Relationship between the severity of functional mitral regurgitation at admission and one-year outcomes in patients hospitalized for acute heart failure with mildly reduced ejection fraction

Abstract Background The epidemiological distribution of functional mitral regurgitation (FMR) in heart failure (HF) and mildly reduced ejection fraction (HFmrEF) patients and its impact on outcomes remains unclear. We attempt to investigate the prognosis of FMR in patients with HFmrEF. Methods The HF center registry study is a prospective, single, observational study conducted at the Second Affiliated Hospital of Shenzhen University, where 2330 patients with acute HF (AHF) were enrolled and 890 HFmrEF patients were included in the analysis. The patients were stratified into three categories based on the severity of FMR: none/mild, moderate, and moderate-to-severe/severe groups. Subsequently, a comparison of the clinical characteristics among these groups was conducted, along with an assessment of the incidence of the primary endpoint (comprising all-cause mortality and readmission for HF) during a one-year follow-up period. Results The one-year follow-up results indicated that the primary composite endpoint occurrence rates in the three groups were 23.5%, 32.9%, and 36.5%, respectively. The all-cause mortality rates in the three groups were 9.3%, 13.7%, and 16.4% respectively. Survival analysis demonstrated a statistically significant difference in the occurrence rates of the primary composite endpoint and all-cause mortality among the three groups ( P < 0.05). Multifactor Cox regression revealed that moderate FMR and moderate-to-severe/severe FMR were independent risk factors for adverse clinical prognosis in HFmrEF patients, with hazard ratios and 95% confidence intervals of 1.382 (1.020–1.872, P = 0.037) and 1.546 (1.092–2.190, P = 0.014) respectively. Conclusions Moderate FMR and moderate-to-severe/severe FMR independently predict an unfavorable prognosis in patients with HFmrEF.