The association of transcatheter aortic valve replacement availability and hospital aortic valve replacement volume and mortality in the United States

Background: Whether the introduction of transcatheter aortic valve replacement (TAVR) has affected hospitals' surgical aortic valve replacement (SAVR) and overall aortic valve replacement (AVR) case volumes and outcomes in the United States is unknown.

Methods: We utilized data from The Society of Thoracic Surgeons (STS) adult cardiac surgery database and the STS/American College of Cardiology (ACC) transcatheter valve therapies registry to examine SAVR and TAVR procedures. Temporal trends in total case volume (SAVR plus TAVR), and observed and risk-adjusted in-hospital mortality rates were assessed among low-risk cases (STS predicted risk of operative mortality < 4%), intermediate-risk cases (4% to 8%), and high-risk cases (> 8%). A contemporary control was provided by non-TAVR centers.

Results: From 2008 to 2013, the total annual volume of AVR among 246 TAVR-performing hospitals increased from 19,578 to 33,004, with a 22% growth in SAVR volumes; non-TAVR hospital (n = 555) increases were more modest (16,563 to 19,134; 16% growth). Expanded volumes at TAVR hospitals included increased SAVR use in low- and intermediate-risk cases, and TAVR use in high-risk cases. In parallel, in-hospital mortality for all AVR procedures at TAVR sites declined from 3.4% to 2.9% (observed to expected [O:E] ratio 0.75 to 0.58, p < 0.001); the greatest declines were among intermediate- and high-risk SAVR patients. Owing to reduced SAVR mortality, TAVR centers experienced a significantly greater decline in O:E ratio for high-risk patient in-hospital mortality than non-TAVR centers (TAVR center O:E ratio, 0.81 to 0.61; non-TAVR center O:E ratio, 0.85 to 0.76; p < 0.001). After approval of TAVR for clinical use, a trend toward higher in-hospital mortality rates and O:E ratios for TAVR procedures was observed at new (but not at established) TAVR centers (O:E ratio, 0.41 to 0.67; p = 0.08).

Conclusions: Since the introduction of TAVR, the total volume of AVR procedures, including higher overall use of SAVR, at TAVR sites has significantly increased in the United States. Overall, in-hospital survival of patients undergoing treatment for aortic valve stenosis continues to improve.