Structural Procedural Volumes and In-hospital Transcatheter Aortic Valve Replacement Mortality-Analysis of a National Database

Chatterjee, Saurav

Background:
Importance The Centers for Medicare and Medicaid (CMS) are expected to change national coverage decision (NCD) based on volume of Transcatheter aortic valve replacement (TAVR)–and the CMS NCD has established coronary and TAVR volume thresholds for sites. It remains unknown however if institutional procedural volumes for other structural heart interventions impact in-hospital TAVR mortality to a significant extent. Objective To assess the association between hospital structural procedural volume and in-hospital TAVR mortality.

Methods
Design, Setting, and Participants In this observational study, we used the 2011-2015 Nationwide Re-admissions Database (NRD) to identify all patients undergoing TAVR in the US from years 2011-2015.We also determined in-hospital TAVR mortality by specific volume thresholds of institutional structural procedures. Exposure Volumes of structural procedures including transcatheter mitral interventions (TMVR), Left Atrial Appendage Closure/ Atrial Septal Defect closure/ Patent Foramen Ovale closure (LAAC/ASD/PFO closure) as well as CMS specified threshold of annual institutional TAVR volume. Main Outcomes and Measures In-hospital mortality

Results
Overall annual institutional structural procedural volume of 100 structural procedures was significantly associated with reduced in-hospital TAVR mortality (3.71% for >100 procedures vs 4.2% for <100 procedures, p-value 0.006). Annual TMVR of >= 25 cases was similarly associated with improved TAVR mortality (2.95% for >25 TMVR cases vs 4.08% for <25 TMVR cases, p-value of <0.001). CMS specified annual institutional threshold of >=50 TAVR cases was not associated with lower TAVR mortality, neither was annual LAAC/ASD/PFO closure volume.

Conclusions
An inverse association appears to exist between annual hospital overall structural procedural, as well annual TMVR volumes and in-hospital mortality. Certain other structural procedures may not be associated with improved in-hospital TAVR outcomes. Newer metrics, especially from the structural interventions arena may further define improved TAVR in-hospital mortality outcomes.