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

The prognostic significance of moderate secondary mitral regurgitation (MR) after optimized guideline-directed medical therapy (GDMT) in heart failure (HF) remains uncertain.

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.

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.

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.