoteridol).
As of September 2009, a total of 382 reports of NSF had been associated with Omniscan (GE HealthCare), 195 with Magnevist (Bayer HealthCare), 35 with OptiMARK (Covidien), 1 with MultiHance (Bracco Diagnostics), and 0 with ProHance (Bracco Diagnostics). These numbers are based on reported cases in which a patient had known exposure to only one gadolinium-based contrast agent.
Although there was no formal vote during the committee meeting, the FDA asked the committees to consider whether warning labels should continue to be grouped together as a class or if there was adequate evidence to single out contrast agents that increase the risk of NSF.
“The majority of the group feels that at least two of the agents appear to be different from the other agents,” said Dr. Robert A. Harrington, who chairs the Cardiovascular and Renal Drugs Advisory Committee. The majority of the committee members recommended that the use of Omniscan and OptiMARK be contraindicated in patients who have severe kidney dysfunction. However, there was uncertainty as to how to define severe kidney dysfunction.
There was less consensus on whether a third agent, Magnevist, might also warrant contraindication language. As for the other agents, “there was no clear evidence that any one single agent was safe in this patient population,” Dr. Harrington noted.
GAITHERSBURG, MD. — Black box warnings that have been added to the labels of all gadolinium-based MRI contrast agents have reduced the number of reported nephrogenic systemic fibrosis events to almost none during the past year, according to an analysis by Dr. James Kaiser.
“The numbers of new events have tapered dramatically, probably due to public awareness of the association of NSF [nephrogenic systemic fibrosis] with GBCA [gadolinium-based contrast agent] administration,” he said at a joint meeting of the Food and Drug Administration's Cardiovascular and Renal Drugs and Drug Safety and Risk Management advisory committees.
Event dates are based on either the date of administration of contrast or the date of diagnosis of NSF.
The FDA began receiving reports of NSF possibly being linked to gadolinium-based contrast agents in 2006, when 194 event dates were reported.
This reporting “probably reflects awareness of the medical community of the potential connection between GBCA administration and NSF and changes in radiologic practice,” said Dr. Kaiser of the FDA's office of surveillance and epidemiology. There were 128 reported events in 2007, 55 in 2008, and 6 in 2009 (through September).
In 2007, the FDA asked manufacturers to include a boxed warning on the product labels of all gadolinium-based contrast agents. The warnings caution that patients with severe kidney insufficiency who receive gadolinium-based agents are at increased risk for the development of NSF.
In addition, patients who are in need of a liver transplantation, those who have just undergone liver transplantation, patients who have chronic liver disease, and patients experiencing kidney insufficiency of any severity also have an increased risk of NSF.
Five gadolinium-based contrast agents have been approved for use in the United States: Magnevist (gadopentetate dimeglumine); Omniscan (gadodiamide); OptiMARK (gadoversetamide); MultiHance (gadobenate dimeglumine); and ProHance (gadoteridol).
As of September 2009, a total of 382 reports of NSF had been associated with Omniscan (GE HealthCare), 195 with Magnevist (Bayer HealthCare), 35 with OptiMARK (Covidien), 1 with MultiHance (Bracco Diagnostics), and 0 with ProHance (Bracco Diagnostics). These numbers are based on reported cases in which a patient had known exposure to only one gadolinium-based contrast agent.
Although there was no formal vote during the committee meeting, the FDA asked the committees to consider whether warning labels should continue to be grouped together as a class or if there was adequate evidence to single out contrast agents that increase the risk of NSF.
“The majority of the group feels that at least two of the agents appear to be different from the other agents,” said Dr. Robert A. Harrington, who chairs the Cardiovascular and Renal Drugs Advisory Committee. The majority of the committee members recommended that the use of Omniscan and OptiMARK be contraindicated in patients who have severe kidney dysfunction. However, there was uncertainty as to how to define severe kidney dysfunction.
There was less consensus on whether a third agent, Magnevist, might also warrant contraindication language. As for the other agents, “there was no clear evidence that any one single agent was safe in this patient population,” Dr. Harrington noted.
Contrast Agent Restrictions May Help Curb NSF
Findings: No new cases of nephrogenic systemic fibrosis were reported after reduction in use of gadolinium-based contrast agents, as well as substitution of new agents.
Data Source: Patient records at two tertiary care centers.
