November 21st, 2012

What’s The Best Treatment For Abdominal Aortic Aneurysm?

Endovascular repair of AAA (abdominal aortic aneurysm) gained enthusiastic acceptance after initial results from three trials (EVAR 1, DREAM, and OVER) found an early survival advantage for endovascular repair compared to open repair. Some of the enthusiasm waned, however, after long-term results from the first two trials found no difference in survival between the groups after the first two years. Now the results of the third trial, the Open versus Endovascular Repair (OVER) Veterans Affairs Cooperative Study Group,  have been published in the New England Journal of Medicine. and these confirm the pattern found in the other trials.

The trial randomized 881 patients with asymptomatic AAA who were eligible for either approach. Although in the early years of the trial endovascular repair was superior to open repair, after a mean followup of  5.2 years there were no significant differences in mortality between the two groups, with the same number of deaths (146) deaths occurring in each. Here are the hazard ratios for endovascular repair:

  • at 5.2 years: 0.97, 95% CI 0.77 – 1.22; P=0.81
  • at 3 years: 0.72, 95% CI, 0.51 – 1.00; P=0.05
  • at 2 years: 0.63, CI 0.40-0.98; P=0.04

Summarizing their findings, the OVER investigators wrote that the two procedures “resulted in similar long-term survival. The perioperative survival advantage with endovascular repair was sustained for several years, but rupture after repair remained a concern. Endovascular repair led to increased long-term survival among younger patients but not among older patients, for whom a greater benefit from the endovascular approach had been expected.”

In an accompanying editorial, Joshua Beckman places OVER within the context of EVAR 1 and DREAM, and points out that “the results of these three clinical trials” have been “incredibly consistent.” All three trials found “an upfront reduction in mortality with catch-up later.” With no significant differences in mortality between the procedures, “patients can weigh the value of open repair, a major operation with greater upfront morbidity and mortality, against that of endovascular repair, with its lower early-event rate but the need for indefinite radiologic surveillance.”

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