Procedural Volume and Outcomes for TAVR

Study Questions:

What is the association between hospital or operator volume of transcatheter aortic valve replacement (TAVR) procedures and 30-day unadjusted and risk-adjusted outcomes?

Methods:

The investigators analyzed data from the Society of Thoracic Surgeons–American College of Cardiology Transcatheter Valve Therapy Registry regarding procedural volumes and outcomes from 2015 through 2017. The primary analyses examined the association between hospital procedural volume as a continuous variable and risk-adjusted mortality at 30 days after transfemoral TAVR. Secondary analysis included risk-adjusted mortality according to quartile of hospital procedural volume. A sensitivity analysis was performed after exclusion of the first 12 months of transfemoral TAVR procedures at each hospital. The primary prespecified analysis examined the association between hospital procedural volume as a continuous variable and risk-adjusted 30-day mortality. Generalized linear mixed models were developed to assess hospital TAVR volume–outcome relationships.

Results:

Of 113,662 TAVR procedures performed at 555 hospitals by 2,960 operators, 96,256 (84.7%) involved a transfemoral approach. There was a significant inverse association between annualized volume of transfemoral TAVR procedures and mortality. Adjusted 30-day mortality was higher and more variable at hospitals in the lowest-volume quartile (3.19%; 95% confidence interval [CI], 2.78-3.67) than at hospitals in the highest-volume quartile (2.66%; 95% CI, 2.48-2.85; odds ratio, 1.21; p = 0.02). The difference in adjusted mortality between a mean annualized volume of 27 procedures in the lowest-volume quartile and 143 procedures in the highest-volume quartile was a relative reduction of 19.45% (95% CI, 8.63-30.26). After the exclusion of the first 12 months of TAVR procedures at each hospital, 30-day mortality remained higher in the lowest-volume quartile than in the highest-volume quartile (3.10% vs. 2.61%; odds ratio, 1.19; 95% CI, 1.01-1.40).

Conclusions:

The authors concluded that an inverse volume–mortality association was observed for transfemoral TAVR procedures from 2015 through 2017.

Perspective:

This registry study reports that higher hospital and operator TAVR procedural volumes were associated with significantly lower 30-day mortality. Furthermore, the inverse relationship persisted after the exclusion of patients from the 6- and 12-month start-up period at each hospital. It should be noted that this is a retrospective observational study and is therefore subject to residual confounding and the study also included data only on commercially performed TAVR cases. Of note, another analysis published this year from the same TVT registry (Russo MJ, et al., J Am Coll Cardiol 2019;73:427-40) suggested that after a modest initial experience of about 200 TAVR procedures with the balloon-expandable prosthesis, the learning curve flattens and there is then little relationship between case volume and clinical outcomes. As the procedural indications for TAVR expand, and with refinements of procedural techniques and advances in device technology, additional prospective data to assess true volume–outcome relationships will be needed.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Prevention, Valvular Heart Disease, Cardiac Surgery and Arrhythmias, Cardiac Surgery and VHD, Interventions and Structural Heart Disease

Keywords: Cardiac Surgical Procedures, Heart Valve Diseases, Heart Valve Prosthesis, Hospital Mortality, Outcome Assessment (Health Care), Secondary Prevention, STS/ACC TVT Registry, Transcatheter Aortic Valve Replacement


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