Higher-Volume TAVR Centers Show Lower Mortality

Debra L. Beck

April 04, 2019

UPDATED April 8, 2019 // Thirty-day mortality was lowest at hospitals that perform the highest volume of transfemoral transcatheter aortic valve replacement procedures and, conversely, trended higher and was more variable at hospitals with lower procedural volumes, new registry data show.

The findings, published online April 3 in the New England Journal of Medicine, come just 1 week after the US Centers for Medicare and Medicaid Services (CMS) released a proposed update to their transcatheter aortic valve replacement (TAVR) reimbursement criteria that make hospital procedural volumes a key criterion for reimbursement.

"We looked mainly at hospital-level performance because that's what CMS is most interested in, but I think it's also very relevant because, unlike most interventional cardiology procedures, TAVR really is a team procedure, so the impact of individual operators is blunted by this team approach," said Sreekanth Vemulapalli, MD, Duke University Medical Center, Durham, North Carolina.

He noted in an interview that they also looked at the relationship between individual operator volume and 30-day mortality and found a similar pattern.

The analysis is the largest of its kind to date and used data from the Transcatheter Valve Therapy (TVT) Registry from 2015 to 2017.

Of 113,662 TAVR procedures performed at 555 hospitals by 960 operators, 96,256 (84.7%) involved a transfemoral approach.

Adjusted 30-day mortality was 3.19% in the lowest volume quartile, compared with 2.66% in the highest-volume quartile (odds ratio, 1.21; P = .02). Put another way, the difference in adjusted mortality between a mean annualized volume of 27 procedures and 143 procedures was a relative reduction of 19.45%.

"We didn't identify a magic number above which there is no longer a relationship between volume and outcome, but it looks, from our data, that after about 50 TAVRs per operator and 100 per hospital, the outcomes don't really get a whole lot better," Vemulapalli told theheart.org | Medscape Cardiology.

To avoid any criticism that their numbers might reflect the learning curve, the researchers conducted a sensitivity analysis that excluded data from the first 6 months of TAVR performance at each hospital (if that first 6 months fell in the study period). The outcomes were almost exactly the same as in the main analysis.

This new analysis reflects the most recent data available and comes years after TAVR was first introduced commercially in the United States, in 2011, emphasizing the persistence of the volume–mortality relationship.

"I think the debate is about how to balance quality and access to care," said Vemulapalli.

"If we're really trying to use volume as a measure of quality, then these data should help to inform CMS on how to do that, but the flip side of the conversation is that if we, say, make a cutoff where all hospitals doing fewer than 100 TAVR procedures a year have to stop, then there will likely be individuals who won't be able to have the procedure, although this has not been proven."

"The more you do something, the better you get at," is an idea that seems to apply only up to a certain point, cardiothoracic surgeon Michael J. Reardon, MD, Houston Methodist Hospital, told theheart.org | Medscape Cardiology.

"It's not completely the 'Malcolm Gladwell 10,000 hours of practice makes perfect' idea because that really only applies to things to which the rules never change, like chess or violin playing, and medicine changes constantly. But I agree with their conclusions that there is an operator and institutional experience relationship to outcomes."

Still, he questioned how much importance the study seems to place on institutional case volume. "If you have an institution with six TAVR teams and they're doing 200 cases a year, there might be a team doing 75 cases, a couple doing just 10, and maybe one team doing three cases a year — and that last team is playing into the institution's outcomes too."

Reardon also proposed that there is a "political" component at play, in that surgeons aren't held to the same account. "I can do one aortic valve replacement a year and I will still be fully credentialed by my hospital."

Indeed, for most types of procedures, TAVR being an exception, he explained, volume requirements are set at a local institutional level. But, partly because of pushback from different subspecialties on who should be doing carotid stenting, and then TAVR, they arrived on the scene, a national coverage position for TAVR was established and that dynamic persists.

"I think at some point we'll move on from volume to quality and get back to 'all politics is local' and solve it locally," said Reardon.

This story was updated to add comments from Reardon.

Funding for the study was provided by the Society for Thoracic Surgeons and the American College of Cardiology through the National Cardiovascular Data Registry. Vemulapalli reported no conflicts of interest.

N Engl J Med. Published online April 3, 2019. Abstract

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