Impact of severe mitral regurgitation on patients with 'De Novo' heart failure and reduced ejection fraction: baseline characteristics and survival analysis

Abstract Introduction "De novo" heart failure with reduced ejection fraction (HFrEF) is a prevalent clinical condition associated with high morbidity and mortality. The prevalence of severe mitral regurgitation (MR) at diagnosis, the characteristics of this subgroup of patients, and its prognostic impact remain unknown. Methods A retrospective analysis was performed using a registry of consecutive patients hospitalized for "de novo" HFrEF (LVEF ≤ 40%). Patients were divided into two groups based on the presence or absence of severe MR in the pre-discharge echocardiogram. Baseline characteristics were compared between the two groups. The median follow-up was 15 months, with an interquartile range of 7 to 22 months. The Kaplan-Meier method was used to evaluate overall mortality, heart failure events during follow-up (hospitalizations and emergency visits), and the combined endpoint of mortality and heart failure events. Results Regarding baseline characteristics, the group with severe MR at discharge was associated with a lower prevalence of tachycardiomyopathy as the underlying etiology (p = 0.005) and showed a higher, albeit borderline, association with ischemic etiology (p = 0.07). Additionally, the severe MR group had a larger left ventricular end-diastolic diameter (p = 0.004) and a higher prevalence of severe tricuspid regurgitation (p 0.001). Hospital stays were longer in patients with severe MR (11.8 vs. 9.1 days, p = 0.005), and loop diuretic use was higher both at discharge (p = 0.07) and after titration (p 0.001) in this group. Kaplan-Meier survival analysis revealed significant differences in the incidence of heart failure events during follow-up between the groups (p = 0.016). However, there were no differences in overall mortality (p = 0.276), and the combined endpoint of mortality and heart failure events was borderline significant (p = 0.083). Conclusions In patients hospitalized for "de novo" HFrEF, severe MR is more frequently associated with ischemic etiology and less frequently with tachycardiomyopathy. This condition is linked to a higher risk of heart failure events during follow-up, underscoring the importance of evaluating and adequately managing MR in patients with "de novo" HFrEF.