CHICAGO – An observational study of more than 40,000 transcatheter aortic valve replacement (TAVR) procedures found that outcomes have improved in recent years as hospitals and physicians perform more procedures.

Lead author John D. Carroll, MD, of the University of Colorado Hospital, presented the results in a late-breaking session at the ACC scientific session on April 3.

The researchers evaluated 42,988 patients from the Transcatheter Valve Therapy (TVT) registry, which was created by the ACC and Society of Thoracic Surgeons when the FDA approved the first TAVR device in November 2011. At the time, the Centers for Medicare & Medicaid Service released a national coverage determination that mandated hospitals meet certain qualifications to receive reimbursement for TAVR procedures.

“It’s important to know how therapies are distributed and what the outcomes are in real practice, not in clinical trials only in highly select groups, high volume operators, et cetera,” Carroll said in a news conference. “We need to see it in real-world therapy. That’s why the TVT registry was organized as a learning process for sites, for patients, for regulatory agencies, for the country as a whole.”

Of the 395 sites evaluated in this study, hospitals performed a mean of 108.8 and a median of 80 TAVR procedures between November 2011 and the third quarter of 2015. Meanwhile, the median risk-adjusted mortality rate was 4.03 percent.

Carroll said that sites that performed a high volume of TAVR procedures had statistically significant, clinically meaningful reductions in risk-adjusted in-hospital mortality. There were similar reductions in risk-adjusted bleeding.

“In the context of TAVR, outcomes are improving,” Carroll said. “We know there are a lot of different factors that go into that. The one that needed to be studied was volume. This analysis shows that that volume-outcome relationship is real, is statistically significant and clinically meaningful for multiple different outcomes analyzed.”

Carroll said the relationship between volume and outcomes was an association and not a causal relationship. However, he noted the association between the volume of TAVR procedures performed and outcomes was statistically significant and held after adjusting for patient characteristics and time.

“These results, these data, are to inform decisions regarding optimimizing TAVR in the U.S. healthcare system,” Carroll said. “The TVT registry provides results back to institutions, how they do with national benchmarking. This kind of result is for the country and for all the stakeholders to use this in their individual decisions that they need to make, but it informs it with solid data.”