Influence of Surgeon Volume on Outcomes With Aortic Valve Replacement

Abstract

A volume-outcome association has been shown for cardiovascular procedures such as coronary artery bypass grafting. The association of a volume-outcome relationship for aortic valve replacement procedures, however, has not been clearly defined. We evaluated the influence of surgeon volume on operative outcomes with isolated aortic valve replacement and aortic valve replacement with concomitant coronary artery bypass grafting. One thousand six hundred thirty-five patients were identified as having either isolated aortic valve replacement or aortic valve replacement plus coronary artery bypass grafting between January 1, 2000, and December 31, 2009. Patients were divided into three equal terciles using their Society of Thoracic Surgery Predicted Risk of Mortality scores. Data were retrieved on 14 surgeons with complete data records in our Society of Thoracic Surgery database covering a minimum 5-year period (mean, 8.9 ± 1.5 years; median, 10 years). Clinically significant increases are seen in operative mortality, permanent stroke, renal failure, prolonged ventilation, and hospital and intensive care unit lengths of stay in the high-risk compared with low-risk groups. The low-risk patient group has the smallest observed to expected ratio, less than 50%, whereas in the high-risk group the ratio is greater than 1. Odds ratios demonstrate that as surgeon volume increases, outcomes improve correspondingly (ie, odds ratio <1). In low-risk patients, five of ten major complications demonstrated improved outcomes with increased surgeon volume; in medium and high-risk groups eight of ten were improved. Surgeon volumes have a significant influence on operative outcomes in high-risk patients undergoing aortic valve replacement or aortic valve replacement with coronary artery bypass grafting.