Disclosure: One study author received research support from GE Healthcare, Bayer Healthcare Pharmaceuticals, and Bracco, makers of gadolinium-based contrast agents used in the study.
No new cases of nephrogenic systemic fibrosis occurred at two large tertiary care facilities after more restrictive policies on the use of gadolinium-based contrast agents were introduced.
Before the changes, the incidence of nephrogenic systemic fibrosis (NSF) was 1 in 33 in high-risk patients. In patients on dialysis, the incidence of NSF was 1 in 35, according Dr. Ersan Altun, a radiologist at the University of North Carolina in Chapel Hill, and his coauthors.
“The absence of NSF cases in the postadoption period may reflect the effect of the use of different GBCAs [gadolinium-based contrast agents] and the adoption of restrictive GBCA policies on the incidence of NSF,” they wrote (Radiology 2009;253:689–96).
In 2006, reports to the Food and Drug Administration suggested a strong association between NSF and gadolinium-based contrast agents used in MRI. The exact mechanism remains unknown; however, GBCAs vary in their dissociation rates, and dissociation of the gadolinium ion from the chelating ligand may be a risk factor for NSF, the researchers said.
Cases of NSF were documented at two tertiary care centers for three periods: before the adoption of restrictive GBCA policies and a change in agents, during the transition period, and after the adoption of these policieschanges.
The new policies included careful screening of patients for risk factors for NSF such as renal disease, hypertension, dialysis, and diabetes before they underwent gadolinium-enhanced MRI. If GBCA-enhanced imaging was unavoidable in a patient deemed to be at high risk, a half dose of gadobenate dimeglumine was used. The policies also specified greater use of other types of imaging that don't require contrast agents.
In addition, gadolinium-enhanced MRI was not performed in pregnant women unless maternal survival was at stake, was not performed in any patient twice within 48 hours unless absolutely necessary, and was not done twice within 48 hours in any patient deemed to be at high risk of NSF.
Before the adoption of the changes, both of the centers used gadodiamide (Omniscan, GE Healthcare). After the adoption of revised policies, both centers used either gadobenate dimeglumine (Multihance, Bracco Diagnostics) or gadopentetate dimeglumine (Magnevist, Bayer Healthcare Pharmaceuticals). Gadobenate was used for all MRI studies of adults, patients younger than 1 year, and pediatric patients at risk for the development of NSF. Gadopentetate was used for pediatric patients 1 year and older who were not at risk for NSF. Both of the agents have lower dissociation rates than gadodiamide.
Patients considered to be at high risk for NSF were defined as having stage 4 or 5 chronic renal disease, undergoing dialysis, having acute renal insufficiency (including patients with hepatorenal syndrome), and being in the perioperative liver transplantation period. Patients considered to be at low risk were those who had stage 3 chronic renal disease, children less than 1 year of age, and pregnant patients. NSF was diagnosed by clinical findings and histopathologic evaluation of deep-skin biopsy.
At center A, 35 patients with NSF were identified in the preadoption period; of these, 28 underwent MRI with gadodiamide. The benchmark incidence of NSF at center A was 1/1,750 and the NSF incidence in high-risk patients was 1/33.
At center B, 14 patients with NSF were identified in the preadoption period; of these, 9 underwent MRI with gadodiamide. The benchmark incidence of NSF at center B was 1/1,803 and the NSF incidence in dialysis patients was 1/35.
There were no cases of NSF in the transitional and postadoption periods at either center.
My Take
Prevention of NSF Remains a Challenge
It's important to note that the reported decrease in NSF may not have occurred simply because new contrast agents were used. The more restrictive policies on the use of contrast agents might account for the improvement.
Companies that manufacture alternative contrast agents have a clear financial incentive in conducting and reporting such research. This study is by no means definitive, nor should the findings be construed to mean that a flat-out switch to an alternative agent is recommended.
That being said, we've only begun to scratch the surface of NSF. We don't understand the pathophysiology of the disorder, nor do we have any factor other than known renal disease that we can use to stratify patients for NSF risk.
Clearly, we still have a long way to go in addressing the problem of NSF.
FRANK MICHOTA, M.D., is the Director of Academic Affairs in the Department of Hospital Medicine at the Cleveland Clinic. He reports no relevant conflicts of interest.
Findings: No new cases of nephrogenic systemic fibrosis were reported after reduction in use of gadolinium-based contrast agents, as well as substitution of new agents.
Data Source: Patient records at two tertiary care centers.
