Imaging

LAS VEGAS — Duplex-guided balloon angioplasty provides excellent visualization and spares patients exposure to radiation and potential nephrotoxicity from contrast agents, said Dr. Enrico Ascher at the spring meeting of the American College of Surgeons.

Patients with diabetes and those with preexisting renal disease are particularly well served by the duplex approach, said Dr. Ascher, director of the vascular surgery division at Maimonides Medical Center in Brooklyn, N.Y., and professor of surgery at Mt. Sinai Medical Center in New York. However, all patients benefit from the myriad advantages of duplex-guided procedures, including multiplanar imaging and five- to sixfold magnification; the ability to view the entire vessel wall rather than just the lumen; and more precise measurement for, selection of, and placement of stents.

Furthermore, duplex techniques allow two ways of immediately assessing the adequacy of the procedure: visualization of the anatomy and hemodynamic confirmation, he said.

“I'm not here to say x-ray is bad or dye is so bad,” Dr. Ascher said. But contrast-induced renal failure occurs in up to 30% of patients with diabetes. Up to 40% of patients with preexisting renal disease have worsening renal failure after balloon angioplasty with dyes, he said.

Protection of physicians and team members also is a consideration when seeking alternatives to x-ray-guided techniques, because radiation injury is cumulative, permanent, somatic, genetic, and gonadal in onset. “When you're ready to retire, you won't be able to see,” he said.

Dr. Ascher reported the results of 470 duplex-guided balloon angioplasty procedures that he performed in a 3-year period, most—360—involving the femoropopliteal segments of the infrainguinal arteries. The rest of the cases involved infrapopliteal arterial occlusion, failing arteriovenous access fistulas and bypass grafts, infrainguinal arterial bypasses, and other indications.

Among the femoropopliteal segment cases, half of patients had diabetes, 37% had chronic renal insufficiency, and 80% had hypertension. Severe claudication was present in 63%; 65% had stenosis, and 35% had occlusion. Most patients met criteria for TransAtlantic Inter-Society Consensus (TASC) class C or D (68% and 10%, respectively), but some were class A and B (5% and 17%, respectively).

Dr. Ascher demonstrated the procedure, which involves duplex-guided ipsilateral arterial puncture and precise visualization of the tip of the wire during the entire procedure, which minimizes bleeding risk. When the wire was not easily manipulable because of multiple branches or during subintimal angioplasty, he was able to confirm, using duplex ultrasound, that it was still inside the true lumen. Stents were placed in any case where residual stenosis was greater than 40%, he said.

Technical success was achieved in 95% of cases, including 229 of 230 patients with stenosis and 104 of 122 with occlusive disease. Clinical improvement was seen in 95% of cases. One patient died of a myocardial infarction.

Among 268 patients followed for up to 6 months after angioplasty of lower extremity arteries, 10 thrombosed early (within 30 days).

All of these had TASC lesions rated as class C (6 of 185 such patients) or class D (4 of 26 such patients). A multivariant analysis found that the strongest predictor of early (30-day) and midterm (6-month) arterial thrombosis was popliteal artery volume flow of less than 100 mL/min.

Dr. Ascher also described results of 80 duplex-guided balloon angioplasties of the infrapopliteal segment that he performed.

These procedures were usually completed in less than 1 hour. Technical success was achieved in 77 of 80 cases, including 67 of 70 patients with stenosis and 9 of 10 with occlusion.

In another 49 cases, the duplex technique was used to perform infrainguinal bypass for failing grafts. There were 48 technical successes in this group, with 1 perforation by a cutting balloon repaired later by patch angioplasty, and 1 case that could not be completed due to extreme tortuosity. At 6 months, primary patency was achieved in 34 of 49 cases (69%), and all patients' limbs had been salvaged.

B-mode image shows a 6-mm balloon that is fully inflated across the superficial femoral artery origin (arrow). Images courtesy Dr. Enrico Ascher

Arrows show a balloon's blades across the severe focal stenosis in the femoral to plantar artery vein bypass graft.

The procedure involves duplex-guided ipsilateral arterial puncture and visualization of the wire tip the whole time. DR. ASCHER

LAS VEGAS — Duplex-guided balloon angioplasty provides excellent visualization and spares patients exposure to radiation and potential nephrotoxicity from contrast agents, said Dr. Enrico Ascher at the spring meeting of the American College of Surgeons.

Patients with diabetes and those with preexisting renal disease are particularly well served by the duplex approach, said Dr. Ascher, director of the vascular surgery division at Maimonides Medical Center in Brooklyn, N.Y., and professor of surgery at Mt. Sinai Medical Center in New York. However, all patients benefit from the myriad advantages of duplex-guided procedures, including multiplanar imaging and five- to sixfold magnification; the ability to view the entire vessel wall rather than just the lumen; and more precise measurement for, selection of, and placement of stents.

Furthermore, duplex techniques allow two ways of immediately assessing the adequacy of the procedure: visualization of the anatomy and hemodynamic confirmation, he said.

“I'm not here to say x-ray is bad or dye is so bad,” Dr. Ascher said. But contrast-induced renal failure occurs in up to 30% of patients with diabetes. Up to 40% of patients with preexisting renal disease have worsening renal failure after balloon angioplasty with dyes, he said.

Protection of physicians and team members also is a consideration when seeking alternatives to x-ray-guided techniques, because radiation injury is cumulative, permanent, somatic, genetic, and gonadal in onset. “When you're ready to retire, you won't be able to see,” he said.

Dr. Ascher reported the results of 470 duplex-guided balloon angioplasty procedures that he performed in a 3-year period, most—360—involving the femoropopliteal segments of the infrainguinal arteries. The rest of the cases involved infrapopliteal arterial occlusion, failing arteriovenous access fistulas and bypass grafts, infrainguinal arterial bypasses, and other indications.

Among the femoropopliteal segment cases, half of patients had diabetes, 37% had chronic renal insufficiency, and 80% had hypertension. Severe claudication was present in 63%; 65% had stenosis, and 35% had occlusion. Most patients met criteria for TransAtlantic Inter-Society Consensus (TASC) class C or D (68% and 10%, respectively), but some were class A and B (5% and 17%, respectively).

