April 27, 2010 — While repair of large abdominal aortic aneurysms (AAA's) is well accepted, randomized clinical trials have failed to demonstrate benefit for early surgical repair of small aneurysms over surveillance, according to researchers from New York-Presbyterian Hospital in New York. Details of their study appear in the May issue of the Journal of Vascular Surgery, published by the Society for Vascular Surgery.
"Even though endovascular repair has been demonstrated to be safer than open surgical repair in patients with large aneurysms, our team of researchers wanted to do a randomized trial of early endovascular repair vs. surveillance in patients with small aneurysms," said co-author Kenneth Ouriel, M.D., senior vice president and chief of international operations at the hospital.
"Our findings showed that both early treatment with endovascular repair and rigorous surveillance with selective aneurysm treatment as indicated, appear to be safe alternatives for patients with small abdominal aneurysms, protecting the patient from rupture or aneurysm-related death for at least three years," said Ouriel.
A total of 728 patients with small infrarenal aneurysms (4.0 to 5.0 centimeters in diameter) were found on computed tomography (CT) scan up to three months prior after a screening of 4,665 patients. The two groups were randomly assigned to either early endovascular repair (366) or ultrasound surveillance (362). Of the repair patients, 322 had an endograft while four had open surgery (99.7 percent success rate). With regard to the ultrasound surveillance group, 109 had to have an endograft and three had open surgery; 70.6 percent of these procedures were due to the growth of the AAA.
The mean age of the patients was 71 (plus or minus eight years) and approximately 13 percent were women. Rupture or aneurysm-related death and overall mortality were compared in the two groups during a mean (± SD) follow-up of 20 ± 12 months (range, 0 to 41 months).
There were 15 deaths in each group (4.1 percent) and the unadjusted hazard ratio for mortality after early endovascular repair was 1.01. Aneurysm rupture or aneurysm-related death occurred in two patients in each group (0.6 percent). The unadjusted hazard ratio was 0.99 for early endovascular repair.
"Treatment decisions for an individual patient are based on weighing the estimated risk of rupture against the risk or repair estimated risk of death from treatment," he said. "In our study we sought to clarify the distinction between small and large aneurysms. Until longer follow-up data from this study are available, early treatment with EVAR and image-based surveillance, and aneurysm treatment as clinically indicated, both appear to be safe alternatives for patients with small aneurysms of 4.0 to 5.0 cm," Ouriel added.
Researchers noted that this recommendation is based on early data that might change as longer-term data accrues and that the findings must be taken in the context of the very low operative mortality rate after EVAR performed by the experienced trial surgeons and the diligence of the follow-up in the surveiled patients.
"In addition, patients who are non-compliant with imaging protocols comprise a particularly challenging subgroup for whom neither surveillance with selected repair, endovascular repair, and not even open surgery provide a safe option," Ouriel said.
Decisions should be individualized and based on the size of the aneurysm, the medical condition of the patient, the likelihood of patient following a rigorous surveillance protocol and the surgeon's expertise, he added.