Duplex Ultrasound Looks Safe For Post-EVAR Surveillance

SAN DIEGO — Postendovascular aneurysm repair surveillance, with color flow duplex ultrasound only, is a safe alternative to the current standard practice of follow-up CT with contrast, results from a single-center study showed.

After endovascular aneurysm repair (EVAR), “CT follow-up is associated with significant risk, including increased cost, contrast nephropathy, contrast allergy, and radiation exposure,” Dr. Rabih A. Chaer said at the Vascular Annual Meeting. “Alternative follow-up methods have been proposed, including color flow duplex ultrasound, MRI, and contrast-enhanced ultrasound. Of all these modalities, it's clear that simple color flow duplex ultrasound is the most readily available, the cheapest, and the least invasive.”

He and his associates in the division of vascular surgery at the University of Pittsburgh Medical Center studied 184 patients who were switched to color flow duplex ultrasound (CDU) surveillance in 2003 as an alternative to CT. Selective CT scanning was used only for new endoleaks or for patients who presented with an enlarging abdominal aortic aneurysm (AAA) sac. Only patients with at least 1 year of follow-up were included.

Criteria for switch to CDU included patients with a residual AAA sac of 4 cm or less anytime after the first year of follow-up, patients with a stable AAA sac size for 2 years, or patients with a stable type II endoleak for 2 years. The average CDU study duration was 20 minutes. The researchers used a GE Logiq 9 machine with a 3.5-MHz curve probe.

Of the 184 patients, 13 had an active stable type II endoleak, 23 had a prior endoleak that was treated or that resolved spontaneously. The mean follow-up on CDU was 24 months. Of the 184 grafts, 76 were Ancure, 58 were Zenith, 39 were Excluder, 7 were AneuRx, and 4 were Lifepath.

Dr. Chaer reported that there were three new endoleaks detected on CDU follow-up, all in patients who received an Ancure graft. Only one patient presented with sac enlargement. “One type II endoleak was detected, but this spontaneously resolved at 3 months,” he said. “There were two distal type I endoleaks that were treated with limb extension.”

CDU identified two patients (one with an Ancure and one with an AneruRx graft) who had an increase in their AAA sac size, yet no endoleak was detected. No endoleak was seen on CT scan, but when both patients underwent angiograms, a distal type I endoleak was detected in one patient.

There were no ruptures or graft occlusions observed during the follow-up period. Eight patients died. One was an aneurysm-related death following an Ancure explantation for infection that occurred 4 years post EVAR; two were related to malignancy, and five were related to acute myocardial infarctions.

The cumulative freedom from secondary intervention after the switch to CDU was 98% at 4 years.

In order to determine the applicability of the switch criteria for a full cohort of EVAR patients, the researchers examined 196 consecutive EVAR patients in 2004. Of these, 86 (44%) had been switched to CDU surveillance, whereas the remaining 110 were still followed with CT scan. At the 6-month follow-up, only 1.5% of patients followed with CT scan met the current criteria for the switch to CDU-only surveillance. But the proportion at 1, 2, and 3 years was 55%, 86%, and 97%, respectively.

“CDU-only surveillance is safe and can be initiated early after treatment on patients with a shrinking or a stable AAA sac,” he concluded. “Most patients treated with EVAR are eligible for this modality. After the 1 year follow-up, we do recommend that CT scanning should only be selectively utilized in patients treated with EVAR. This policy should result in cost-saving advantages and avoid the complications associated with CT.”

Dr. Chaer disclosed he had no relevant conflicts.

SAN DIEGO — Postendovascular aneurysm repair surveillance, with color flow duplex ultrasound only, is a safe alternative to the current standard practice of follow-up CT with contrast, results from a single-center study showed.

After endovascular aneurysm repair (EVAR), “CT follow-up is associated with significant risk, including increased cost, contrast nephropathy, contrast allergy, and radiation exposure,” Dr. Rabih A. Chaer said at the Vascular Annual Meeting. “Alternative follow-up methods have been proposed, including color flow duplex ultrasound, MRI, and contrast-enhanced ultrasound. Of all these modalities, it's clear that simple color flow duplex ultrasound is the most readily available, the cheapest, and the least invasive.”

He and his associates in the division of vascular surgery at the University of Pittsburgh Medical Center studied 184 patients who were switched to color flow duplex ultrasound (CDU) surveillance in 2003 as an alternative to CT. Selective CT scanning was used only for new endoleaks or for patients who presented with an enlarging abdominal aortic aneurysm (AAA) sac. Only patients with at least 1 year of follow-up were included.

Criteria for switch to CDU included patients with a residual AAA sac of 4 cm or less anytime after the first year of follow-up, patients with a stable AAA sac size for 2 years, or patients with a stable type II endoleak for 2 years. The average CDU study duration was 20 minutes. The researchers used a GE Logiq 9 machine with a 3.5-MHz curve probe.

Of the 184 patients, 13 had an active stable type II endoleak, 23 had a prior endoleak that was treated or that resolved spontaneously. The mean follow-up on CDU was 24 months. Of the 184 grafts, 76 were Ancure, 58 were Zenith, 39 were Excluder, 7 were AneuRx, and 4 were Lifepath.