Dr. Ascher demonstrated the procedure, which involves duplex-guided ipsilateral arterial puncture and precise visualization of the tip of the wire during the entire procedure, which minimizes bleeding risk. When the wire was not easily manipulable because of multiple branches or during subintimal angioplasty, he was able to confirm, using duplex ultrasound, that it was still inside the true lumen. Stents were placed in any case where residual stenosis was greater than 40%, he said.

Technical success was achieved in 95% of cases, including 229 of 230 patients with stenosis and 104 of 122 with occlusive disease. Clinical improvement was seen in 95% of cases. One patient died of a myocardial infarction.

Among 268 patients followed for up to 6 months after angioplasty of lower extremity arteries, 10 thrombosed early (within 30 days).

All of these had TASC lesions rated as class C (6 of 185 such patients) or class D (4 of 26 such patients). A multivariant analysis found that the strongest predictor of early (30-day) and midterm (6-month) arterial thrombosis was popliteal artery volume flow of less than 100 mL/min.

Dr. Ascher also described results of 80 duplex-guided balloon angioplasties of the infrapopliteal segment that he performed.

These procedures were usually completed in less than 1 hour. Technical success was achieved in 77 of 80 cases, including 67 of 70 patients with stenosis and 9 of 10 with occlusion.

In another 49 cases, the duplex technique was used to perform infrainguinal bypass for failing grafts. There were 48 technical successes in this group, with 1 perforation by a cutting balloon repaired later by patch angioplasty, and 1 case that could not be completed due to extreme tortuosity. At 6 months, primary patency was achieved in 34 of 49 cases (69%), and all patients' limbs had been salvaged.

B-mode image shows a 6-mm balloon that is fully inflated across the superficial femoral artery origin (arrow). Images courtesy Dr. Enrico Ascher

Arrows show a balloon's blades across the severe focal stenosis in the femoral to plantar artery vein bypass graft.

The procedure involves duplex-guided ipsilateral arterial puncture and visualization of the wire tip the whole time. DR. ASCHER

LAS VEGAS — Duplex-guided balloon angioplasty provides excellent visualization and spares patients exposure to radiation and potential nephrotoxicity from contrast agents, said Dr. Enrico Ascher at the spring meeting of the American College of Surgeons.

Patients with diabetes and those with preexisting renal disease are particularly well served by the duplex approach, said Dr. Ascher, director of the vascular surgery division at Maimonides Medical Center in Brooklyn, N.Y., and professor of surgery at Mt. Sinai Medical Center in New York. However, all patients benefit from the myriad advantages of duplex-guided procedures, including multiplanar imaging and five- to sixfold magnification; the ability to view the entire vessel wall rather than just the lumen; and more precise measurement for, selection of, and placement of stents.

Furthermore, duplex techniques allow two ways of immediately assessing the adequacy of the procedure: visualization of the anatomy and hemodynamic confirmation, he said.

“I'm not here to say x-ray is bad or dye is so bad,” Dr. Ascher said. But contrast-induced renal failure occurs in up to 30% of patients with diabetes. Up to 40% of patients with preexisting renal disease have worsening renal failure after balloon angioplasty with dyes, he said.

Protection of physicians and team members also is a consideration when seeking alternatives to x-ray-guided techniques, because radiation injury is cumulative, permanent, somatic, genetic, and gonadal in onset. “When you're ready to retire, you won't be able to see,” he said.

Dr. Ascher reported the results of 470 duplex-guided balloon angioplasty procedures that he performed in a 3-year period, most—360—involving the femoropopliteal segments of the infrainguinal arteries. The rest of the cases involved infrapopliteal arterial occlusion, failing arteriovenous access fistulas and bypass grafts, infrainguinal arterial bypasses, and other indications.

Among the femoropopliteal segment cases, half of patients had diabetes, 37% had chronic renal insufficiency, and 80% had hypertension. Severe claudication was present in 63%; 65% had stenosis, and 35% had occlusion. Most patients met criteria for TransAtlantic Inter-Society Consensus (TASC) class C or D (68% and 10%, respectively), but some were class A and B (5% and 17%, respectively).

Dr. Ascher demonstrated the procedure, which involves duplex-guided ipsilateral arterial puncture and precise visualization of the tip of the wire during the entire procedure, which minimizes bleeding risk. When the wire was not easily manipulable because of multiple branches or during subintimal angioplasty, he was able to confirm, using duplex ultrasound, that it was still inside the true lumen. Stents were placed in any case where residual stenosis was greater than 40%, he said.

Technical success was achieved in 95% of cases, including 229 of 230 patients with stenosis and 104 of 122 with occlusive disease. Clinical improvement was seen in 95% of cases. One patient died of a myocardial infarction.

Among 268 patients followed for up to 6 months after angioplasty of lower extremity arteries, 10 thrombosed early (within 30 days).

All of these had TASC lesions rated as class C (6 of 185 such patients) or class D (4 of 26 such patients). A multivariant analysis found that the strongest predictor of early (30-day) and midterm (6-month) arterial thrombosis was popliteal artery volume flow of less than 100 mL/min.

Dr. Ascher also described results of 80 duplex-guided balloon angioplasties of the infrapopliteal segment that he performed.

These procedures were usually completed in less than 1 hour. Technical success was achieved in 77 of 80 cases, including 67 of 70 patients with stenosis and 9 of 10 with occlusion.

In another 49 cases, the duplex technique was used to perform infrainguinal bypass for failing grafts. There were 48 technical successes in this group, with 1 perforation by a cutting balloon repaired later by patch angioplasty, and 1 case that could not be completed due to extreme tortuosity. At 6 months, primary patency was achieved in 34 of 49 cases (69%), and all patients' limbs had been salvaged.

B-mode image shows a 6-mm balloon that is fully inflated across the superficial femoral artery origin (arrow). Images courtesy Dr. Enrico Ascher

Arrows show a balloon's blades across the severe focal stenosis in the femoral to plantar artery vein bypass graft.

