FMR severity predicts clinical outcome in HF patients
MedWire News: Study findings suggest functional mitral regurgitation (FMR) is strongly associated with clinical outcome in patients with heart failure (HF) related to dilated cardiomyopathy (DCM), independent of left ventricular ejection fraction (LVEF).
The findings are of clinical importance, given that many studies suggest FMR is just a consequence of ventricular remodeling. The decision to treat FMR is based on the assumption that FMR is a key factor in the functional and prognostic impairment of patients with HF independently of LV function.
"FMR should not be considered just a mere consequence of ventricular remodeling but a major predictor for the outcome of patients with HF, suggesting that in patients with severe FMR all therapeutic options of pharmacological and non-pharmacological treatment should be considered," say Andrea Rossi (Civile Maggiore Hospital, Verona, Italy) and co-authors.
In total, 1256 patients (mean age 67 years) with chronic HF due to ischemic or non-ischemic DCM underwent a quantitative evaluation of FMR by measurement of vena contracta (VC), effective regurgitant orifice (ERO), or regurgitant volume (RV). The primary composite endpoint of the study was all-cause mortality or worsening HF.
Severe FMR - defined as having an ERO greater than 0.2 cm2, an RV above 30 ml, or a VC with a diameter over 0.4 cm - was present in 24% of patients, while 49% had mild-to-moderate FMR, and 27% had no FMR.
Only patients with severe FMR had a significantly reduced LVEF, while patients with mild-to-moderate FMR, and those without FMR had similar levels of LV dysfunction (LVEF=29% vs 33% and 34%, respectively).
In contrast, a gradual and significant increase in the prevalence of restrictive mitral filling pattern (RMP; defined as E-wave deceleration time <140 ms) was seen in patients with different degrees of FMR, at 20%, 30%, and 62% for patients without FMR, with mild-to-moderate FMR, and severe FMR, respectively.
Regression analysis showed that severe FMR was significantly associated with a 1.8-fold increase in symptomatic impairment compared with patients without FMR.
After a mean follow-up of 2.7 years, the primary endpoint was reached by 525 patients (300 deaths and 225 hospitalizations for HF). The degree of FMR was significantly associated with adverse outcomes, with 40% of patients without FMR, 25% of patients with mild-to-moderate FMR, and 7% of those with severe FMR surviving free of hospitalization at the end of follow-up.
Compared with patients without FMR the hazard risk (HR) for the primary endpoint associated with severe FMR was 2.7 and with mild-to-moderate FMR was 1.3. Indeed, each single indicator of severe FMR was significantly associated with outcome, with HRs ranging from 1.8 to 2.5.
After adjusting for LVEF and RMP, the risk for severe FMR remained significant, at an HR of 2.0. The independent association of severe FMR with prognosis was confirmed in patients with ischemic and non-ischemic DCM (HR=2.0 and 1.9, respectively).
Writing in the journal Heart, the team concludes: "The demonstration of a clear and powerful association between FMR and prognosis might only suggest that treatment of FMR may improve outcome. However, particularly for the percutaneous approach to FMR, the effectiveness of these procedures can be demonstrated only by randomized trials."
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By Ingrid Grasmo