Dr. Chaer reported that there were three new endoleaks detected on CDU follow-up, all in patients who received an Ancure graft. Only one patient presented with sac enlargement. “One type II endoleak was detected, but this spontaneously resolved at 3 months,” he said. “There were two distal type I endoleaks that were treated with limb extension.”

CDU identified two patients (one with an Ancure and one with an AneruRx graft) who had an increase in their AAA sac size, yet no endoleak was detected. No endoleak was seen on CT scan, but when both patients underwent angiograms, a distal type I endoleak was detected in one patient.

There were no ruptures or graft occlusions observed during the follow-up period. Eight patients died. One was an aneurysm-related death following an Ancure explantation for infection that occurred 4 years post EVAR; two were related to malignancy, and five were related to acute myocardial infarctions.

The cumulative freedom from secondary intervention after the switch to CDU was 98% at 4 years.

In order to determine the applicability of the switch criteria for a full cohort of EVAR patients, the researchers examined 196 consecutive EVAR patients in 2004. Of these, 86 (44%) had been switched to CDU surveillance, whereas the remaining 110 were still followed with CT scan. At the 6-month follow-up, only 1.5% of patients followed with CT scan met the current criteria for the switch to CDU-only surveillance. But the proportion at 1, 2, and 3 years was 55%, 86%, and 97%, respectively.

“CDU-only surveillance is safe and can be initiated early after treatment on patients with a shrinking or a stable AAA sac,” he concluded. “Most patients treated with EVAR are eligible for this modality. After the 1 year follow-up, we do recommend that CT scanning should only be selectively utilized in patients treated with EVAR. This policy should result in cost-saving advantages and avoid the complications associated with CT.”

Dr. Chaer disclosed he had no relevant conflicts.

SAN DIEGO — Postendovascular aneurysm repair surveillance, with color flow duplex ultrasound only, is a safe alternative to the current standard practice of follow-up CT with contrast, results from a single-center study showed.

After endovascular aneurysm repair (EVAR), “CT follow-up is associated with significant risk, including increased cost, contrast nephropathy, contrast allergy, and radiation exposure,” Dr. Rabih A. Chaer said at the Vascular Annual Meeting. “Alternative follow-up methods have been proposed, including color flow duplex ultrasound, MRI, and contrast-enhanced ultrasound. Of all these modalities, it's clear that simple color flow duplex ultrasound is the most readily available, the cheapest, and the least invasive.”

He and his associates in the division of vascular surgery at the University of Pittsburgh Medical Center studied 184 patients who were switched to color flow duplex ultrasound (CDU) surveillance in 2003 as an alternative to CT. Selective CT scanning was used only for new endoleaks or for patients who presented with an enlarging abdominal aortic aneurysm (AAA) sac. Only patients with at least 1 year of follow-up were included.

Criteria for switch to CDU included patients with a residual AAA sac of 4 cm or less anytime after the first year of follow-up, patients with a stable AAA sac size for 2 years, or patients with a stable type II endoleak for 2 years. The average CDU study duration was 20 minutes. The researchers used a GE Logiq 9 machine with a 3.5-MHz curve probe.

Of the 184 patients, 13 had an active stable type II endoleak, 23 had a prior endoleak that was treated or that resolved spontaneously. The mean follow-up on CDU was 24 months. Of the 184 grafts, 76 were Ancure, 58 were Zenith, 39 were Excluder, 7 were AneuRx, and 4 were Lifepath.

Dr. Chaer reported that there were three new endoleaks detected on CDU follow-up, all in patients who received an Ancure graft. Only one patient presented with sac enlargement. “One type II endoleak was detected, but this spontaneously resolved at 3 months,” he said. “There were two distal type I endoleaks that were treated with limb extension.”

CDU identified two patients (one with an Ancure and one with an AneruRx graft) who had an increase in their AAA sac size, yet no endoleak was detected. No endoleak was seen on CT scan, but when both patients underwent angiograms, a distal type I endoleak was detected in one patient.

There were no ruptures or graft occlusions observed during the follow-up period. Eight patients died. One was an aneurysm-related death following an Ancure explantation for infection that occurred 4 years post EVAR; two were related to malignancy, and five were related to acute myocardial infarctions.

The cumulative freedom from secondary intervention after the switch to CDU was 98% at 4 years.

In order to determine the applicability of the switch criteria for a full cohort of EVAR patients, the researchers examined 196 consecutive EVAR patients in 2004. Of these, 86 (44%) had been switched to CDU surveillance, whereas the remaining 110 were still followed with CT scan. At the 6-month follow-up, only 1.5% of patients followed with CT scan met the current criteria for the switch to CDU-only surveillance. But the proportion at 1, 2, and 3 years was 55%, 86%, and 97%, respectively.

“CDU-only surveillance is safe and can be initiated early after treatment on patients with a shrinking or a stable AAA sac,” he concluded. “Most patients treated with EVAR are eligible for this modality. After the 1 year follow-up, we do recommend that CT scanning should only be selectively utilized in patients treated with EVAR. This policy should result in cost-saving advantages and avoid the complications associated with CT.”

Dr. Chaer disclosed he had no relevant conflicts.