As CMS finalizes minimum requirements, study affirms value of volume
Case volumes still matter in transcatheter aortic valve replacement (TAVR) outcomes, despite recent advances in technology and patient selection, a registry study showed.
Among centers participating in the Transcatheter Valve Therapy (TVT) Registry from 2015 to 2017, hospitals performing the most transfemoral TAVRs per year had 19.45% lower adjusted risk of 30-day patient mortality than those performing the fewest TAVRs (mean annualized volume 143 vs 27 procedures per year).
Analyzing hospital volume by quartiles produced similar results, as risk-adjusted mortality was 3.19% in the lowest volume quartile doing 36 or fewer per year and 2.66% in the highest quartile doing at least 86 per year (adjusted OR 1.21, 95% CI 1.03-1.41).
These findings reported by Sreekanth Vemulapalli, MD, of Duke University Medical Center in Durham, North Carolina, and colleagues in the New England Journal of Medicine updated similar results from the TVT Registry presented to a Centers for Medicare and Medicaid Services (CMS) advisory panel in mid-2018. In March, the agency proposed to ease but not eliminate these requirements.
"These results are from current practice in the United States and illustrate the major improvement in 30-day mortality with TAVR, from 7.5% in 2012 to a modeled rate that now approaches 2.5 to 3.0% in transfemoral TAVR," the investigators wrote.
However, that volume-mortality association persists "despite improved patient selection, technology, and techniques as well as expansion of indications to intermediate-risk patients," they added, noting that lower-volume hospitals also had greater variability in mortality.
"In general, I think these findings support the newly-proposed TAVR requirements from CMS, which impose strict volume thresholds," commented Robert Yeh, MD, of Beth Israel Deaconess Medical Center in Boston.
"The CMS requirements go a bit farther than this though, including requiring maintenance of surgical AVR volume, which is supported by previous literature showing a relationship between surgical AVR outcomes and subsequent TAVR quality," he added.
Vemulapalli and colleagues analyzed 113,662 TAVR cases listed in the TVT Registry, of which 84.7% were performed through a transfemoral approach. In total, there were 555 hospitals and 2,960 operators involved.
The volume-outcomes relationship appeared to hold strong even after a center should have passed the learning curve for TAVR: A sensitivity analysis excluding the first 12 months of transfemoral TAVR at each hospital still showed greater odds of adjusted 30-day mortality among lowest-volume compared to highest-volume centers (3.10% vs 2.6%, adjusted OR 1.19, 95% CI 1.01-1.40).
Centers with lower procedural volumes were more likely to be rural, and they performed relatively more TAVRs on racial and ethnic minorities, the researchers noted.
TAVR's accessibility in the U.S. was one of the key considerations discussed by the CMS advisory panel considering its TAVR National Coverage Determination (NCD), which stipulates institutional and operator volume requirements for reimbursement.
"The question becomes whether the imposition of these volume thresholds by CMS will reduce access of this life-saving technology to historically disadvantaged populations and increase healthcare disparities. Making sure that we enable these populations to be able to receive TAVR will be an important priority as new regulations go into effect," Yeh told MedPage Today.
Vemulapalli's group cautioned against linking reimbursement to direct quality metrics without an external certification or accreditation system. "In addition, we think an updated NCD should include an effective mechanism to require hospitals to submit complete and accurate data for quality metrics to be valid," the investigators said.
They acknowledged that their retrospective observational study had potential for residual confounding. Furthermore, the TVT Registry only captured TAVR cases performed commercially and did not count those included in clinical trials.
The study was supported by the American College of Cardiology Foundation National Cardiovascular Data Registry and the Society of Thoracic Surgeons.
Vemulapalli disclosed contract work with the Society of Thoracic Surgeons and the American College of Cardiology; and receiving grants and/or personal fees from Boston Scientific, Abbott Vascular, the Patient Centered Outcomes Research Institute, the Agency for Healthcare Research and Quality, Premiere, Janssen, Novella, and Zafgen.
New England Journal of Medicine
Source Reference: Vemulapalli S, et al "Procedural volume and outcomes for transcatheter aortic-valve replacement" New Engl J Med 2019; DOI: 10.1056/NEJMsa1901109.
Read the original article on Medpage Today: TAVR Volume-Mortality Relationship Holds Strong