Prognostic Impact of Moderate Secondary Mitral Regurgitation After Optimized Medical Therapy in Heart Failure

BACKGROUND: The prognostic significance of moderate secondary mitral regurgitation (MR) after optimized guideline-directed medical therapy (GDMT) in heart failure (HF) remains uncertain. METHODS: We analyzed 2,468 ambulatory HF patients with paired transthoracic echocardiography at baseline and after 12 months of optimized GDMT. The primary composite was all-cause death or first heart failure hospitalization (HFH). Secondary endpoints included all-cause mortality and recurrent HFHs. RESULTS: Mean age was 66.2 ± 12.5 years, 70.6% were male, and mean baseline LVEF was 36.1% ± 13.6%. At 12 months, 80.5% of patients had no/mild MR, 15.6% had moderate MR, and 3.9% had severe MR. During a median 6.9-year follow-up, 1,240 patients experienced the primary endpoint. Compared with no/mild MR, both moderate and severe MR at 12 months were independently associated with a higher risk of the primary composite endpoint (moderate: hazard ratio [HR] 1.69, 95% confidence interval [CI] 1.47-1.95; severe: HR 1.81, 95% CI 1.44-2.29; both p<0.001). Moderate MR was also independently associated with increased all-cause mortality (HR 1.54, 95% CI 1.32-1.79; p<0.001) and recurrent HFHs (incidence rate ratio [IRR] 2.17, 95% CI 1.81-2.60). HFH rates were 9.03, 20.0, and 26.1 per 100 person-years in patients with no/mild, moderate, and severe MR, respectively. Among patients with moderate MR at 12 months, outcomes did not differ according to baseline MR severity. CONCLUSIONS: In this large-scale study, residual moderate secondary MR after 12 months of optimized GDMT was common and was independently associated with increased long-term mortality and HFHs.