The procedure involves duplex-guided ipsilateral arterial puncture and visualization of the wire tip the whole time. DR. ASCHER

The Centers for Medicare and Medicaid Services is amending its diagnostic ultrasound policy to allow coverage of Doppler monitoring of cardiac output in ventilated patients in intensive care and operative patients with a need for intraoperative fluid optimization.

The agency said that new studies had come to light that led it to reverse its previous decision against national coverage of the monitoring.

“As we developed this decision, we used the best available medical evidence—in the form of randomized controlled clinical trials—to reevaluate our position on this important noninvasive method of caring for patients in intensive care situations,” CMS Acting Administrator Leslie V. Norwalk said in a statement.

Deltex Medical Group PLC, the Chichester, England-based company that makes the monitoring equipment, petitioned CMS last year to revisit its coverage decision. According to Deltex, the earlier CMS decision was made before its device, the CardioQ, was commercially available. The CardioQ was approved by the Food and Drug Administration under the 510(k) process in 2003.

CMS agreed with Deltex that there was now sufficient evidence to support coverage. The agency found a number of prospective, randomized studies showing that when compared with standard cardiac output (CO) monitoring, patients managed with the less invasive esophageal Doppler monitoring “had adequate CO, shorter hospital length of stays … and, generally, decreased complications.”

The CardioQ system uses a disposable ultrasound probe inserted into the patient's esophagus. It determines circulating blood volume, a crucial measure during surgery or for ventilated patients in the ICU. The measure is used to guide intravenous fluid replacement and drug therapy.

The Centers for Medicare and Medicaid Services is amending its diagnostic ultrasound policy to allow coverage of Doppler monitoring of cardiac output in ventilated patients in intensive care and operative patients with a need for intraoperative fluid optimization.

The agency said that new studies had come to light that led it to reverse its previous decision against national coverage of the monitoring.

“As we developed this decision, we used the best available medical evidence—in the form of randomized controlled clinical trials—to reevaluate our position on this important noninvasive method of caring for patients in intensive care situations,” CMS Acting Administrator Leslie V. Norwalk said in a statement.

Deltex Medical Group PLC, the Chichester, England-based company that makes the monitoring equipment, petitioned CMS last year to revisit its coverage decision. According to Deltex, the earlier CMS decision was made before its device, the CardioQ, was commercially available. The CardioQ was approved by the Food and Drug Administration under the 510(k) process in 2003.

CMS agreed with Deltex that there was now sufficient evidence to support coverage. The agency found a number of prospective, randomized studies showing that when compared with standard cardiac output (CO) monitoring, patients managed with the less invasive esophageal Doppler monitoring “had adequate CO, shorter hospital length of stays … and, generally, decreased complications.”

The CardioQ system uses a disposable ultrasound probe inserted into the patient's esophagus. It determines circulating blood volume, a crucial measure during surgery or for ventilated patients in the ICU. The measure is used to guide intravenous fluid replacement and drug therapy.

The Centers for Medicare and Medicaid Services is amending its diagnostic ultrasound policy to allow coverage of Doppler monitoring of cardiac output in ventilated patients in intensive care and operative patients with a need for intraoperative fluid optimization.

The agency said that new studies had come to light that led it to reverse its previous decision against national coverage of the monitoring.

“As we developed this decision, we used the best available medical evidence—in the form of randomized controlled clinical trials—to reevaluate our position on this important noninvasive method of caring for patients in intensive care situations,” CMS Acting Administrator Leslie V. Norwalk said in a statement.

Deltex Medical Group PLC, the Chichester, England-based company that makes the monitoring equipment, petitioned CMS last year to revisit its coverage decision. According to Deltex, the earlier CMS decision was made before its device, the CardioQ, was commercially available. The CardioQ was approved by the Food and Drug Administration under the 510(k) process in 2003.

CMS agreed with Deltex that there was now sufficient evidence to support coverage. The agency found a number of prospective, randomized studies showing that when compared with standard cardiac output (CO) monitoring, patients managed with the less invasive esophageal Doppler monitoring “had adequate CO, shorter hospital length of stays … and, generally, decreased complications.”

The CardioQ system uses a disposable ultrasound probe inserted into the patient's esophagus. It determines circulating blood volume, a crucial measure during surgery or for ventilated patients in the ICU. The measure is used to guide intravenous fluid replacement and drug therapy.

WASHINGTON — Whether to use a cardiac-focused CT protocol or a triple rule-out approach for assessing acute chest pain in the emergency department depends to some degree on what your clinical suspicions are, said Dr. Charles S. White at the annual meeting of the Society of Cardiovascular Computed Tomography.

“The question here is: Do you want to focus just on the coronaries, or do you want to expand the search and look for those 85% of other causes … that we might be able to detect with the triple rule out?” said Dr. White, chief of thoracic radiology at the University of Maryland Medical Center in Baltimore.

In the cardiac-focused CT approach, the field of view is limited to the area of the coronary arteries and therefore offers better spatial resolution of these vessels than the triple rule-out approach. This approach takes about 8 seconds on average and uses less radiation and contrast. The scanning direction is craniocaudal.

With the triple rule-out approach, the intent is to image the entire thorax, allowing visualization not only of the coronary arteries but the aorta and the pulmonary arteries. This approach allows evaluation for coronary artery disease, pulmonary embolism, and aortic dissection—earning it the triple rule-out moniker.

The trade-off for this expanded field of view is decreased spatial resolution, compared with the cardiac-focused approach. This approach involves a longer scan time (15 seconds) and involves greater radiation doses and more contrast than the cardiac-focused approach does. To minimize the chance of motion defects associated with a longer scan time, the scan is performed caudocranially. Motion is not as great a concern in the upper thorax, which is imaged last.

“The bottom line, I think, in terms of protocol between cardiac and triple rule out is that it depends on your level or suspicion that the cause of chest pain might be pulmonary embolism,” said Dr. White. “When you have some level of suspicion of a pulmonary embolism, a triple rule-out study may be appropriate. If you don't, then a dedicated CT [angiography] would be the way to go.”

In the University of Maryland Medical Center's ED, “We are generally still doing triple rule-out protocols,” said Dr. White. Cardiac-only studies can be ordered by emergency physicians as well. However, in their experience, most triple rule-out patients (75%) have calcium scores of zero or close to it. Roughly 15% have significant stenosis.

