On May 1, 2012, the Centers for Medicare & Medicaid Services approved a national coverage determination for transcatheter aortic valve replacement (TAVR) procedures. The announcement came six months after the FDA approved the first TAVR valve.
Since then, the technology has improved, as have patient outcomes. The most recent evidence occurred when researchers released results of an observational study that examined 42,988 patients from the Transcatheter Valve Therapy (TVT) registry.
Lead author John D. Carroll, MD, of the University of Colorado Hospital, presented the findings in a late-breaking session at the ACC scientific session on April 3.
The registry, which was created in November 2011 by the American College of Cardiology and Society of Thoracic Surgeons, has information on all patients who have undergone TAVR.
Carroll’s analysis included patients who underwent TAVR from November 2011 through mid-November 2015, spanning first-, second- and third-generation devices. Carroll said that the researchers adjusted for the improvements in TAVR devices, smaller sheath sizes and other factors.
They found that centers that have experienced operators and perform more TAVR procedures have significantly better risk-adjusted in-hospital mortality rates and risk-adjusted bleeding rates compared with less experienced centers. The differences were statistically significant and clinically meaningful, according to Carroll. Over time, centers improve as they do more procedures.
“We base many of our guidelines, many of our current practices, on absolute differences in outcomes of 1 percent,” David Kandzari, MD, of Piedmont Heart Institute in Atlanta, said at a news conference. “When you’re observing mortality differences on the magnitude of 1 to 1.5 percent, these are quite game-changing and quite significant.”
Carroll and Kandzari both noted that the relationship between volume and outcomes was an association and does not indicate a causal relationship. Kandzari also mentioned that the difference between unadjusted outcomes and risk-adjusted outcomes was much higher at low-volume centers compared with high-volume centers.
“It raises the issue, then, are the poorer outcomes in these lower-volume centers a function of simply operator experience or access to methodology or instead is it an issue related to patient selection?,” he said. “Might these lower-volume centers be selecting patients that are at excessive risk that might be better suited at higher-volume institutions? I don’t think the study has the fidelity to provide insight to that, but these are still some of the outstanding questions for us.”