Disclosure: One study author received research support from GE Healthcare, Bayer Healthcare Pharmaceuticals, and Bracco, makers of gadolinium-based contrast agents used in the study.
No new cases of nephrogenic systemic fibrosis occurred at two large tertiary care facilities after more restrictive policies on the use of gadolinium-based contrast agents were introduced.
Before the changes, the incidence of nephrogenic systemic fibrosis (NSF) was 1 in 33 in high-risk patients. In patients on dialysis, the incidence of NSF was 1 in 35, according Dr. Ersan Altun, a radiologist at the University of North Carolina in Chapel Hill, and his coauthors.
“The absence of NSF cases in the postadoption period may reflect the effect of the use of different GBCAs [gadolinium-based contrast agents] and the adoption of restrictive GBCA policies on the incidence of NSF,” they wrote (Radiology 2009;253:689–96).
In 2006, reports to the Food and Drug Administration suggested a strong association between NSF and gadolinium-based contrast agents used in MRI. The exact mechanism remains unknown; however, GBCAs vary in their dissociation rates, and dissociation of the gadolinium ion from the chelating ligand may be a risk factor for NSF, the researchers said.
Cases of NSF were documented at two tertiary care centers for three periods: before the adoption of restrictive GBCA policies and a change in agents, during the transition period, and after the adoption of these policieschanges.
The new policies included careful screening of patients for risk factors for NSF such as renal disease, hypertension, dialysis, and diabetes before they underwent gadolinium-enhanced MRI. If GBCA-enhanced imaging was unavoidable in a patient deemed to be at high risk, a half dose of gadobenate dimeglumine was used. The policies also specified greater use of other types of imaging that don't require contrast agents.
In addition, gadolinium-enhanced MRI was not performed in pregnant women unless maternal survival was at stake, was not performed in any patient twice within 48 hours unless absolutely necessary, and was not done twice within 48 hours in any patient deemed to be at high risk of NSF.
Before the adoption of the changes, both of the centers used gadodiamide (Omniscan, GE Healthcare). After the adoption of revised policies, both centers used either gadobenate dimeglumine (Multihance, Bracco Diagnostics) or gadopentetate dimeglumine (Magnevist, Bayer Healthcare Pharmaceuticals). Gadobenate was used for all MRI studies of adults, patients younger than 1 year, and pediatric patients at risk for the development of NSF. Gadopentetate was used for pediatric patients 1 year and older who were not at risk for NSF. Both of the agents have lower dissociation rates than gadodiamide.
Patients considered to be at high risk for NSF were defined as having stage 4 or 5 chronic renal disease, undergoing dialysis, having acute renal insufficiency (including patients with hepatorenal syndrome), and being in the perioperative liver transplantation period. Patients considered to be at low risk were those who had stage 3 chronic renal disease, children less than 1 year of age, and pregnant patients. NSF was diagnosed by clinical findings and histopathologic evaluation of deep-skin biopsy.
At center A, 35 patients with NSF were identified in the preadoption period; of these, 28 underwent MRI with gadodiamide. The benchmark incidence of NSF at center A was 1/1,750 and the NSF incidence in high-risk patients was 1/33.
At center B, 14 patients with NSF were identified in the preadoption period; of these, 9 underwent MRI with gadodiamide. The benchmark incidence of NSF at center B was 1/1,803 and the NSF incidence in dialysis patients was 1/35.
There were no cases of NSF in the transitional and postadoption periods at either center.
My Take
Prevention of NSF Remains a Challenge
It's important to note that the reported decrease in NSF may not have occurred simply because new contrast agents were used. The more restrictive policies on the use of contrast agents might account for the improvement.
Companies that manufacture alternative contrast agents have a clear financial incentive in conducting and reporting such research. This study is by no means definitive, nor should the findings be construed to mean that a flat-out switch to an alternative agent is recommended.
That being said, we've only begun to scratch the surface of NSF. We don't understand the pathophysiology of the disorder, nor do we have any factor other than known renal disease that we can use to stratify patients for NSF risk.
Clearly, we still have a long way to go in addressing the problem of NSF.
FRANK MICHOTA, M.D., is the Director of Academic Affairs in the Department of Hospital Medicine at the Cleveland Clinic. He reports no relevant conflicts of interest.
Findings: No new cases of nephrogenic systemic fibrosis were reported after reduction in use of gadolinium-based contrast agents, as well as substitution of new agents.