There are a number of challenges associated with using the triple rule-out protocol. Getting patient cooperation can be difficult. When using 64-slice CT, however, it's not crucial to get the heart rate down below 90 beats per minute. “As long as it's a stable heart rate, a 64-slice scanner will generally get you fairly good images,” said Dr. White.

Cost also is an issue with the triple rule-out approach, as is the greater radiation dose. The amount of technical labor required also is a concern. The ideal option is to have an in-house service to read the images on a 24-hour, 7-day a week basis.

However, industry is increasingly offering options to allow for off-hour coverage, such as the ability of radiologists and cardiologists to do preliminary reviews of images wherever they are.

“The bottom line is that about 50% of studies are negative. Off-hours, those patients are fairly easy to read … and you can probably send them home,” said Dr. White. The images of the remaining patients are evaluated further the next morning.

Dr. White disclosed that he has received research support from Phillips Medical Systems.

WASHINGTON — Whether to use a cardiac-focused CT protocol or a triple rule-out approach for assessing acute chest pain in the emergency department depends to some degree on what your clinical suspicions are, said Dr. Charles S. White at the annual meeting of the Society of Cardiovascular Computed Tomography.

“The question here is: Do you want to focus just on the coronaries, or do you want to expand the search and look for those 85% of other causes … that we might be able to detect with the triple rule out?” said Dr. White, chief of thoracic radiology at the University of Maryland Medical Center in Baltimore.

In the cardiac-focused CT approach, the field of view is limited to the area of the coronary arteries and therefore offers better spatial resolution of these vessels than the triple rule-out approach. This approach takes about 8 seconds on average and uses less radiation and contrast. The scanning direction is craniocaudal.

With the triple rule-out approach, the intent is to image the entire thorax, allowing visualization not only of the coronary arteries but the aorta and the pulmonary arteries. This approach allows evaluation for coronary artery disease, pulmonary embolism, and aortic dissection—earning it the triple rule-out moniker.

The trade-off for this expanded field of view is decreased spatial resolution, compared with the cardiac-focused approach. This approach involves a longer scan time (15 seconds) and involves greater radiation doses and more contrast than the cardiac-focused approach does. To minimize the chance of motion defects associated with a longer scan time, the scan is performed caudocranially. Motion is not as great a concern in the upper thorax, which is imaged last.

“The bottom line, I think, in terms of protocol between cardiac and triple rule out is that it depends on your level or suspicion that the cause of chest pain might be pulmonary embolism,” said Dr. White. “When you have some level of suspicion of a pulmonary embolism, a triple rule-out study may be appropriate. If you don't, then a dedicated CT [angiography] would be the way to go.”

In the University of Maryland Medical Center's ED, “We are generally still doing triple rule-out protocols,” said Dr. White. Cardiac-only studies can be ordered by emergency physicians as well. However, in their experience, most triple rule-out patients (75%) have calcium scores of zero or close to it. Roughly 15% have significant stenosis.

There are a number of challenges associated with using the triple rule-out protocol. Getting patient cooperation can be difficult. When using 64-slice CT, however, it's not crucial to get the heart rate down below 90 beats per minute. “As long as it's a stable heart rate, a 64-slice scanner will generally get you fairly good images,” said Dr. White.

Cost also is an issue with the triple rule-out approach, as is the greater radiation dose. The amount of technical labor required also is a concern. The ideal option is to have an in-house service to read the images on a 24-hour, 7-day a week basis.

However, industry is increasingly offering options to allow for off-hour coverage, such as the ability of radiologists and cardiologists to do preliminary reviews of images wherever they are.

“The bottom line is that about 50% of studies are negative. Off-hours, those patients are fairly easy to read … and you can probably send them home,” said Dr. White. The images of the remaining patients are evaluated further the next morning.

Dr. White disclosed that he has received research support from Phillips Medical Systems.

WASHINGTON — Whether to use a cardiac-focused CT protocol or a triple rule-out approach for assessing acute chest pain in the emergency department depends to some degree on what your clinical suspicions are, said Dr. Charles S. White at the annual meeting of the Society of Cardiovascular Computed Tomography.

“The question here is: Do you want to focus just on the coronaries, or do you want to expand the search and look for those 85% of other causes … that we might be able to detect with the triple rule out?” said Dr. White, chief of thoracic radiology at the University of Maryland Medical Center in Baltimore.

In the cardiac-focused CT approach, the field of view is limited to the area of the coronary arteries and therefore offers better spatial resolution of these vessels than the triple rule-out approach. This approach takes about 8 seconds on average and uses less radiation and contrast. The scanning direction is craniocaudal.

With the triple rule-out approach, the intent is to image the entire thorax, allowing visualization not only of the coronary arteries but the aorta and the pulmonary arteries. This approach allows evaluation for coronary artery disease, pulmonary embolism, and aortic dissection—earning it the triple rule-out moniker.

The trade-off for this expanded field of view is decreased spatial resolution, compared with the cardiac-focused approach. This approach involves a longer scan time (15 seconds) and involves greater radiation doses and more contrast than the cardiac-focused approach does. To minimize the chance of motion defects associated with a longer scan time, the scan is performed caudocranially. Motion is not as great a concern in the upper thorax, which is imaged last.

“The bottom line, I think, in terms of protocol between cardiac and triple rule out is that it depends on your level or suspicion that the cause of chest pain might be pulmonary embolism,” said Dr. White. “When you have some level of suspicion of a pulmonary embolism, a triple rule-out study may be appropriate. If you don't, then a dedicated CT [angiography] would be the way to go.”

In the University of Maryland Medical Center's ED, “We are generally still doing triple rule-out protocols,” said Dr. White. Cardiac-only studies can be ordered by emergency physicians as well. However, in their experience, most triple rule-out patients (75%) have calcium scores of zero or close to it. Roughly 15% have significant stenosis.

There are a number of challenges associated with using the triple rule-out protocol. Getting patient cooperation can be difficult. When using 64-slice CT, however, it's not crucial to get the heart rate down below 90 beats per minute. “As long as it's a stable heart rate, a 64-slice scanner will generally get you fairly good images,” said Dr. White.

