1Jeffrey H. Freihage, MD, 2Aravinda Nanjundappa, MD, RVT, 3Pranab Das, MD, 1Robert S. Dieter, MD, RVT Author Affiliations: From 1Loyola University, Maywood, Illinois, 2East Carolina University, Greenville, North Carolina, and 3Memphis Medical Center, Memphis, Tennessee. Correspondence: Robert S. Dieter, MD, RVT, Assistant Professor of Medicine, Vascular and Endovascular Medicine, Interventional Cardiology, Loyola University, 2160 S. First Ave., Maywood, IL 60153. E-mail: email@example.com. Disclosure: The authors report no financial relationships or conflicts of interest regarding the content therein. ___________________________ Endovascular repair of abdominal aortic aneurysms (AAA) has become an accepted and often preferred method of therapy. However, the influence of endograft design (i.e., bifurcated versus aorto-uni-iliac [AUI]) on outcomes is unknown. In this issue of Vascular Disease Management, the authors of the article “Whether Bifurcated Endografts Perform Better Than AUI” attempt to give insight into the issue of graft design on long-term outcomes.1 In their study, they retrospectively compare the outcomes of patients in the Eurostar database and their own database who had received either the bifurcated design versus the AUI design. In this nonrandomized retrospective review, the authors found that patients who received an AUI device were more likely to be older, have larger aneurysms, be unfit for open repair, and have occlusion of a common iliac artery. Despite the differences in patient demographics, both stent designs performed equally well in terms of graft-related complications: endoleak rate, graft migration, graft reintervention, aneurysm rupture, and pseudoaneurysm formation during short- and long-term follow up. Importantly, the authors discovered in both the Eurostar series and their own personal series that patients who underwent repair with an AUI device had a significantly higher mortality during long-term follow up, relative to those who underwent repair with the bifurcated design. Most importantly, the aneurysm related mortality after 7 years was similar between both stent design groups. The retrospective review presented in this issue gives important data on the utility of the AUI device for the treatment of AAA. Importantly, the authors report that relative to those who receive a bifurcated stent design, the rate of graft-related complications is quite similar, despite insertion of the AUI device in an older patient population with more comorbidities and larger aneurysms. Although, this study lends evidence to the utility of the AUI device for treatment of the AAA, caution must be exhibited in the interpretation of the data. Primarily, the retrospective nature of the trial raises concern for treatment bias. Although the AUI device is an important tool in the treatment of AAA, the applicability to all patients must be done with caution. The number of patients who received the AUI device (389) is a very small sample, relative to those who received the bifurcated stent design (5918). Only 6.2% of all patients analyzed in this review received the AUI design. This finding is important, as we do not know the long-term patency of a femoral artery to a femoral artery bypass graft. By placing the AUI stent, the blood supply to both limbs are at risk if the iliac portion of the device has a mechanical complication. Finally, many of the patients who received the AUI design were patients who were not deemed surgical candidates due to their comorbidities. This same patient population was studied in EVAR II and found to have similar mortality with endovascular repair versus medical therapy. Thus, the increased all-cause mortality in the AUI group may be due to the increased comorbidities of the patient population. We, as an endovascular community, must continue to be critical of our selection criteria for AAA. In conclusion, the article by Riambau and Hobo lends evidence that the AUI device is an important tool for the treatment of AAA, with a similar rate of graft-related complications as the bifurcated design.