Effect of institutional transcatheter aortic valve replacement volume on mortality: A systematic review and meta-analysis

Objective: We sought to conduct a systematic review and network meta-analysis to examine the association between institutional transcatheter aortic valve replacement (TAVR) volume and all-cause mortality. Background: Since inception in 2011, there has been an exponential increase in the number of TAVR centers across the world. Multiple studies have questioned if a relationship exists between institutional TAVR volume and patient outcomes. Methods: We performed a systematic literature search for relevant articles using a combination of free text terms in the title/abstract related to volume, TAVR, and patient outcomes. Two reviewers independently screened all titles/abstracts for eligibility based on pre-specified criteria. All-cause mortality data was pooled from eligible studies and centers were categorized as low-(30–50 cases), intermediate-, or high-volume (75–130 cases) based on their annual TAVR volumes. Results: Our search yielded an initial list of 11,153 citations, 120 full text studies were reviewed and 7 studies met all inclusion and exclusion criteria, yielding a total of 1,93,498 TAVRs. Categorized according to center's annual volume; 25,062 TAVRs were performed in low-, 77,093 in intermediate- and 91,343 in high-volume centers. Network meta-analysis showed a relative reduction in mortality rates of 37%, 23% and 19%, for high volume versus low volume centers, high volume versus intermediate volume centers and intermediate versus low volume centers, respectively. Conclusions: Existing research clearly shows an inverse relationship between annual TAVR procedural volume and all-cause mortality. We need to focus on development of strong referral networks and consolidation rather than expansion of existing TAVR centers to improve patient outcomes, while ensuring adequate access-to-care.