Cost also is an issue with the triple rule-out approach, as is the greater radiation dose. The amount of technical labor required also is a concern. The ideal option is to have an in-house service to read the images on a 24-hour, 7-day a week basis.

However, industry is increasingly offering options to allow for off-hour coverage, such as the ability of radiologists and cardiologists to do preliminary reviews of images wherever they are.

“The bottom line is that about 50% of studies are negative. Off-hours, those patients are fairly easy to read … and you can probably send them home,” said Dr. White. The images of the remaining patients are evaluated further the next morning.

Dr. White disclosed that he has received research support from Phillips Medical Systems.

WASHINGTON — Coronary CT angiography appears to be a less expensive alternative to myocardial perfusion SPECT imaging as an initial diagnostic screen for coronary artery disease, according to an analysis of data from two large regional health plans presented at the annual meeting of the Society of Cardiovascular Computed Tomography.

The average 12-month downstream coronary artery disease-related cost for patients who underwent coronary CT angiography (CTA) as an initial screen for CAD was $1,716 lower per patient than for those who underwent SPECT, said Dr. James K. Min of Cornell University, New York. The average cost of a nuclear study ranged from $3,000 to $4,000.

“CT [angiography] may be a potential, cost-efficient alternative to SPECT for the initial evaluation of patients with suspected coronary artery disease,” said Dr. Min.

The researchers analyzed private payer data from two large regional health plans with more than 6.5 million members from 2002 to 2005. The database included membership information, pharmacy claims, and inpatient and outpatient service claims. The researchers identified patients who underwent CTA or MP SPECT imaging as an initial diagnostic screen for CAD. Information was collected for 1 year prior to and 1 year after the test.

Only patients without known CAD were included. These were patients who did not have any CAD-related procedure codes for the previous 12 months. CTA and MP SPECT claims included only those with coronary heart disease codes.

For each patient, the researchers calculated a cardiac risk score. The score was a weighted average of several risk factors, including use of digitalis, anticoagulants, antiplatelets, ACE inhibitors, β-blockers, antihypertensive medication, and antidiabetic medications, as well as other clinical cardiac conditions. The researchers also assessed each patient's overall health status using the Charleston Comorbidity Index.

Each patient in the CTA group was matched with four patients in the SPECT group based on age, sex, and cardiac risk score. Both groups had an average age of 51 years. About two-thirds of the patients in each group (68%) were women. The average cardiac risk score was 0.20 in the CTA group and 0.19 in the SPECT group.

A total of 1,833 patients were identified who had an initial diagnostic screen with CTA; they were matched with 7,332 patients who had SPECT imaging.

In addition to a cost difference for the two modalities, the researchers noted that the use of antiplatelet therapy was greater among SPECT patients after the initial diagnostic test. There was also a trend toward greater use of ACE inhibitors and statins in the SPECT group, though this did not achieve significance.

“In terms of follow-up diagnostic tests, patients who initially underwent CT angiography were more likely to undergo nuclear stress testing in the follow-up period, while patients who underwent nuclear stress testing were more likely to undergo invasive coronary angiography,” said Dr. Min. Looking at any diagnostic test, there was an 18% relative risk reduction in patients who underwent initial coronary evaluation with CT angiography.

The researchers also looked at clinical outcomes. Patients who underwent initial SPECT imaging had a higher rate of surgical or percutaneous interventions in the follow-up period compared with those who had CTA—1.2% compared with 0.4%, respectively. “CTA patients experienced lower rates of both hospitalization as well as angina or myocardial infarction,” said Dr. Min, who disclosed that he receives research support from GE Healthcare.

“From this we tentatively conclude that compared to MP SPECT patients, patients who underwent CT as an initial diagnostic test incurred lower 12-month total coronary disease-related costs,” he said.

CTA reveals severe, diffuse, mixed plaque in the left anterior descending artery.

Multidetector CT volume rendered image shows calcification in the LAD and RCA. Photos courtesy Dr. James K. Min

WASHINGTON — Coronary CT angiography appears to be a less expensive alternative to myocardial perfusion SPECT imaging as an initial diagnostic screen for coronary artery disease, according to an analysis of data from two large regional health plans presented at the annual meeting of the Society of Cardiovascular Computed Tomography.

The average 12-month downstream coronary artery disease-related cost for patients who underwent coronary CT angiography (CTA) as an initial screen for CAD was $1,716 lower per patient than for those who underwent SPECT, said Dr. James K. Min of Cornell University, New York. The average cost of a nuclear study ranged from $3,000 to $4,000.

“CT [angiography] may be a potential, cost-efficient alternative to SPECT for the initial evaluation of patients with suspected coronary artery disease,” said Dr. Min.

The researchers analyzed private payer data from two large regional health plans with more than 6.5 million members from 2002 to 2005. The database included membership information, pharmacy claims, and inpatient and outpatient service claims. The researchers identified patients who underwent CTA or MP SPECT imaging as an initial diagnostic screen for CAD. Information was collected for 1 year prior to and 1 year after the test.

Only patients without known CAD were included. These were patients who did not have any CAD-related procedure codes for the previous 12 months. CTA and MP SPECT claims included only those with coronary heart disease codes.

For each patient, the researchers calculated a cardiac risk score. The score was a weighted average of several risk factors, including use of digitalis, anticoagulants, antiplatelets, ACE inhibitors, β-blockers, antihypertensive medication, and antidiabetic medications, as well as other clinical cardiac conditions. The researchers also assessed each patient's overall health status using the Charleston Comorbidity Index.

Each patient in the CTA group was matched with four patients in the SPECT group based on age, sex, and cardiac risk score. Both groups had an average age of 51 years. About two-thirds of the patients in each group (68%) were women. The average cardiac risk score was 0.20 in the CTA group and 0.19 in the SPECT group.

A total of 1,833 patients were identified who had an initial diagnostic screen with CTA; they were matched with 7,332 patients who had SPECT imaging.

In addition to a cost difference for the two modalities, the researchers noted that the use of antiplatelet therapy was greater among SPECT patients after the initial diagnostic test. There was also a trend toward greater use of ACE inhibitors and statins in the SPECT group, though this did not achieve significance.

