Abstract 314: Institution-level Variability in 30-day Patient Outcomes After Transcatheter Mitral Valve Repair in The United States

Background: Clinical trials have demonstrated that transcatheter mitral valve repair (TMVr) with MitraClip within carefully selected enrolling institutions improves the health status of patients with severe mitral regurgitation. The real-world institution-level variability in health status outcomes for this procedure remain unknown. Methods: Among patients who underwent TMVr at sites participating in the STS/ACC TVT registry from November 2013 to March 2019, health status was measured at baseline and 30 days with the Kansas City Cardiomyopathy Questionnaire-Overall Summary (KCCQ-OS) score. Institution-level variability in 30-day change in KCCQ-OS was examined by calculating the median odds ratio (MOR) from a hierarchical logistic regression model, with ≥20-point improvement as the dependent variable. Results: Our analytic cohort included 12,415 patients (mean age 79.0 ± 9.5 years, 46.1% women, 89.5% White) from 339 sites. Overall mean KCCQ-OS scores were 43.0 ± 24.4 at baseline and 67.0 ± 24.9 at 30 days. There was substantial variability in the percentage of patients at each site, achieving a ≥20-point improvement in KCCQ-OS and in median change in 30-day KCCQ-OS by site; median 22.9, Interquartile Range 36.2 (Figure). The MOR for a ≥20-point improvement in 30-day KCCQ-OS across sites was 1.58 (95% CI 1.46-1.68), which was not reduced after adjusting for baseline health status, comorbidities, procedural complications (residual mitral regurgitation, bleeding) and annual volume of cases per site (fully adjusted MOR 1.58, 95% CI 1.46-1.69). Conclusions: We identified substantial variations in the health status benefits of TMVr across institutions. However, we were unable to identify the causes of this variability, including patient selection (baseline KCCQ-OS and comorbidities), procedural complications, and site volume. Further work is needed to better define how to support more consistent benefits of this novel therapy across institutions.