Fenestrated endovascular aneurysm repair (FEVAR) achieves more extensive proximal seal than conventional infrarenal devices, thereby increasing aneurysm exclusion durability. Optimal seal zone length remains undefined. We assessed relative risks and benefits of extending proximal seal above the celiac artery. The prospective database of all complex endovascular aneurysm repairs at a single institution (Institutional Review Board-approved, physician-sponsored investigational device exemption trial, October 2010-June 2017) was used to classify repairs according to number of target visceral-renal arteries incorporated: four vessels vs fewer than four vessels. Comparisons of aneurysm characteristics, perioperative details, and postoperative complications were performed, stratified by repair type. Survival, target artery patency, freedom from type I or type III endoleak, and freedom from reintervention were estimated with Kaplan-Meier analysis. Among 175 FEVARs, 38% (n = 67) were repairs of four vessels and 62% (n = 108) were repairs of fewer than four vessels. Intraoperatively, there was no difference in mean volume of contrast material used (76 mL vs 74 mL; P = NS), but there was increased mean radiation dose (6648 mGy [standard deviation (SD), 2735 mGy] vs 3629 mGy [SD, 2301 mGy]; P < .0001), median procedure time (4.8 hours [interquartile range, 4.1-5.8 hours] vs 3.6 hours [interquartile range, 2.9-4.1 hours]; P < .0001), and mean operating room direct costs ($52,532 [SD, $18,640] vs $40,128 [SD, $15,135]; P < .0001) in four-vessel repairs. There were no differences in mortality (1.9% vs 4.5%), paraparesis (0% vs 3.0%), or paralysis (0.9% vs 0%; all P = NS; Fig). There were no differences in 1-year survival, target artery patency, or freedom from reintervention. There was a lower 1-year freedom from type I or type III endoleak with four-vessel repairs (82% vs 94%; log-rank, P = .02), driven by an increased rate of type III endoleaks. Endoleak resolution after treatment was equivalent in both groups (repair of four vessels, 10/12 [83%] resolved; repair of fewer than four vessels, 7/7 [100%] resolved; P = NS). With FEVAR, use of a supraceliac seal zone compared with an infraceliac seal zone is associated with statistical differences in operative characteristics and resource utilization but negligible clinical significance. Further innovation to eliminate type III endoleaks at fenestrations and branches remains an unmet need. To achieve adequate FEVAR proximal seal zone length, one should have a low threshold to incorporate the celiac artery.