The purpose of this study was to determine the effects of patient, surgeon, and hospital factors on survival after repair of ruptured abdominal aortic aneurysm (AAA) and to compare them with risk factors for survival after elective AAA repair. It was hypothesized that patients operated on by high-volume surgeons with subspecialty training would have better outcomes, which might argue for regionalization of AAA surgery.
In this population-based retrospective cohort study, surgeon billing and administrative data were used to identify all patients who had undergone AAA repair between April 1, 1992, and March 31, 2001, in Ontario. Demographic information was collected for each patient, as well as numerous variables related to the surgeons and hospitals. There were 2601 patients with ruptured AAA repair, with an average 30-day mortality rate of 40.8%. Significant independent predictors of lower survival were older age, female gender, lower patient income quintile, performance of surgery at night or on weekends, repair in larger cities, surgeons with lower annual volume of ruptured AAA operations, and surgeons without vascular or cardiothoracic fellowship training. There were 13,701 patients with elective AAA repair, with an average 30-day mortality rate of 4.5%. Significant independent predictors of lower survival were similar, except gender was not significant, but the Charlson Comorbidity Index was. When the hazard ratios associated with predictive factors were compared, surgeon factors appeared to be more important in ruptured AAA repair, and patient factors appeared more important in elective AAA repair.
For elective AAA repair, and even more so for ruptured AAA repair, high-volume surgeons with subspecialty training conferred a significant survival benefit for patients. Although this would seem to argue in favour of regionalization, decisions should await a more complete understanding of the relationship between transfer time, delay in treatment, and outcome.