NCDR Study Finds Volume-Outcomes Relationship Clinically Important for TAVR

The volume-outcome relationship for transcatheter aortic valve replacement (TAVR) is both statistically significant and clinically important, and TAVR outcomes are shown to improve significantly with increased TAVR volume, according to results of a study presented on April 3 as part of ACC.16 in Chicago.

The trial, conducted by John D. Carroll, MD, FACC, et al., analyzed data from the Society of Thoracic Surgeons (STS)/ACC Transcatheter Valve Therapeutics (TVT) Registry™ to examine the possible relationship between cumulative TAVR volume and in-hospital outcomes in clinical practice in the U.S. All U.S. hospitals submitting consecutive cases to the STS/ACC TVT Registry were evaluated. There were 370 hospitals in the between November 2011 and the third quarter of 2015.

Among 36,292 procedures, the unadjusted in-hospital mortality rate ranged from 0 to 25 percent. Vascular complications, bleeding complications and stroke complication all decreased as TAVR volume increased.

The volume-outcome relationship is intertwined with the learning curve in TAVR. "The early period ('learning curve'), at low site volumes, has the steepest relationship for some outcomes," the authors stated. "The later period, after achieving modest volumes (>100 cases), shows further improvement in outcomes."

The authors stressed that although association does not prove causality, understanding the volume-outcome relationship is important. They write that the data may help inform whether there is an annual volume threshold associated with better outcomes, and posit that it may also aid in patient selection of TAVR centers. Additionally, because the National Coverage Determination from the Centers for Medicaid and Medicare Services considers procedure volume as a future criterion for coverage, the results may help inform decisions regarding optimizing TAVR in the U.S. health care system.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention

Keywords: ACC Annual Scientific Session, Centers for Medicare and Medicaid Services, U.S., Hospital Mortality, Medicaid, Medicare, Morbidity, Transcatheter Aortic Valve Replacement, Registries, STS/ACC TVT Registry, National Cardiovascular Data Registries

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