“In terms of follow-up diagnostic tests, patients who initially underwent CT angiography were more likely to undergo nuclear stress testing in the follow-up period, while patients who underwent nuclear stress testing were more likely to undergo invasive coronary angiography,” said Dr. Min. Looking at any diagnostic test, there was an 18% relative risk reduction in patients who underwent initial coronary evaluation with CT angiography.

The researchers also looked at clinical outcomes. Patients who underwent initial SPECT imaging had a higher rate of surgical or percutaneous interventions in the follow-up period compared with those who had CTA—1.2% compared with 0.4%, respectively. “CTA patients experienced lower rates of both hospitalization as well as angina or myocardial infarction,” said Dr. Min, who disclosed that he receives research support from GE Healthcare.

“From this we tentatively conclude that compared to MP SPECT patients, patients who underwent CT as an initial diagnostic test incurred lower 12-month total coronary disease-related costs,” he said.

CTA reveals severe, diffuse, mixed plaque in the left anterior descending artery.

Multidetector CT volume rendered image shows calcification in the LAD and RCA. Photos courtesy Dr. James K. Min

WASHINGTON — Coronary CT angiography appears to be a less expensive alternative to myocardial perfusion SPECT imaging as an initial diagnostic screen for coronary artery disease, according to an analysis of data from two large regional health plans presented at the annual meeting of the Society of Cardiovascular Computed Tomography.

The average 12-month downstream coronary artery disease-related cost for patients who underwent coronary CT angiography (CTA) as an initial screen for CAD was $1,716 lower per patient than for those who underwent SPECT, said Dr. James K. Min of Cornell University, New York. The average cost of a nuclear study ranged from $3,000 to $4,000.

“CT [angiography] may be a potential, cost-efficient alternative to SPECT for the initial evaluation of patients with suspected coronary artery disease,” said Dr. Min.

The researchers analyzed private payer data from two large regional health plans with more than 6.5 million members from 2002 to 2005. The database included membership information, pharmacy claims, and inpatient and outpatient service claims. The researchers identified patients who underwent CTA or MP SPECT imaging as an initial diagnostic screen for CAD. Information was collected for 1 year prior to and 1 year after the test.

Only patients without known CAD were included. These were patients who did not have any CAD-related procedure codes for the previous 12 months. CTA and MP SPECT claims included only those with coronary heart disease codes.

For each patient, the researchers calculated a cardiac risk score. The score was a weighted average of several risk factors, including use of digitalis, anticoagulants, antiplatelets, ACE inhibitors, β-blockers, antihypertensive medication, and antidiabetic medications, as well as other clinical cardiac conditions. The researchers also assessed each patient's overall health status using the Charleston Comorbidity Index.

Each patient in the CTA group was matched with four patients in the SPECT group based on age, sex, and cardiac risk score. Both groups had an average age of 51 years. About two-thirds of the patients in each group (68%) were women. The average cardiac risk score was 0.20 in the CTA group and 0.19 in the SPECT group.

A total of 1,833 patients were identified who had an initial diagnostic screen with CTA; they were matched with 7,332 patients who had SPECT imaging.

In addition to a cost difference for the two modalities, the researchers noted that the use of antiplatelet therapy was greater among SPECT patients after the initial diagnostic test. There was also a trend toward greater use of ACE inhibitors and statins in the SPECT group, though this did not achieve significance.

“In terms of follow-up diagnostic tests, patients who initially underwent CT angiography were more likely to undergo nuclear stress testing in the follow-up period, while patients who underwent nuclear stress testing were more likely to undergo invasive coronary angiography,” said Dr. Min. Looking at any diagnostic test, there was an 18% relative risk reduction in patients who underwent initial coronary evaluation with CT angiography.

The researchers also looked at clinical outcomes. Patients who underwent initial SPECT imaging had a higher rate of surgical or percutaneous interventions in the follow-up period compared with those who had CTA—1.2% compared with 0.4%, respectively. “CTA patients experienced lower rates of both hospitalization as well as angina or myocardial infarction,” said Dr. Min, who disclosed that he receives research support from GE Healthcare.

“From this we tentatively conclude that compared to MP SPECT patients, patients who underwent CT as an initial diagnostic test incurred lower 12-month total coronary disease-related costs,” he said.

CTA reveals severe, diffuse, mixed plaque in the left anterior descending artery.

Multidetector CT volume rendered image shows calcification in the LAD and RCA. Photos courtesy Dr. James K. Min

SCOTTSDALE, ARIZ. — Duplex ultrasound with contrast enhancement delivered by continuous infusion shows promise in the detection of endoleaks following endovascular aneurysm repair, Dr. Ruth L. Bush said at an international congress on endovascular interventions sponsored by the Arizona Heart Institute.

“Our early results strongly suggest that contrast enhancement with a continuous infusion technique could be used as a primary diagnostic imaging modality for follow-up endograft surveillance,” possibly replacing CT as the standard for graft surveillance, said Dr. Bush of the Baylor College of Medicine, Houston.

Following endovascular aneurysm repair (EVAR), patients must be assessed periodically for sac size, stent-graft integrity, and endoleaks. CT is a fine imaging modality for this surveillance, but at the cost of substantial doses of ionizing radiation and exposure to iodinated contrast media, which can be nephrotoxic. Furthermore, CT scanning is expensive. According to some reports, more than 65% of postoperative costs following EVAR are related to CT scanning.

Unfortunately, color duplex ultrasound has been shown to have a lower sensitivity and a lower positive predictive value than CT has in this surveillance. Delivery of contrast enhancement in a bolus improves echogenicity and can even detect slow endoleaks that are not visible in CT. But the disadvantage of this technique is that bolus injection of the contrast medium allows for only a short scanning time—less than 10 minutes—so multiple injections are usually necessary. The contrast is provided by microbubbles, which must be small enough to pass through the pulmonary capillaries. The various gas microbubble contrast media are generally considered safe and to have low toxicity. However, it has proven difficult to maintain these microbubbles in the systemic circulation.

Some of these problems are avoided by continuous infusion of the contrast medium. Dr. Bush uses a syringe filled with contrast medium and normal saline and infuses the mixture at the rate of 4 cc/min to extend the scanning time to 20 minutes or more.

