The Learning Curve and Annual Procedure Volume Standards for Optimum Outcomes of Transcatheter Aortic Valve Replacement: Findings From an International Registry

ABSTRACT

OBJECTIVES: The authors aimed to determine the procedural learning curve and minimum annual institutional volumes associated with optimum clinical outcomes for transcatheter aortic valve replacement (TAVR).BACKGROUND: Transcatheter aortic valve replacement (TAVR) is a complex procedure requiring significant training and experience for successful outcome. Despite increasing use of TAVR across institutions, limited information is available for its learning curve characteristics and minimum annual volumes required to optimize clinical outcomes. METHODS: The study collected data for patients at 16 centers participating in the international TAVR registry since initiation of the respective TAVR program. All cases were chronologically ordered into initial (1 to 75), early (76 to 150), intermediate (151 to 225), high (226 to 300), and very high (>300) experience operators for TAVR learning curve characterization. In addition, participating institutions were stratified by annual TAVR case volume into low-volume (<50), moderate-volume (50 to 100), and high-volume (>100) groups for comparative analysis. Procedural and 30-day clinical outcomes were collected and multivariate regression analysis performed for 30-day mortality and the early safety endpoint. RESULTS: A total of 3,403 patients comprised the study population. On multivariate analysis, all-cause mortality was significantly higher for initial (odds ratio [OR] 3.83; 95% confidence interval [CI] 1.93 to 7.60), early (OR 2.41; 95%CI 1.51 to 5.03), and intermediate (OR 2.53; 95% CI 1.19 to 5.40) experience groups compared with the very high experience operators. In addition, the early safety endpoint was significantly worse for all experience groups compared with the very high experience operators. Low annual volume (<50) TAVR institutions had significantly higher all-cause30-day mortality (OR 2.70; 95% CI 1.44 to 5.07) and worse early safety endpoint (OR 1.60; 95% CI 1.17 to 2.17) compared with the moderate- and high-volume groups. There was no difference in patient outcomes between intermediate and high annual volume groups. CONCLUSIONS: TAVR procedures display important learning curve characteristics with both greater procedural safety and a lower mortality when performed by experienced operators. In addition, TAVR performed at low annual volume (<50 procedures) institutions is associated with decreased procedural safety and higher patient mortality. These findings have important implications for operator training and patient care at centers performing TAVR.