Increasing surgeon volume correlates with patient survival following open abdominal aortic aneurysm repair

The annual number of open abdominal aortic aneurysm (AAA) repairs has decreased dramatically over the last decade, making the search for physician case volume thresholds more important. The purpose of this study was to identify a minimum threshold for annual surgeon case volume in open AAA repair.

The New York Statewide Planning and Research Cooperative System inpatient database was used to identify all patients undergoing open repair of an intact AAA between 2000 and 2008. Thirty-day survival was calculated using New York State vital records, which contain all New York State death certificates. The annual case volume for each surgeon was defined as the number of open AAA repairs performed in the year of the index procedure. The Contal and O'Quigley method was used to identify a minimum volume threshold.

A total of 11,086 patients were included in the analysis. The selected cutpoint was six or more cases per year based on maximization of the Contal and O'Quigley test statistic. The high-volume group had comparable rates of cardiovascular comorbidities, but significantly improved 30-day and 5-year survival rates as well as shorter lengths of stay in the hospital.

This study identifies an ideal threshold for minimum annual surgeon case volume for open AAA repair. Over the study period, perioperative mortality would not have occurred in up to 150 patients if all procedures had been done by high-volume surgeons performing at least six repairs per year. However, even a minimum annual threshold of at least two repairs per year provided a mortality benefit. Ideal minimum volume thresholds should be developed using rigorous statistical analysis as well as local information about practice patterns.