BACKGROUND: The approach for open infrarenal Abdominal Aortic Aneurysm (AAA) repair is mainly surgeon driven based on experience and prior training. While the midline Transperitoneal (TP) remain the most common, the Retroperitoneal (RP) approach is usually utilized in more complex cases where suprarenal cross-clamping is necessary. As prior literature is conflicting on optimal outcomes between the two approaches, we aimed to compare RP vs TP outcomes stratified by aortic clamp level. STUDY DESIGN: The Vascular Quality Initiative database was queried for all patients who underwent open AAA repair from January 2012 to February 2024. Patients were stratified according to aortic cross-clamp site: infrarenal, interrenal, suprarenal, and supraceliac. We used multivariate logistic regression to analyze outcomes of RP vs TP within each clamp site while adjusting for baseline and clinically relevant variables. RESULTS: A total of 8,842 patients were included. Compared to TP, RP approach was associated with higher odds of postoperative dialysis [aOR=1.74,(95%CI 1.07-2.83),p=0.025) with infrarenal cross-clamping. However, at higher clamping sites RP was associated with lower odds of bowel ischemia [aOR=0.40,(95%CI 0.20-0.80),p=0.009] with interrenal clamping
lower odds of dialysis [aOR=0.66,(95%CI 0.44-0.99),p=0.048], bowel ischemia [aOR=0.52,(95%CI 0.32-0.85),p=0.009) and 30-day mortality [aOR=0.48,(95%CI 0.30-0.79),p=0.004) with suprarenal clamping
and lower in-hospital [aOR=0.35,(95%CI 0.16-0.80),p=0.013) and 30-day mortality [aOR=0.41,(95%CI 0.17-0.98),p=0.046] with supraceliac clamping. CONCLUSION: In this large multi-institutional study, we identified that differential outcomes of RP vs TP approaches for open AAA are modified by aortic cross-clamping level. RP is associated with lower postoperative complications and better survival compared to TP in cases requiring more proximal cross-clamping sites. However, TP approach is associated with lower risk of renal complications in cases restricted to infrarenal clamping.