Objective: This study aims to investigate the prognostic value of mitral valve regurgitation (MR) in patients hospitalized with heart failure with mildly reduced ejection fraction (HFmrEF). 

Background: Limited data regarding the prognostic impact of MR in patients with HFmrEF is available. 

Methods: A large retrospective registry was used including all consecutive hospitalized patients with HFmrEF (i.e., left ventricular ejection fraction (LVEF) 41 – 49%) from 2016 to 2022 according to current European guidelines. The prognostic impact of patients with moderate or severe MR was compared to patients without (non-MI). The primary endpoint was the first heart-failure related re-hospitalization at 3 years. Secondary endpoints comprised amongst others in-hospital mortality. Kaplan-Meier, uni- and multivariable Cox regression analyses were applied for statistics.

Results: 803 consecutive patients with HFmrEF were included. The prevalence of moderate to severe MR was 18% (moderate 13%; severe 5%). Patients with moderate to severe MR showed significantly higher aminoterminal pro-brain natriuretic peptide (NT-pro BNP) levels compared to non-MR (medians 11330 pg/ml vs. 6144 pg/ml; p=0.007). HFmrEF patients with moderate to severe MR were associated with an increased risk of heart-failure related re-hospitalization at 3 years (15% vs. 8%; log rank p=0.003; HR= 2.124; 95% CI 1.285 - 3.513; p=0.003), which was still observed after multivariable adjustment (HR= 1.957; 95% CI 1.109 - 3.453; p=0.020). Finally, in-hospital mortality was not affected by concomitant MR (5% vs. 3%; p=0.341).

Conclusions: Moderate to severe MR deteriorates prognosis in HFmrEF patients.