In a preliminary study in 20 patients, contrast-enhanced ultrasound found one type 1 endoleak and nine type 2 endoleaks. In those same patients, color duplex ultrasound found one type 1 endoleak and only four type 2 endoleaks, and CT found one type 1 endoleak and six type 2 endoleaks.

The patients' body type affected scanning time. The investigators noted a direct relationship between scanning time and body mass index.

And it's important to control scanning parameters carefully. For one thing, the syringe holding the contrast medium needs to be agitated continually to avoid breakdown of the microbubbles.

And it's necessary to optimize the harmonic imaging on the ultrasound machines, decrease the mechanical index and the compression, and adjust the focal zone to be below the aorta.

“All of this was done in an attempt to maintain the integrity of the microbubbles,” Dr. Bush said. “If you have a mechanical index turned up too high or the compression and the focal zone adjusted [imperfectly], the microbubbles would shatter and you won't get a good result.”

The learning curve for this technique is about 10–15 patients, she said.

Delivery of contrast enhancement in a bolus can even detect slow endoleaks that are not visible in CT. DR. BUSH

SCOTTSDALE, ARIZ. — Duplex ultrasound with contrast enhancement delivered by continuous infusion shows promise in the detection of endoleaks following endovascular aneurysm repair, Dr. Ruth L. Bush said at an international congress on endovascular interventions sponsored by the Arizona Heart Institute.

“Our early results strongly suggest that contrast enhancement with a continuous infusion technique could be used as a primary diagnostic imaging modality for follow-up endograft surveillance,” possibly replacing CT as the standard for graft surveillance, said Dr. Bush of the Baylor College of Medicine, Houston.

Following endovascular aneurysm repair (EVAR), patients must be assessed periodically for sac size, stent-graft integrity, and endoleaks. CT is a fine imaging modality for this surveillance, but at the cost of substantial doses of ionizing radiation and exposure to iodinated contrast media, which can be nephrotoxic. Furthermore, CT scanning is expensive. According to some reports, more than 65% of postoperative costs following EVAR are related to CT scanning.

Unfortunately, color duplex ultrasound has been shown to have a lower sensitivity and a lower positive predictive value than CT has in this surveillance. Delivery of contrast enhancement in a bolus improves echogenicity and can even detect slow endoleaks that are not visible in CT. But the disadvantage of this technique is that bolus injection of the contrast medium allows for only a short scanning time—less than 10 minutes—so multiple injections are usually necessary. The contrast is provided by microbubbles, which must be small enough to pass through the pulmonary capillaries. The various gas microbubble contrast media are generally considered safe and to have low toxicity. However, it has proven difficult to maintain these microbubbles in the systemic circulation.

Some of these problems are avoided by continuous infusion of the contrast medium. Dr. Bush uses a syringe filled with contrast medium and normal saline and infuses the mixture at the rate of 4 cc/min to extend the scanning time to 20 minutes or more.

In a preliminary study in 20 patients, contrast-enhanced ultrasound found one type 1 endoleak and nine type 2 endoleaks. In those same patients, color duplex ultrasound found one type 1 endoleak and only four type 2 endoleaks, and CT found one type 1 endoleak and six type 2 endoleaks.

The patients' body type affected scanning time. The investigators noted a direct relationship between scanning time and body mass index.

And it's important to control scanning parameters carefully. For one thing, the syringe holding the contrast medium needs to be agitated continually to avoid breakdown of the microbubbles.

And it's necessary to optimize the harmonic imaging on the ultrasound machines, decrease the mechanical index and the compression, and adjust the focal zone to be below the aorta.

“All of this was done in an attempt to maintain the integrity of the microbubbles,” Dr. Bush said. “If you have a mechanical index turned up too high or the compression and the focal zone adjusted [imperfectly], the microbubbles would shatter and you won't get a good result.”

The learning curve for this technique is about 10–15 patients, she said.

Delivery of contrast enhancement in a bolus can even detect slow endoleaks that are not visible in CT. DR. BUSH

SCOTTSDALE, ARIZ. — Duplex ultrasound with contrast enhancement delivered by continuous infusion shows promise in the detection of endoleaks following endovascular aneurysm repair, Dr. Ruth L. Bush said at an international congress on endovascular interventions sponsored by the Arizona Heart Institute.

“Our early results strongly suggest that contrast enhancement with a continuous infusion technique could be used as a primary diagnostic imaging modality for follow-up endograft surveillance,” possibly replacing CT as the standard for graft surveillance, said Dr. Bush of the Baylor College of Medicine, Houston.

Following endovascular aneurysm repair (EVAR), patients must be assessed periodically for sac size, stent-graft integrity, and endoleaks. CT is a fine imaging modality for this surveillance, but at the cost of substantial doses of ionizing radiation and exposure to iodinated contrast media, which can be nephrotoxic. Furthermore, CT scanning is expensive. According to some reports, more than 65% of postoperative costs following EVAR are related to CT scanning.

Unfortunately, color duplex ultrasound has been shown to have a lower sensitivity and a lower positive predictive value than CT has in this surveillance. Delivery of contrast enhancement in a bolus improves echogenicity and can even detect slow endoleaks that are not visible in CT. But the disadvantage of this technique is that bolus injection of the contrast medium allows for only a short scanning time—less than 10 minutes—so multiple injections are usually necessary. The contrast is provided by microbubbles, which must be small enough to pass through the pulmonary capillaries. The various gas microbubble contrast media are generally considered safe and to have low toxicity. However, it has proven difficult to maintain these microbubbles in the systemic circulation.

Some of these problems are avoided by continuous infusion of the contrast medium. Dr. Bush uses a syringe filled with contrast medium and normal saline and infuses the mixture at the rate of 4 cc/min to extend the scanning time to 20 minutes or more.

In a preliminary study in 20 patients, contrast-enhanced ultrasound found one type 1 endoleak and nine type 2 endoleaks. In those same patients, color duplex ultrasound found one type 1 endoleak and only four type 2 endoleaks, and CT found one type 1 endoleak and six type 2 endoleaks.

