Long-term survival and temporal trends in patient and surgeon factors after elective and ruptured abdominal aortic aneurysm surgery

Abstract

Objective: Records for all patients in Ontario who underwent elective repair of abdominal aortic aneurysms (AAAs) or repair of ruptured AAAs between 1993 and 1999 were studied to determine whether the profile of surgeons or patients changed and to determine whether postoperative mortality changed over time. The secondary objective was to describe long-term survival after AAA surgery.

Methods: A population-based retrospective cohort was assembled from administrative data. Surgeon billing records were used to identify operations performed between 1993 and 1999. Chi(2) and linear regression analyses were used to determine whether variables changed over time. Kaplan-Meier survival curves were used to estimate long-term survival.

Results: For patients undergoing elective AAA repair, average annual surgeon volume (P <.0001) and proportion of patients operated on by vascular surgeons (P =.02) increased over the study period; similar trends were noted for patients undergoing repair of ruptured AAAs. Surgeon volume was clearly correlated with mortality after both elective AAA repair and repair of ruptured AAAs; however, the benefit of this effect was modest beyond a surgeon volume of 6 to 10 ruptured AAA repairs per year or 20 to 30 elective AAA repairs per year. No change in crude 30-day mortality (4.5% for elective AAA repair and 40.4% for repair of ruptured AAAs) was noted during the study.

Conclusion: Despite the finding that surgery to repair ruptured AAAs and elective repair of AAAs is being increasingly performed by high-volume vascular surgeons, there was no change in early mortality between 1993 and 1999. This may have been because average surgeon volume was already relatively high at the beginning of the study period, which translated into only modest benefit to further increases in surgeon volume.