Prognostic implications of functional mitral regurgitation according to the severity of the underlying chronic heart failure: a long-term outcome study.

Aims: To examine the independent prognostic role of functional mitral regurgitation (FMR) and its impact across the severity of chronic heart failure (CHF) in a large population of outpatients with systolic CHF followed at two multidisciplinary clinics.

Methods And Results: Echocardiography was performed upon enrolment in 469 CHF patients. Follow-up for death and heart transplant was updated on January 2007. Five-year transplant-free survival was 82.7% in patients with no or Grade I FMR, 64.4% in Grade II, 58.5% in Grade III, and 46.5% in Grade IV (P < 0.0001). There was a strong graded association between FMR and the long-term risk of death and heart transplant, which remained significant after multivariable adjustment (P = 0.0003). The association between FMR and events was strong and independent in patients with less severe symptoms and in those at lower overall risk based on a propensity score analysis, while it was not significant in patients with more advanced CHF or in the high-risk subgroup (P < 0.0001 for interactions).

Conclusion: This study clarifies previous apparently discrepant results by demonstrating that FMR is an independent determinant of death and heart transplantation only in less severe CHF and in patients with a lower risk profile. This finding indicates that FMR plays a major role in the early phase of CHF, suggesting that this should be the focus of strategies attempting to reduce it.