Hospital procedural volume and clinical outcomes for transcatheter aortic valve replacement – US nationwide readmission database, 2016–2019
Authors: Altibi A , Ghanem F , Patel J , Al-Taweel O , Chadderdon S , Song H , Lantz G , Zahr F , Golwala H 
Published: October 2022

Abstract

Background
The number of hospitals offering transcatheter aortic valve replacement (TAVR) programs has increased exponentially in the United States over past several years. Multiple prior studies indicate relationship between hospital volume and clinical outcomes for various cardiac procedures.

Purpose
The association between the hospital procedural volume and clinical outcomes for TAVR is yet poorly understood. In this study, we aim to examine the in-hospital outcomes after TAVR stratified by hospital volume within a nationally representative, large database.

Methods
The National Readmission Database (NRD) 2016–2019 was used to identify hospitals with established TAVR programs (performing ≥20 TAVRs/year). Based on annualized procedural volume of transfemoral TAVR, hospitals were stratified into tertiles of low, medium, and high volume TAVR centers. Rates of adverse in-hospital events (death, cardiac arrest, stroke, vascular complications, and permanent pacemaker), 30-day mortality, and 30-day readmission rates were examined. Multivariate logistic regression analysis was performed to compare overall outcomes following TAVR in low-, medium-, and high-volume centers; adjusted for baseline characteristics and comorbidity burden.

Results
Of 71 million discharge records reviewed, a total of 232,581 patients underwent transfemoral TAVR between 2016–2019. Of all the TAVR cases, 77,183 (33.2%), 75,987 (32.7%), and 79,411 (34.1%) were performed at low-, medium-, and high-volume hospitals respectively. The median number of annual TAVR procedures was 91, 229, and 456 in low-, medium-, and high-volume centers respectively. Adjusted in-hospital mortality was significantly higher in low-volume (OR: 1.40, 95% CI: 1.21–1.62, p&lt;0.01) and medium-volume (OR: 1.29, 95% CI: 1.11–1.50, p&lt;0.01) hospitals compared with high-volume centers. Similarly, adjusted 30-day mortality (OR: 1.45, 95% CI: 1.27–1.66, p&lt;0.01), 30-day readmission rates (OR: 1.11, 95% CI: 1.05–1.18, p&lt;0.01), and in-hospital cardiac arrest (OR: 1.20, 95% CI: 1.08–1.33, p&lt;0.01) were significantly higher for centers in the lowest-volume tertile compared with those in the highest-volume tertile. There were no significant differences in hospital length of stay (mean, 4.3±6.5 days), in-hospital stroke, acute kidney injury, vascular complications, need for permanent pacemaker, or mechanical circulatory support post-TAVR between the three groups.

Conclusion
In the United States, an inverse volume-mortality relationship was observed for transfemoral TAVR procedures from 2016 through 2019. Mortality and readmission rates at 30 days post-TAVR were significantly higher at low-volume hospitals compared with high-volume hospitals. Further research focusing at establishing protocols and standardized training programs may help mitigate the discrepancy in TAVR outcomes amongst hospitals with discrepant procedural volume.

Funding Acknowledgement
Type of funding sources: None.