In the United States, in-hospital outcomes with transcatheter aortic valve replacement (TAVR) have substantially improved as TAVR volume has increased, concluded late-breaking trial data.
“This analysis shows that the volume-outcome relationship is real, is statistically significant [and] clinically meaningful for multiple different outcomes analyzed,” John D. Carroll, MD, study researcher from the University of Colorado, Aurora, Colorado, said during a press conference.
The aim of the study, which was presented at the 2016 American College of Cardiology Scientific Sessions & Expo, was to evaluate the possible association between cumulative TAVR volume and in-hospital outcomes in U.S. clinical practice.
“This has been a very special roll-out in the United States … in that not all sites were able to do TAVR,” Dr Carroll said. “There were prequalifications in terms of site volume and associated procedures, all laid out [and] required for reimbursement. So the national coverage decision really laid out the framework.”
For the study, Dr Carroll and fellow researchers culled data from the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy (TVT) Registry: TAVR Module from November 2011 through the third quarter of 2015.
The transcatheter valves used in the study included only those that had received U.S. Food and Drug Administration approval during the study period.
“The explosion of TAVR has resulted in a lot of patients being treated with these commercially available FDA-approved devices,” Dr Carroll said. “We really wanted to incorporate the latest iteration of the technology, so we had half a year of third-generation devices.”
The final study population included 42 988 patients.
Throughout 400 cases, Dr Carroll and colleagues reported significant improvements in in-hospital mortality (unadjusted P<.0001; risk-adjusted P=.0232). Similarly, researchers also found reductions in bleeding complications, defined as Valve Academic Research Consortium (VARC) major bleeding or VARC life-threatening bleeding, from case 1 to 400 (unadjusted P<.0001; risk-adjusted P<.0001).
“There is an early phase for all sites during their early experience, but then there’s a later period where outcomes continue to improve beyond 100 cases,” Dr Carroll said.
There were several study limitations, he noted, including the observational study design, the complexity of analyzing the volume-outcome relationship, and that the association between outcomes and volume does not prove causality.
Dr Carroll stressed that these data are meant to inform decisions regarding optimizing TAVR in the United States health care system.
“The TVT registry provides results back to institutions—how they do [compared] with national benchmarking,” Dr. Carroll said. “This kind of result is for the country and for all the stakeholders to use in the individual decisions they need to make, [informing] it with solid data.”
- Carroll JD, Vemulapalli S, Dai D, et al. Late-Breaking Clinical Trial III. Relationship between procedure volume and outcome for transcatheter aortic valve replacement in U.S. clinical practice:
- insights from the STS/ACC TVT Registry. Presented at the 65th Annual Scientific Session and Expo of the American College of Cardiology. April 2-4, 2016; Chicago, IL.