TAVR Experience vs. Outcomes (STS/ACC TVT Registry)
How does increasing experience after the introduction of transcatheter aortic valve replacement (TAVR) affect clinical outcomes?
The Society of Thoracic Surgeons (STS)/American College of Cardiology (ACC) Transcatheter Valve Therapy (TVT) Registry is a comprehensive national repository of individual patient data from all commercial TAVR cases submitted for reimbursement in the United States. The authors evaluated the association between hospital TAVR volume and patient outcomes after TAVR using data from 42,988 commercial procedures conducted at 395 hospitals submitting to the TVT Registry from 2011 through 2015. Assessed outcomes included adjusted and unadjusted in-hospital major adverse events.
Increasing site volume was associated with lower in-hospital risk-adjusted outcomes including mortality (p < 0.02), vascular complications (p < 0.003), and bleeding (p < 0.001), but not stroke (p = 0.14). From the first case to the 400th in the volume–outcome model, risk-adjusted adverse outcomes declined including mortality (3.57% to 2.15%), bleeding (9.56% to 5.08%), vascular complications (6.11% to 4.20%), and stroke (2.03% to 1.66%). Vascular and bleeding volume–outcome associations were nonlinear, with higher risk of adverse outcomes in the first 100 cases. An association of procedure volume with risk-adjusted outcomes also was seen in the subgroup with transfemoral access.
During the initial adoption of TAVR into practice in the United States, increasing experience was associated with better clinical outcomes. This association, whether deemed a prolonged learning curve or a manifestation of a volume–outcome relationship, suggests that concentrating experience in higher-volume heart valve centers might be a means of improving clinical outcomes.
Greater operator experience and institutional volume have been shown in several areas to be associated with better procedural outcomes. This very large, retrospective, observational study extends those observations to patients undergoing TAVR. After an initial steep learning curve over the course of approximately 100 cases, outcomes continued to improve with higher procedural volumes, reflected by lower rates of major in-hospital adverse events including mortality, bleeding, and vascular complications. Although data in this study cannot be extrapolated to determine whether a significant volume–outcome relationship will persist after operators and sites have achieved progressively more and more experience, there remains an impetus to concentrate procedural experience in discrete heart valve centers.
Keywords: Aortic Valve Stenosis, Cardiac Surgical Procedures, Heart Valve Diseases, Hemorrhage, Outcome Assessment (Health Care), Risk, Stroke, STS/ACC TVT Registry, Transcatheter Aortic Valve Replacement
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