Prophylactic sac outflow vessel embolization is associated with improved sac regression in patients undergoing endovascular aortic aneurysm repair

Objective: Type II endoleaks (T2Es), often identified after endovascular aneurysm repair (EVAR), have been associated with late endograft failure and secondary rupture. The number and size of the patent aortic aneurysm sac outflow vessels (ie, the inferior mesenteric, lumbar, and accessory renal arteries) have been implicated as known risk factors for persistent T2Es. Given the technical challenges associated with post-EVAR embolization, prophylactic embolization of aortic aneurysm sac outflow vessels has been advocated to prevent T2Es; however, the evidence available at present is limited. We sought to examine the effects of concomitant prophylactic aortic aneurysm sac outflow vessel embolization in patients undergoing EVAR. Methods: Patients aged >= 18 years included in the Society for Vascular Surgery Vascular Quality Initiative database who had undergone elective EVAR for intact aneurysms between January 2009 and November 2020 were included in the present study. Patients with a history of prior aortic repair and those without available follow-up data were excluded. The patient demographics, operative characteristics, and outcomes were analyzed by group: EVAR alone vs EVAR with prophylactic sac outflow vessel embolization (emboEVAR). The outcomes of interest were the in-hospital postoperative complication rates, incidence of aneurysmal sac regression (>= 5 mm) and T2Es, and reintervention rates during follow-up. Results: A total of 15,060 patients were included. Of these patients, 272 had undergone emboEVAR and 14,788 had undergone EVAR alone. No significant differences were found between the two groups in age, comorbidities, or anatomic characteristics, including the mean maximum preoperative aortic diameter (5.5 vs 5.6 cm; P = .48). emboEVAR was associated with significantly longer procedural times (148 vs 124 minutes; P< .0001), prolonged fluoroscopy times (32 vs 23 minutes; P < .0001), increased contrast use (105 vs 91 mL; P < .0001), without a significant reduction in T2Es at case completion (17.7% vs 16.3%; P = .54). The incidence of postoperative complications (3.7% vs 4.6%; P = .56), index hospitalization reintervention rates (0.7% vs 1.3%; P = .59), length of stay (1.8 vs 2 days; P = .75), and 30-day mortality (0% vs 0%; P = 1.00) were similar between the two groups. At mid-term follow-up (14.6 +/- 6.2 months), the emboEVAR group had a significantly greater mean reduction in the maximum aortic diameter (0.69 vs 0.54 cm; P = .006), with a greater pro portion experiencing sac regression of >= 5 mm (53.5% vs 48.7%). The reintervention rates were similar between the two groups. On multivariable analysis, prophylactic aortic aneurysm sac outflow vessel embolization (odds ratio, 1.34; 95% confidence interval, 1.04-1.74; P = .024) was a significant independent predictor of sac regression. Conclusions: Prophylactic sac outflow vessel embolization can be performed safely for patients with intact aortic aneurysms undergoing elective EVAR without significant associated perioperative morbidity or mortality. emboEVAR was associated with significant sac regression compared with EVAR alone at mid-term follow-up. Although no decrease was found in the incidence of T2Es, this technique shows promise, and future efforts should focus on identifying a subset of aneurysm and outflow branch characteristics that will benefit from concomitant selective vs complete prophylactic sac outflow vessel embolization.