Background: Functional mitral regurgitation (MR) is a factor affecting prognosis of patients with chronic left ventricular (LV) dysfunction. The aim of the study was to investigate whether the evaluation of plasma N-terminal protype-B natriuretic peptide (NT-proBNP) concentrations is useful for prognostic assessment of patients with functional MR due to either ischemic or nonischemic chronic LV dysfunction.
Methods: Echocardiograms were obtained in 207 patients with chronic LV dysfunction (ejection fraction <or=45%) and secondary MR at color flow imaging. The NT-proBNP was measured at the time of the index echocardiogram. The MR was graded as mild when a small central jet <4 cm(2) or <20% of left atrial area or a vena contracta width <0.3 cm was present. It was considered moderate in the presence of signs of more-than-mild MR without criteria for severe MR. A vena contracta width >or=0.7 cm raised MR grade to severe. Median follow-up duration was 29 months.
Results: The NT-proBNP levels increased significantly with MR severity. At multivariate analysis, NT-proBNP was an independent predictor of cardiac death (hazard ratio 2.17, CI 1.10-4.30, P = .026) and the most powerful predictor of cardiac death or heart failure-related hospitalization (hazard ratio 3.19, CI 1.89-5.37, P < .0001). A progressively worse outcome was apparent when patients were stratified by a graded increase in MR severity and by quartiles of NT-proBNP levels. Increased NT-proBNP concentrations and more-than-mild MR identified patients with the highest risk of cardiac mortality.
Conclusion: Assessment of plasma NT-proBNP allows for stratifying patients with functional MR regardless of their degree of valvular incompetence. Even in case of only mild or moderate MR, but increased NT-proBNP, patients have to face poor outcome.