Retroperitoneal versus Transperitoneal Approach for Open Repair of Complex Abdominal Aortic Aneurysms

Objective: Several studies have demonstrated advantages of the retroperitoneal approach (RP) over the transperitoneal approach (TP) for infrarenal abdominal aortic aneurysm (AAA) repair. A retrospective analysis was performed comparing the outcomes of a TP vs. RP surgical approach for open complex AAA (cAAA) repair and evaluated their relative use over time. Methods: Patients undergoing open repair for intact cAAA (juxtarenal, suprarenal, or type IV thoraco-abdominal aortic aneurysms) between 2011 and 2019 were identified in the National Surgical Quality Improvement Program. The primary outcome was peri-operative death. Secondary outcomes included peri-operative complications and approach use over time. Multivariable adjustment was performed by creating propensity scores and using inverse probability weighted logistic regression. Results: Among 1 195 patients identified, 729 (61%) underwent cAAA repair via a TP approach and 466 (39%) via an RP approach. Compared with a TP approach, RP patients more frequently had a supracoeliac clamp position (32% vs. 20%, p < .001) and concomitant renal revascularisation (30% vs. 18%, p < .001). After adjustment, an RP approach was associated with lower odds of peri-operative death (4.0% vs. 7.2%; odds ratio [OR] 0.54; 95% confidence interval [CI] 0.32 – 0.91; p = .022). Furthermore, an RP approach was associated with lower odds of any major complication (24% vs. 30%; OR 0.73; 95% CI 0.56 – 0.94), cardiac complications (4.9% vs. 8.2%; OR 0.60; 95% CI 0.37 – 0.96), wound complications (2.1% vs. 6.0%; OR 0.34; 95% CI 0.17 – 0.64), and post-operative sepsis (0.8% vs. 2.4%; OR 0.37; 95% CI 0.12 – 0.99). The proportion of repairs using an RP approach decreased between 2011 – 2015 and 2016 – 2019 (42% vs. 35%, p = .020), particularly for suprarenal and type IV thoraco-abdominal aneurysms (49% vs. 37%, p = .023). Conclusion: In open cAAA repair, the RP approach may be associated with lower peri-operative mortality and morbidity rates compared with the TP approach. However, it was found that the relative use of the RP approach is decreasing over time, even in suprarenal/type IV thoraco-abdominal aneurysms, and repairs using a supracoeliac clamp. Increased use of the RP approach, when appropriate, may lead to improved outcomes following open cAAA repair.