Impact of discharge beta-blocker therapy on outcomes after isolated coronary artery bypass grafting in patients with moderate ischemic mitral regurgitation
L X Chen, W Zhao, W FengAbstract
Background
Evidence on heart failure pharmacotherapy after surgery for ischemic mitral regurgitation is limited. The prognostic relevance of beta-blocker therapy after isolated coronary artery bypass grafting in patients with moderate ischemic mitral regurgitation remains uncertain.
Purpose
To evaluate the association between discharge beta-blocker therapy and long-term clinical outcomes, and to assess changes in mitral regurgitation severity during echocardiographic follow-up.
Methods
This retrospective single-centre cohort study included patients with moderate ischemic mitral regurgitation undergoing isolated coronary artery bypass grafting between 2009 and 2024. Patients were grouped by discharge beta-blocker prescription (beta-blocker vs no beta-blocker). The primary endpoint was major adverse cardiovascular and cerebrovascular events, defined as a composite of all-cause mortality, non-fatal myocardial infarction, non-fatal stroke, rehospitalisation for heart failure, and repeat mitral valve surgery. Kaplan–Meier curves were compared using the log-rank test. Inverse probability of treatment weighting was applied to mitigate confounding; to improve weight stability, weights were trimmed at the 1st and 99th percentiles. Covariate balance was assessed using standardised mean differences, with <0.1 indicating adequate balance.
Results
A total of 484 patients were included (beta-blocker group n=414; no beta-blocker group n=70). After weighting, baseline covariates were well balanced (all standardised mean differences <0.1). Over a median follow-up of 32.0 months (IQR 12.7–54.1), there were no significant between-group differences in the incidence of major adverse cardiovascular and cerebrovascular events (unweighted P=0.129; weighted P=0.525) or all-cause mortality (unweighted P=0.160; weighted P=0.561). Echocardiographic follow-up was available in 351 patients (72.5%) at a median of 11.6 months (IQR 4.7–13.3), showing no between-group differences in mitral regurgitation severity, improvement, or progression.
Conclusion(s)
In patients with moderate ischemic mitral regurgitation undergoing isolated coronary artery bypass grafting, discharge beta-blocker therapy was not associated with improved major adverse cardiovascular and cerebrovascular events or survival, and did not appear to influence mitral regurgitation severity on follow-up echocardiography. Prospective studies are warranted to clarify optimal post-operative medical therapy in this population.For image description, please refer to the figure legend and surrounding text.For image description, please refer to the figure legend and surrounding text.