- The concentration of transcatheter aortic valve replacement sites in certain urban areas may be reducing case volumes, thereby slowing learning and leading to worse health outcomes after the heart procedure.
- That proposition, which is set out in the Journal of the American College of Cardiology, is based on an analysis of the growth in TAVR sites from 2011 to 2018. The study linked higher site density and lower annual volumes to an increased risk of mortality.
- In an accompanying editorial, two Mayo Clinic cardiologists used the findings to call for CMS to withhold reimbursement from sites that fail to meet its original selection or quality criteria.
The question of which sites should get to perform TAVR has remained a live issue throughout the 10 years the procedure has been performed in the U.S. In light of the expertise needed to use the early TAVR devices, as well as the high risks of working with the original patient population, cardiology and surgical societies worked with other groups to limit the procedure to qualified sites.
CMS reconsidered its position in 2019 but, despite lobbying by some groups, the agency tweaked rather than overhauled its approach. A subsequent analysis found rural hospitals are less likely to be eligible to offer TAVR under the new policy.
Now, an evaluation of the Transcatheter Valvular Therapy registry data gathered from 2011 to 2018 has identified a potential flaw with the concentration of TAVR sites in urban areas.
Over that period, the number of TAVR sites in the TVT registry grew from 198 to 556. The growth brought the median drive-time from existing to new sites down from 403 minutes to 26 minutes, pointing to the concentration of centers in certain areas.
Large metropolitan areas have access to more patients and can therefore support more TAVR sites, but at some point the addition of new centers will cause the number of cases handled at individual locations to fall. The study found evidence that increased site density and lower case volumes are having negative effects, potentially because they prevent the concentration of experts at single sites.
"TAVR has expanded significantly over time, but with regional clustering of sites," the authors wrote. "Although procedural risk is lower at higher density sites, these sites demonstrate an increased hazard of mortality. These findings suggest that the expansion of TAVR services in the United States may have had unintended consequences on procedural quality."
Mayo Clinic's David R. Holmes and D. Craig Miller dug into the unintended consequences and what to do about them in an accompanying editorial. The cardiologists said low-volume or inexperienced centers may accept high-risk patients rejected for TAVR by other sites to boost their volumes, leading to negative outcomes.
The authors also contend that the proliferation of sites in urban regions that already have at least one TAVR program has left rural regions of the country unrepresented, potentially contributing to "worsening disparities of care."
Faced with the situation, Holmes and Miller argued that "appropriate site and operator qualifications should be identified up front and adhered to throughout the device life cycle" and called for changes to ensure "reasonable geographic dispersion" of TAVR sites by tying reimbursement to the process.
"If sites in the United States do not meet the selection criteria for site selection originally formulated or do not meet the 1-year TAVR quality outcome benchmarks, CMS withholding future reimbursement or considering reimbursement 'penalties' should be strongly considered," the cardiologists wrote.