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Successful transcatheter aortic valve replacement (TAVR) programs are more likely at higher-quality surgical centers, research suggested.

Using hospital risk-adjusted 30-day mortality for surgical aortic valve replacement (SAVR) in the pre-TAVR period as a proxy for SAVR quality, investigators found slightly higher 30-day TAVR mortality when those programs were established at what had been lower-quality SAVR centers (P<0.001 for trend):

• Quartile 1: 4.6% (reference)

• Quartile 2: 5.0% (adjusted OR 1.02, 95% CI 0.87-1.21)
• Quartile 3: 5.1% (adjusted OR 1.13, 95% CI 1.02-1.26)
• Quartile 4: 5.6% (adjusted OR 1.23, 95% CI 1.07-1.40)

The same pattern was be observed for 1-year TAVR mortality, with a range from 17.0% at the best SAVR centers to 18.6% at the worst, reported Robert Yeh, MD, MSc, of Beth Israel Deaconess Medical Center in Boston, and colleagues online in .

Their study was based on administrative data from Centers for Medicare and Medicaid Services (CMS) spanning the years 2010-2015.

"In this study, we demonstrated that hospitals with higher risk-adjusted mortality after SAVR prior to TAVR approval did indeed have higher short-term and long-term mortality for TAVR during the early phase of TAVR introduction and growth in the United States," the authors said.

"This association between baseline SAVR quality and subsequent TAVR outcomes persisted after adjustment for hospital TAVR volume, which has a powerful association with TAVR outcomes, as well as patient comorbidities and other hospital characteristics."

The role of SAVR quality and the related issue of volumes in TAVR quality has become a hot button issue as a revision of Medicare's requirements for covering TAVR are expected in June 2019.

Another study recently showed that hospitals keeping up both their SAVR and TAVR volumes had the best 30-day survival rates TAVR.

"For the CMS, it is a careful balancing act of quality and access in determining TAVR site and clinician requirements. It is unclear if using the results of this study would reduce the number of sites able to offer TAVR," commented John Carroll, MD, of University of Colorado School of Medicine, Aurora.

Restricting TAVR sites would make it hard for populations with known health care disparities to access this less-invasive procedure. If they do end up at worse TAVR programs, "their outcomes may be adversely affected by social determinants that have nothing to do with the skills and experience of the local heart team," Carroll suggested in an for the study.

Yeh's group highlighted the importance of the heart valve team, noting that surgical teams "remain integral" to TAVR programs, especially since severe complications -- including aortic dissection, left ventricle perforation, and valve embolization or migration -- may require emergency surgery.

The analysis included 519 centers, which together performed more than 50,000 TAVRs during the study period.

In the study, patients undergoing transapical access in particular benefited from going to the highest-quality surgical centers.

That the best SAVR centers produced better TAVR results could be by virtue of better patient selection, better operating theaters, and higher-quality cardiac surgical care units, Yeh and colleagues suggested.

The learning curve should not be forgotten as a factor of valve replacement outcomes, Carroll noted. "This is an important consideration for TAVR, because its dispersion in the United States to hundreds of new and inexperienced sites occurred during the period of data collection used in this study."

A sensitivity analysis excluding hospitals that performed fewer than 10 TAVR procedures did not change the overall findings of the study, although it would have been more rigorous perhaps to exclude up to the first 50 cases from each hospital, the editorialist said.

Yeh's group acknowledged that their reliance on an administrative database left room for residual confounding, inaccuracies due to coding errors, and inadequate risk adjustment due to the lack of important patient characteristics.