Study Compares Long-Term Outcomes of EVAR and Open Repair for AAA in the Medicare Population

July 23, 2015—Compared to open repair, endovascular aneurysm repair (EVAR) of abdominal aortic aneurysm (AAA) was associated with a substantial early survival advantage that gradually decreased over time, according to a study published by Marc L. Schermerhorn, MD, et al in The New England Journal of Medicine (NEJM; 2015;373:328–333). The National Institutes of Health funded the study.

Previously published randomized trials and observational studies have shown that perioperative morbidity and mortality are lower with EVAR for AAA than with open repair, but the survival benefit is not sustained. In addition, concerns have been raised about the long-term risk of aneurysm rupture or the need for reintervention after EVAR.

As summarized in NEJM, the study assessed perioperative and long-term survival, reinterventions, and complications after EVAR as compared with open repair of AAA in propensity-score–matched cohorts of Medicare beneficiaries who underwent repair during the period from 2001 through 2008 and were followed through 2009.

The investigators identified 39,966 matched pairs of patients who had undergone either open repair or endovascular repair. The overall perioperative mortality was 1.6% with EVAR versus 5.2% with open repair. From 2001 through 2008, perioperative mortality decreased by 0.8 percentage points among patients who underwent EVAR and by 0.6 percentage points among patients who underwent open repair. The rate of conversion from EVAR to open repair decreased from 2.2% in 2001 to 0.3% in 2008. 

The rate of survival was significantly higher after EVAR than after open repair through the first 3 years of follow-up, after which time, the rates of survival were similar. Through 8 years of follow-up, interventions related to the management of the aneurysm or its complications were more common after EVAR, whereas interventions for complications related to laparotomy were more common after open repair. 

Aneurysm rupture occurred in 5.4% of patients after EVAR versus 1.4% of patients after open repair through 8 years of follow-up. Over time, the rate of total reinterventions at 2 years after EVAR decreased from 10.4% among patients who underwent procedures in 2001 to 9.1% among patients who underwent procedures in 2007, reported the investigators in NEJM.