Practice Change in Surgical Treatment Strategies for Ischaemic Mitral Regurgitation and Late Outcomes.

Abstract

Background: Ischaemic mitral regurgitation (IMR) results from dysfunctional myocardial remodelling, which portends a poor clinical prognosis. This study assessed the surgical treatment of IMR and its associations with clinical and echocardiographic outcomes in the context of 2014 reports suggesting non-surgical management of non-severe IMR.

Method: Patients who underwent mitral valve (MV) procedures for IMR at Liverpool Hospital (Sydney, Australia) between 2008 and 2020 were included based on coronary disease and echocardiographic criteria. Data were obtained from patient records and linkage with the Australian Institute of Health and Welfare National Death Index. The primary outcome was the type of MV surgery performed in 2008-2014 and 2015-2020. Secondary outcomes were survival and freedom from combination of mortality and congestive heart failure (CHF) readmission, comparing MV repair and MV replacement and the outcomes for two periods by MV procedure.

Results: Of 106 patients treated surgically for IMR, 78 had MV repair (59 in 2008-2014, 19 in 2015-2020) and 28 had MV replacement (14 in 2008-2014, 14 in 2015-2020). Patients were followed up for 7.2 years (interquartile range 5.2-9.1). Compared to 2008-2014, there was a reduced proportion of MV procedures for IMR (4.2% and 2.0%; p<0.001) and MV repair for IMR (80.8% and 57.6%; p=0.012) post-2014. Freedom from a combination of mortality and CHF readmission over 10 years was significantly better in the MV repair than in the MV replacement group (log rank p<0.001). Over 5 years, freedom from mortality and the combination of mortality and CHF readmission were similar in both periods (log rank p=0.675 and p=0.433). In the earlier period, freedom from combined outcome was better in the MV repair group than the MV replacement group (log rank p<0.001) but not different in the second period (log rank p=0.149). Mitral regurgitation recurrence was less in the later period (25.8% and 3.6%; p=0.013).

Conclusions: The proportion of MV procedures and MV repairs performed for IMR declined significantly after 2014, indicating a significant change in practice towards conservative surgical correction of IMR. The combined long-term outcomes were unchanged after the change in practice, but the incidence of mitral regurgitation recurrence was significantly improved.