The patients' body type affected scanning time. The investigators noted a direct relationship between scanning time and body mass index.

And it's important to control scanning parameters carefully. For one thing, the syringe holding the contrast medium needs to be agitated continually to avoid breakdown of the microbubbles.

And it's necessary to optimize the harmonic imaging on the ultrasound machines, decrease the mechanical index and the compression, and adjust the focal zone to be below the aorta.

“All of this was done in an attempt to maintain the integrity of the microbubbles,” Dr. Bush said. “If you have a mechanical index turned up too high or the compression and the focal zone adjusted [imperfectly], the microbubbles would shatter and you won't get a good result.”

The learning curve for this technique is about 10–15 patients, she said.

Delivery of contrast enhancement in a bolus can even detect slow endoleaks that are not visible in CT. DR. BUSH

ORLANDO — Echocardiography overestimates the true prevalence of primary pulmonary hypertension in hemodialysis patients with end-stage renal disease, according to a study presented at a meeting sponsored by the National Kidney Foundation.

For this reason, hemodialysis patients with echocardiographic evidence of pulmonary artery hypertension (PAH) should undergo right heart catheterization for confirmation, Dr. Ifeanyi Isaiah and colleagues, of Temple University, Philadelphia, wrote in a poster.

The reported prevalence of PAH in hemodialysis patients ranges from 27% to 40%, but these numbers are based on studies that relied exclusively on echocardiographic estimates of pulmonary arterial pressures to make the diagnosis.

The more accurate way of making the diagnosis is with right heart catheterization, Dr. Isaiah and colleagues wrote.

To establish the true prevalence of PAH in this population, the investigators conducted a retrospective, observational analysis of all echocardiographic and right heart catheterization studies done in their outpatient hemodialysis unit from January 2000 to December 2006.

Of the 502 patients included in the analysis, the majority (439 patients, or 87.5%) had undergone echocardiography. Pulmonary arterial pressure greater than 40 mm Hg, suggesting the presence ofPAH, was documented in 127 of the echocardiography patients (28.9%).

Data for right heart catheterization, which were available for 22 of these 127 patients, showed that 11 (50%) of them had elevated pulmonary arterial pressure.

Although the results showed that pulmonary hypertension may be overestimated, the study also “confirms a higher prevalence of pulmonary hypertension in end-stage renal disease patients receiving hemodialysis than [in] the general population,” the investigators wrote.

In addition to providing a more accurate diagnosis of PAH in hemodialysis patients, right heart catheterization is valuable in distinguishing those patients whose elevated pulmonary pressure results from heart failure from those who have isolated PAH with no heart failure, they added.

ORLANDO — Echocardiography overestimates the true prevalence of primary pulmonary hypertension in hemodialysis patients with end-stage renal disease, according to a study presented at a meeting sponsored by the National Kidney Foundation.

For this reason, hemodialysis patients with echocardiographic evidence of pulmonary artery hypertension (PAH) should undergo right heart catheterization for confirmation, Dr. Ifeanyi Isaiah and colleagues, of Temple University, Philadelphia, wrote in a poster.

The reported prevalence of PAH in hemodialysis patients ranges from 27% to 40%, but these numbers are based on studies that relied exclusively on echocardiographic estimates of pulmonary arterial pressures to make the diagnosis.

The more accurate way of making the diagnosis is with right heart catheterization, Dr. Isaiah and colleagues wrote.

To establish the true prevalence of PAH in this population, the investigators conducted a retrospective, observational analysis of all echocardiographic and right heart catheterization studies done in their outpatient hemodialysis unit from January 2000 to December 2006.

Of the 502 patients included in the analysis, the majority (439 patients, or 87.5%) had undergone echocardiography. Pulmonary arterial pressure greater than 40 mm Hg, suggesting the presence ofPAH, was documented in 127 of the echocardiography patients (28.9%).

Data for right heart catheterization, which were available for 22 of these 127 patients, showed that 11 (50%) of them had elevated pulmonary arterial pressure.

Although the results showed that pulmonary hypertension may be overestimated, the study also “confirms a higher prevalence of pulmonary hypertension in end-stage renal disease patients receiving hemodialysis than [in] the general population,” the investigators wrote.

In addition to providing a more accurate diagnosis of PAH in hemodialysis patients, right heart catheterization is valuable in distinguishing those patients whose elevated pulmonary pressure results from heart failure from those who have isolated PAH with no heart failure, they added.

ORLANDO — Echocardiography overestimates the true prevalence of primary pulmonary hypertension in hemodialysis patients with end-stage renal disease, according to a study presented at a meeting sponsored by the National Kidney Foundation.

For this reason, hemodialysis patients with echocardiographic evidence of pulmonary artery hypertension (PAH) should undergo right heart catheterization for confirmation, Dr. Ifeanyi Isaiah and colleagues, of Temple University, Philadelphia, wrote in a poster.

The reported prevalence of PAH in hemodialysis patients ranges from 27% to 40%, but these numbers are based on studies that relied exclusively on echocardiographic estimates of pulmonary arterial pressures to make the diagnosis.

The more accurate way of making the diagnosis is with right heart catheterization, Dr. Isaiah and colleagues wrote.

To establish the true prevalence of PAH in this population, the investigators conducted a retrospective, observational analysis of all echocardiographic and right heart catheterization studies done in their outpatient hemodialysis unit from January 2000 to December 2006.

Of the 502 patients included in the analysis, the majority (439 patients, or 87.5%) had undergone echocardiography. Pulmonary arterial pressure greater than 40 mm Hg, suggesting the presence ofPAH, was documented in 127 of the echocardiography patients (28.9%).

Data for right heart catheterization, which were available for 22 of these 127 patients, showed that 11 (50%) of them had elevated pulmonary arterial pressure.

Although the results showed that pulmonary hypertension may be overestimated, the study also “confirms a higher prevalence of pulmonary hypertension in end-stage renal disease patients receiving hemodialysis than [in] the general population,” the investigators wrote.

In addition to providing a more accurate diagnosis of PAH in hemodialysis patients, right heart catheterization is valuable in distinguishing those patients whose elevated pulmonary pressure results from heart failure from those who have isolated PAH with no heart failure, they added.