Invited commentary

The treatment of infrarenal aortic aneurysm (AAA) in the high-risk patient remains a challenge. The clinical introduction of endovascular aneurysm repair (EVAR) offers the benefits of a less invasive technique that was originally intended to expand treatment to patients previously deemed not surgical candidates.

During the last decade, many single-center and registry series have consistently demonstrated a perioperative mortality and morbidity benefit of EVAR compared with conventional open repair (COR). Subgroup analyses of the high-risk patient cohorts have shown a similar benefit of EVAR over COR. What have been missing from the literature are uniformity, objectivity, and a precise definition of what constitutes a high-risk patient. Scoring systems have been proposed for COR, but in general, they do not apply to high-risk patients.1 Furthermore, none of the scoring systems for high-risk patients treated with EVAR have been validated.

A recently published randomized clinical trial of high-risk patients (EVAR 2) comparing EVAR with medical follow-up showed a high perioperative mortality (9%) in the treatment arm and no survival advantage at 4 years between EVAR and the medical follow-up arm.2 Some concerns have been raised about whether the results of this randomized clinical trial should be extrapolated to all “unfit-for-surgery” AAA patients. A high mortality in the EVAR randomized group and a low mortality of EVAR in the no-treatment group who crossed over to EVAR has raised questions about the validity of the conclusions in this trial.

Bush and colleagues evaluate the results of EVAR versus COR in the high-risk patients in the National Surgical Quality Improvement Program, a large, national, validated, highly audited database. The lower 30-day and 1-year all-cause mortality in the EVAR compared with the COR group concurs with the recently published Society for Vascular Surgery Outcomes Committee’s analysis of the high-risk patients in the investigational device exemption United States Food and Drug Administration EVAR trials.3 Bush and colleagues attempt to further stratify the results of the high-risk population by separately analyzing the American Society of Anesthesiologists class 4 subgroup. Although not statistically significant, EVAR also demonstrated a perioperative and 1-year survival benefit over open repair.

Most investigators agree that some high-risk patients do not benefit from either COR or EVAR. The objective identification of those patients remains a great challenge, primarily because of the many variables to consider. The international vascular community should come together to establish and validate a scoring system with objective definitions that reproducibly predict outcomes in high-risk patients with AAA.