(IPC23) Proficiency in Retroperitoneal Exposure Predicts Superior Outcomes in Open Abdominal Aortic Aneurysm Repair

Objectives: Open abdominal aortic aneurysm repair (OAAA) can be performed using transperitoneal (TP) or retroperitoneal (RP) approaches. With the increased shift towards endovascular repair, trainees are encountering fewer open aortic cases. Although historically TP is more common, RP enables improved exposure of the perivisceral aorta. Since most OAAAs require more proximal clamping, experience with RP is valuable. We hypothesize that proficiency in both exposures may contribute to improved surgical outcomes.

Methods: The Vascular Quality Initiative was queried from January 2003 to August 2024 for patients who underwent OAAA repair through TP or RP approach. Each surgeon in the database is deidentified and given a unique ID indicating operations they perform. We had two main groups in our study: 1-TP only: OAAA performed by surgeons who utilized the TP approach only 2-Both: OAAA performed by surgeons who did both RP and TP approaches. We excluded ruptures and surgeons with less than two operations recorded in the registry. Propensity score matching (1:1) was used to match baseline characteristics of patients in both groups. Matched covariates (27 variables) include demographics, comorbidities, cross-clamp level, aneurysm size, and medications. Logistic regression after matching analyzed primary (30-day mortality) and secondary outcomes (postoperative stroke, myocardial infarction, renal failure requiring dialysis, bowel ischemia, respiratory complications, and prolonged hospitalization).

Results: A total of 13,543 open AAA repairs were included [TP only 2,892 (21.4); both approaches 10,651 (78.6%)]. Patients operated on by the both approaches surgeons were more likely to be older, female, hypertensive, and with history of CAD. After matching, two well balanced cohorts of 2,853 patients in each group were produced (SD < 0.1). Compared to surgeons who do both approaches, OAAA performed by the TP only surgeons were associated with 61% increased odds of 30-day mortality [OR=1.61(1.19-2.16),p=0.002)], 53% higher risk of in-hospital death [OR=1.53(1.14-2.07),p=0.005)], and 44% higher odds of postoperative dialysis [OR=1.44(1.06-1.97),p=0.020)](Table I). A subsequent sub-analysis showed that TP only surgeons had double the odds of 30-day mortality in cases requiring infrarenal clamping [OR=1.99(1.31-3.02),p=0.001)](Table II). Furthermore, surgeons who utilize both approaches still had better 30-day survival even if the case was done through TP approach [OR=1.69,(1.20-2.37),p=0.002].

Conclusions: The results of our study highlight the value of comprehensive training in both RP and TP exposure techniques in OAAA repair. Mastering RP exposure may serve as a marker of surgical proficiency, reflecting the breadth of a surgeon’s skillset. Vascular surgery residents and fellows should be trained to be comfortable performing both approaches.