(IP019) Comparative Analysis of Outcomes for Retroperitoneal versus Transperitoneal Approaches in Open Repair of Stable Ruptured Abdominal Aortic Aneurysms

Objectives: Retroperitoneal (RP) approach has been associated with lower peri-operative mortality and morbidity rates compared to the transperitoneal approach (TP) for elective abdominal aortic aneurysm (AAA) repair. However, it is unclear if there is a benefit of RP approach in patients undergoing open repair for stable abdominal aortic aneurysm (AAA) ruptures. We utilized the National Surgical Quality Improvement Program (NSQIP) to better understand these outcomes.

Methods: All patients who underwent open repair of stable ruptured AAA, as recorded in the NSQIP between 2011 and 2022, were included. The primary outcome of interest was perioperative mortality. Secondary outcomes encompassed a range of perioperative outcomes, including mortality, cardiac, and respiratory complications. To address potential confounding, inverse probability of treatment weighting (IPTW) was first applied to account for demographic factors, comorbidities, and procedural characteristics. After weighting, a logistic regression analysis was employed.

Results: A total of 331 patients (22% RP) underwent open repair of ruptured AAA without hypotension. Compared to the TP cohort, patients in the RP cohort were more likely to have undergone previous abdominal aortic surgery (39% vs. 21%, p=0.002). No significant differences were observed between approaches in terms demographics or comorbidities. Patients undergoing RP approach were more likely to be performed for aneurysm involving or extending proximal to the renal arteries (52% vs 39%, p=0.005) and utilize a suprarenal clamp site (63% vs 47% infrarenal, p=0.01), but were similar regarding large AAA diameter, distal aneurysm extent, concomitant procedures, and operative time (Table 1). Patients who underwent the RP approach exhibited lower odds of perioperative mortality (13% vs. 27%; adjusted odds ratio [aOR], 0.41; 95% confidence interval [CI], 0.23–0.69; p=0.001), cardiac complications (7.5% vs. 15%; aOR, 0.45; [95% CI, 0.22–0.87]; p=0.02), and respiratory complications (8.9% vs. 16%; aOR, 0.52; [95% CI, 0.26–0.98]; p=0.049). Odds of ischemic colitis (4.6% vs 3.3%) and major renal complications (14% vs 19%) were similar between the RP and TP approaches (Table 2).

Conclusions: Our analysis suggests potential benefits of the RP approach in patients who present with a stable ruptured aneurysm. The RP cohort demonstrated significantly reduced perioperative mortality, as well as lower incidences of both cardiac and respiratory complications. These results underscore the potential value of employing an RP technique for stable patients undergoing open repair of ruptured AAA to enhance perioperative safety and improve survival outcomes.