Effect of β-blocker on patients with moderate functional mitral regurgitation undergoing surgical aortic valve replacement

Abstract

Aims: The optimal treatment for severe aortic valve disease complicated with moderate function mitral regurgitation (FMR) remains controversial. Although isolated surgical aortic valve replacement (SAVR) is reasonable, previous studies also show that moderate FMR might deteriorate after surgical treatment and result in poorer prognosis. Because the left ventricular remodelling plays a critical role in the development of FMR, these patients might potentially benefit from the administration of β-blocker (BB). Unfortunately, relevant clinical evidence is lacking. This study aimed to investigate the impact of post-operative administration of BB on the outcomes of moderate FMR patients undergoing isolated SAVR.

Methods: In this single-centre cohort study, patients who underwent isolated SAVR and complicated with pre-operative moderate FMR during 2010 and 2019 at our centre were retrospectively recruited. Patients were divided into two groups according to postoperative administration of BB (BB group vs. control group). The cumulative survival rates were calculated using the Kaplan-Meier method and tested by the log-rank test, followed by inverse probability treatment weighting (IPTW) analysis to further control the between-group imbalances. The primary outcome was the major adverse cardiovascular and cerebrovascular events (MACCE), a composite endpoint of all-cause death, repeat heart valve surgery, non-fatal myocardial infarction, stroke, and hospitalization for heart failure.

Results: A total of 165 patients were enrolled, 57 (34.6%) of whom were female, and the mean age was 59.2 ± 12.2 years. Eighty (48.5%) patients received post-operative BB therapy. The median follow-up time was 18.4 months. The administration of BB was not associated with lower risk of MACCE [hazard ratio (HR): 0.68, 95% confidence interval (CI): 0.29-1.62, P = 0.388] or all-cause death (HR: 1.03, 95% CI: 0.30-0.56, P = 0.967). In the IPTW dataset, the total number of patients were 326.89, and the outcomes regarding the risk of MACCE (HR: 0.79, 95% CI: 0.31-1.97, P = 0.607) and all-cause death (HR: 1.33, 95% CI:0.35-5.05, P = 0.674) were in line with the unmatched analysis. The follow-up echocardiographic results were available for 72.2% of the overall cohort, and the use of BB was observed to be associated with higher improvement rate of follow-up FMR according to the IPTW analysis (92.2% vs. 98.3%, P = 0.033).

Conclusions: The administration of BB after SAVR was not associated with lower risk of MACCE for patients of severe aortic valve disease complicated with moderate FMR, but was potentially beneficial for improving FMR.

Keywords: Beta-blocker; Moderate functional mitral regurgitation; Severe aortic valve disease; Surgical aortic valve replacement.