Data Source: Patient records at two tertiary care centers.
Disclosure: One study author received research support from GE Healthcare, Bayer Healthcare Pharmaceuticals, and Bracco, makers of gadolinium-based contrast agents used in the study.
No new cases of nephrogenic systemic fibrosis occurred at two large tertiary care facilities after more restrictive policies on the use of gadolinium-based contrast agents were introduced.
Before the changes, the incidence of nephrogenic systemic fibrosis (NSF) was 1 in 33 in high-risk patients. In patients on dialysis, the incidence of NSF was 1 in 35, according Dr. Ersan Altun, a radiologist at the University of North Carolina in Chapel Hill, and his coauthors.
“The absence of NSF cases in the postadoption period may reflect the effect of the use of different GBCAs [gadolinium-based contrast agents] and the adoption of restrictive GBCA policies on the incidence of NSF,” they wrote (Radiology 2009;253:689–96).
In 2006, reports to the Food and Drug Administration suggested a strong association between NSF and gadolinium-based contrast agents used in MRI. The exact mechanism remains unknown; however, GBCAs vary in their dissociation rates, and dissociation of the gadolinium ion from the chelating ligand may be a risk factor for NSF, the researchers said.
Cases of NSF were documented at two tertiary care centers for three periods: before the adoption of restrictive GBCA policies and a change in agents, during the transition period, and after the adoption of these policieschanges.
The new policies included careful screening of patients for risk factors for NSF such as renal disease, hypertension, dialysis, and diabetes before they underwent gadolinium-enhanced MRI. If GBCA-enhanced imaging was unavoidable in a patient deemed to be at high risk, a half dose of gadobenate dimeglumine was used. The policies also specified greater use of other types of imaging that don't require contrast agents.
In addition, gadolinium-enhanced MRI was not performed in pregnant women unless maternal survival was at stake, was not performed in any patient twice within 48 hours unless absolutely necessary, and was not done twice within 48 hours in any patient deemed to be at high risk of NSF.
Before the adoption of the changes, both of the centers used gadodiamide (Omniscan, GE Healthcare). After the adoption of revised policies, both centers used either gadobenate dimeglumine (Multihance, Bracco Diagnostics) or gadopentetate dimeglumine (Magnevist, Bayer Healthcare Pharmaceuticals). Gadobenate was used for all MRI studies of adults, patients younger than 1 year, and pediatric patients at risk for the development of NSF. Gadopentetate was used for pediatric patients 1 year and older who were not at risk for NSF. Both of the agents have lower dissociation rates than gadodiamide.
Patients considered to be at high risk for NSF were defined as having stage 4 or 5 chronic renal disease, undergoing dialysis, having acute renal insufficiency (including patients with hepatorenal syndrome), and being in the perioperative liver transplantation period. Patients considered to be at low risk were those who had stage 3 chronic renal disease, children less than 1 year of age, and pregnant patients. NSF was diagnosed by clinical findings and histopathologic evaluation of deep-skin biopsy.
At center A, 35 patients with NSF were identified in the preadoption period; of these, 28 underwent MRI with gadodiamide. The benchmark incidence of NSF at center A was 1/1,750 and the NSF incidence in high-risk patients was 1/33.
At center B, 14 patients with NSF were identified in the preadoption period; of these, 9 underwent MRI with gadodiamide. The benchmark incidence of NSF at center B was 1/1,803 and the NSF incidence in dialysis patients was 1/35.
There were no cases of NSF in the transitional and postadoption periods at either center.
My Take
Prevention of NSF Remains a Challenge
It's important to note that the reported decrease in NSF may not have occurred simply because new contrast agents were used. The more restrictive policies on the use of contrast agents might account for the improvement.
Companies that manufacture alternative contrast agents have a clear financial incentive in conducting and reporting such research. This study is by no means definitive, nor should the findings be construed to mean that a flat-out switch to an alternative agent is recommended.
That being said, we've only begun to scratch the surface of NSF. We don't understand the pathophysiology of the disorder, nor do we have any factor other than known renal disease that we can use to stratify patients for NSF risk.
Clearly, we still have a long way to go in addressing the problem of NSF.
FRANK MICHOTA, M.D., is the Director of Academic Affairs in the Department of Hospital Medicine at the Cleveland Clinic. He reports no relevant conflicts of interest.