Relation of Hospital Volume With In-Hospital and 90-Day Outcomes After Transcatheter Mitral Valve Repair Using MitraClip

MitraClip therapy has shown increasing use since it was commercially adopted among US hospitals in October 2013. However, the relation of institutional MitraClip volume with outcomes is unclear. This study sought to examine the association between hospital volume and outcomes after transcatheter mitral valve repair using the MitraClip device. Using the Nationwide Readmissions Database, we identified all patients who underwent a MitraClip procedure and categorized hospitals into tertiles based on their annual procedure volume: low (≤3 procedures/year), medium (4 to 13/year), and high (≥14/year)volume centers. Multivariable logistic and Cox regression analyses were performed to examine the impact of institutional MitraClip volume on in-hospital and 90-day outcomes, respectively. From 2014 to 2015, a total of 3,420 procedures were performed at 266 hospitals with a median annual procedural volume of 5 per hospital. Low (n = 81), medium (n = 86), and high (n = 99)volume hospitals performed 147 (4.3%), 403 (11.8%), and 2,870 (83.9%)MitraClip procedures, respectively. The low versus high hospital volume was independently associated with increased in-hospital mortality (7.8% vs 3.0%; adjusted odds ratio [aOR]2.64; p = 0.04), acute myocardial infarction (10.2% vs 2.2%; aOR 2.93; p = 0.02), and acute respiratory failure (19.3% vs 7.7%; aOR 2.24; p = 0.02)during index admission as well as 90-day all-cause readmissions (37.8% vs 26.6%; adjusted hazard ratio 1.54; p = 0.03), and 90-day infective endocarditis (2.4% vs 0.3%; adjusted hazard ratio 10.06; p = 0.003). In conclusion, low hospital MitraClip volume is an independent determinant of worse outcomes including in-hospital mortality and 90-day readmissions.