Long-term results of mitral repair for functional mitral regurgitation in idiopathic dilated cardiomyopathy

Objectives: While the results of mitral repair in ischaemic mitral regurgitation have been repeatedly reported, less data are available about the outcome of surgical repair of functional mitral regurgitation (FMR) in idiopathic dilated cardiomyopathy (iDCM) which represents the topic of this study. Methods: Fifty-four iDCM patients (mean age 63 ± 10.5 years) underwent mitral valve repair for severe FMR. Coronary angiography confirmed the absence of coronary disease in all patients. Most of the patients (77.7%) were in New York Heart Association (NYHA) class III-IV. Pre-operative ejection fraction (EF) was 30.4 ± 8.5%, left ventricle end-diastolic diameter (LVEDD) 67.5 ± 7.8mm, left ventricle end-systolic diameter (LVESD) diameter 53.9 ± 8.3mm. Concomitant procedures were atrial fibrillation (AF) ablation (19 patients) and tricuspid repair (17 patients). Follow-up was 100% complete (mean 4.2± 2.5 years, median 4.2 years, range 3.3 months-11.1 years). Results: In-hospital mortality was 5.6%. Actuarial survival at 6.5 years was 69± 8.8%. Patients submitted to successful AF ablation and/ or cardiac resynchronization therapy (CRT) had a significantly better survival (91 ± 7.9 vs 67 ± 9.5%, P= 0.01). Freedom from MR≥3+/4+ was 89.1 ± 5.7% at 6.5 years. Follow-up echocardiography showed a reduction in LVEDD (P<0.0001) and LVESD (P= 0.0003). Mean EF increased to 38.7± 12.4% (P<0.0001). Multivariate analysis identified successful ablation of AF and/or CRT (P= 0.01) and higher preoperative EF (0.03) as predictors of overall survival. Successful ablation of AF and/or CRT (P= 0.02) and lower preoperative systolic pulmonary artery pressure (0.04) were identified as independent predictors of reverse LV remodelling at follow-up. At last follow-up, 86.2% of the patients were in NYHA II or less. Conclusions: Mitral repair for FMR in well-selected iDCM patients is associated with low hospital mortality and significant clinical benefit at late follow-up. Concomitant successful AF ablation and/or CRT provide a major symptomatic and prognostic advantage and should be associated to mitral surgery whenever indicated.