Although some vascular surgeons are convinced that endovascular aneurysm repair (EVAR) is superior to open repair for the treatment of ruptured abdominal aortic aneurysms (rAAAs), the issue remains controversial. The naysayers for the superiority of EVAR in this setting claim that all data showing superior outcomes for EVAR are flawed by patient selection, and they demand level 1 evidence from randomized comparisons of EVAR and open repair.
Three such randomized controlled trials (RCTs) have recently been published or have had their results presented: the AJAX or Amsterdam (Dutch) trial,1 the ECAR or French trial,2 and the IMPROVE or U.K. trial.3 All three trials concluded that 30-day mortality outcomes after EVAR are no better than those after open repair. However, in these three trials, this conclusion is rendered unjustified or misleading because of serious flaws or misinterpretation of the trial data. Let us examine the specifics.
The AJAX and ECAR trials randomized small numbers (116 and 107, respectively) of patients and had the serious flaw of excluding hypotensive or unstable rAAA patients. Such high-risk patients are precisely the ones who are most likely to have better outcomes with EVAR than with open repair. Therefore, exclusion of these high-risk patients precludes these trials from demonstrating the advantage that EVAR might have in the overall population of patients with rAAAs. In addition, both these trials may have used, in a suboptimal fashion, three adjuncts generally believed to improve EVAR outcomes.
Better usage of fluid restriction (hypotensive hemostasis), supra-aortic balloon control and open abdomen treatment of abdominal compartment syndrome might have further improved the EVAR outcomes in both trials.
In contrast to these two smaller RCTs, the larger U.K. IMPROVE trial was conducted in 30 high-volume centers. Although 652 possible rAAA patients were excluded for various reasons, the trialists did randomize 613 patients with a diagnosis of rAAA to either an endovascular strategy (316 patients) or open repair (297 patients).
Patients were randomized before CT scans were performed. The 30-day mortality in the endovascular strategy group was 35%; in the open repair group, it was 37%. Obviously, there was no significant difference, and a primary conclusion of the main IMPROVE trial article was “A strategy of endovascular repair was not associated with significant reduction in 30-day mortality.” This was paraphrased in various news report headlines as, “No Difference Between Endovascular and Open Repair.”
However, the detailed data from the IMPROVE trial must be examined closely to see why these conclusions are misleading. Of the patients randomized to the endovascular strategy group, only 154 (about half) actually underwent EVAR; 112 had an open repair and 17 had no treatment. The 30-day mortality in this group was 27% for those treated by EVAR and 38% for those treated by open repair. Of the patients randomized to the open repair group, 36 actually had EVAR, 220 had open repair, and 19 had no treatment.
The 30-day mortality in this open repair group was 22% for those undergoing EVAR and 37% for those undergoing open repair. Overall in the two randomized groups, taken together, the 30-day mortality for rAAA patients actually treated by EVAR was 25% and for those actually treated by Open Repair, it was 38%.
Clearly the conclusion of the IMPROVE trial should have been, in patients with an rAAA, if they can be treated by EVAR, their 30-day survival will be superior. If one adds to this the fact that patients undergoing EVAR are less likely to receive no treatment, the conclusion is inescapable: EVAR is superior to open repair for the treatment of patients with rAAAs.
Thus, those treating rAAA patients must learn how to do EVAR in this setting, including acquiring expertise in all the adjuncts and strategies that can improve EVAR outcomes in such patients. We do not need further RCTs to confuse the issue any more.
1. Ann. Surg. 2013;258:248-56.
Dr. Veith is professor of surgery at New York University Medical Center and the Cleveland Clinic. He is an associate medical editor for Vascular Specialist. The ideas and opinions expressed in Vascular Specialist do not necessarily reflect those of the Society or publisher.