Surgical treatment of patients with aortic valve disease complicated with moderate functional mitral regurgitation and heart failure with midrange ejection fraction: a cohort study

Background: Controversies exist on the treatment of moderate functional mitral regurgitation (FMR) in patients with severe aortic valve disease undergoing the aortic valve replacement (AVR). While a substantial proportion of these patients can be complicated with heart failure with midrange ejection fraction (HFmrEF), established studies show that the latter might compromise the patient outcome. This study was aimed to evaluate the prognostic value of concomitant mitral valve surgery during AVR in patients with severe aortic valve disease followed by moderate FMR and HFmrEF. Methods: A total of 78 consecutive patients were retrospectively recruited. Patients were divided into control (isolated AVR) and treatment (AVR + mitral valve surgery) groups. Follow-up outcomes were compared by Kaplan-Meier method, followed by multiple adjustment with inverse probability treatment weighting (IPTW) analysis. The primary outcome was the occurrence of major adverse cardiovascular and cerebrovascular events (MACCE). Results: Thirty-six patients received isolated AVR, while 42 received AVR with mitral valve repair or replacement. The median follow-up time was 28.7 months. Unadjusted analysis showed that there was no significant difference in the rate of MACCE between the two groups [hazard ratio (HR): 1.14, 95% confidence interval (CI): 0.48-2.69, P-logrank=0.770], which was sustained in IPTW analysis [HR: 1.64, 95% CI: 0.59-4.55, P-logrank=0.342]. In addition, while concomitant mitral valve surgery improved follow-up FMR more completely (P=0.026) in the IPTW analysis, the ejection fraction was comparable between the two groups (P=0.276). Furthermore, IPTW analysis also showed that mitral valve surgery was associated with the increased risk of postoperative acute kidney injury (P=0.007). Conclusions: In patients with aortic valve disease followed by moderate FMR and HFmrEF, mitral valve surgery concomitant to AVR may not bring extra benefit in the MACCE-free survival and the improvement of HFmrEF. However, while concomitant mitral valve surgery has priority on the complete improvement of FMR, it might increase the risk of postoperative acute kidney injury.