Abstract Body (Do not enter title and authors here): Background:
Transcatheter mitral valve repair (TMVr) is increasingly being used to treat severe mitral regurgitation in patients at high surgical risk. While cardiac rehabilitation (CR) improves outcomes in post-surgical cardiac populations, its benefit after TMVr remains poorly characterized.

Hypothesis:
We hypothesized that outpatient CR following TMVr is associated with improved clinical outcomes compared to no CR.

Methods:
This retrospective cohort study utilized the TriNetX Research Network to identify adult patients who underwent TMVr between January 2014 and December 2023. Patients were grouped by participation in outpatient CR within 30 days of discharge (n=570) versus no CR (n=6,906). Propensity score matching was performed using demographics, comorbidities, medications, and laboratory values, yielding 562 matched pairs. The primary outcomes were all-cause hospitalization, intravenous (IV) diuretic use (as a surrogate for acute heart failure decompensation), repeat TMVr, and all-cause mortality. Hazard ratios (HR) were estimated using Cox proportional hazards models.

Results:
After matching, groups were well balanced (mean age 76 ± 10 years; 44% female). Over a mean follow-up of 330 days, patients in the CR group had a significantly lower rate of IV diuretic use (16.7% vs. 22.2%; HR 0.69, 95% CI 0.53–0.90, p=0.006) and all-cause mortality (11.0% vs. 14.6%; HR 0.71, 95% CI 0.51–0.99, p=0.041). All-cause hospitalizations were numerically lower in the CR group (36.8% vs. 38.6%) but not statistically significant (HR 0.89, 95% CI 0.73–1.07, p=0.209). Repeat TMVr was rare in both groups (1.8% vs. 2.3%, p=0.228).

Conclusion:
Outpatient cardiac rehabilitation after TMVr was associated with a significant reduction in rate of IV diuretic use and mortality, suggesting improved heart failure management. These findings support routine referral to CR programs as part of post-TMVr care pathways.