Influence of surgical volume on outcomes in low-risk patients undergoing isolated surgical aortic valve replacement

Intermediate- and high-risk patients undergoing isolated surgical aortic valve replacement have superior outcomes at higher-volume compared with lower-volume hospitals. This study examines the impact of hospital volume on outcomes in low-risk patients undergoing aortic valve replacement.

Using data from our 29 North Texas hospital collaborative, we examined 2066 low-risk cases (Society of Thoracic Surgeons Predicted Risk of Mortality of ≤3%) undergoing aortic valve replacement surgery between January 1, 2012, and December 31, 2017. Cases from 3 high-volume hospitals (≥200 aortic valve replacement cases total) and 26 low-volume hospitals (<200 cases total) were examined.

Some 53.5% of the cases were at high-volume hospitals. No statistical differences were seen in the Predicted Risk of Mortality or pertinent demographics between the high-volume and low-volume hospitals. Significant differences in outcomes were seen between the 2 groups in operative mortality (2.28% vs 1.19%, P = .007), renal failure (2.14% vs 1.00%, P = .003), and readmission within 30 days (9.72% vs 6.25%, P < .001) when comparing low-volume with high-volume hospitals. In patients undergoing aortic valve replacement, undergoing the procedure in a low-volume hospital was an independent predictor for operative mortality (odds ratio, 1.95; 95% confidence interval, 1.20-3.20; P = .008) and renal failure (odds ratio, 2.25; 95% confidence interval, 1.33-3.81; P = .003).

Operative mortality in low-risk patients undergoing aortic valve replacement is higher in low-volume compared with high-volume hospitals. The probability of a major complication, such as renal failure, is also greater in low-volume hospitals. The relationship between volume and outcomes in low-risk patients will require more research to understand the causes and design appropriate interventions.