DOI: 10.1161/circ.148.suppl_1.17900 ISSN: 0009-7322

Abstract 17900: Target Trial Emulation: Evaluating Cardiac Rehabilitation After TAVR

Merilyn Varghese, Issa Dahabreh, Yang Song, Jiaman Xu, Alexis L Beatty, Kevin McConeghy, Robert W Yeh, Laurence Sperling, Gregg C Fonarow, Steven J Keteyian, Wen-Chih H Wu, Dhruv S Kazi
  • Physiology (medical)
  • Cardiology and Cardiovascular Medicine

Introduction: Effectiveness of cardiac rehabilitation (CR) after transcatheter aortic valve replacement (TAVR) has not been examined in randomized trials. We used a novel causal inference approach called target trial emulation to evaluate whether participation in CR after TAVR reduces all-cause mortality.

Methods: We emulated a target trial among Medicare beneficiaries age≥ 65 years who had undergone a TAVR from October 2016 through September 2019. The intervention was starting CR within 90 days of discharge (time 0) and the outcome was death from any cause. We created two exact copies of each patient’s data (“clones”) and assigned one clone to the control arm and the other to the intervention arm. This eliminated baseline confounding and immortal time bias. Each clone was censored when not consistent with the assigned treatment strategy (e.g., when a control clone initiated CR). Inverse probability weights accounted for potentially informative censoring. Falsification endpoints examined residual confounding.

Results: Among 62,628 Medicare beneficiaries eligible for CR after TAVR, mean age was 80 years, and 43% were women. Of these, 28% initiated CR within the 90-day grace period. After adjusting for demographic, clinical, social, and economic differences, all-cause mortality at 2 years was lower in the CR arm than in the no CR arm (HR 0.74, 95% CI 0.63-0.87, p<0.01) (Figure). Falsification endpoints suggested some residual confounding but absolute differences between the two groups were small.

Conclusion Fewer than 1 in 3 eligible patients receive CR after TAVR. In the first-ever target trial emulation of CR in patients undergoing TAVR, patients who initiate CR had lower rates of all-cause death. Ongoing work will examine additional approaches to account for residual confounding and use alternative quasi-experimental study designs. If replicated, our findings suggest that innovation in CR access and delivery is needed to enhance uptake after TAVR.

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