Background: Idiopathic dilated cardiomyopathy frequently coexists with anemia and high plasma NT proBNP levels. However, the prognostic impact of these features on the disease course is uncertain, especially in patients with normal renal function.
Methods: Forty-seven patients with idiopathic dilated cardiomyopathy with sinus rhythm and normal renal function were prospectively followed for a mean 25+/-18 months period. Clinical end points were death (sudden cardiac death and deaths because of worsening heart failure) and cardiac transplantation. Prognostic impact of NT proBNP levels, anemia, echocardiographic and clinical parameters on the clinical end points was evaluated with Kaplan-Meier survival analysis. Cut-off values of hemoglobin and plasma NT proBNP levels for predicting end points were determined by receiver operating curve analysis.
Results: Twenty-eight patients (59.6%) suffered clinical end points. The patients who suffered clinical end points were anemic (P=0.002), had lower systolic (P<0.003) and diastolic (P<0.0001) blood pressures, and higher NYHA functional classes (P=0.005), lower left ventricle ejection fractions (P=0.003), higher E/A ratios (P=0.001), shorter E-wave deceleration times (P=0.001), isovolumetric relaxation times (P=0.05) and pulmonary acceleration times (P=0.004), and higher plasma NT proBNP levels (P<0.0001). Anemic patients had more clinical end points (P=0.002). In univariate analysis the prognostic predictors of life expectancy were log NT proBNP, anemia, NYHA functional class, systolic blood pressure, left ventricle ejection fraction, and E-wave deceleration time. However, multivariate analysis revealed only plasma NT proBNP as independent predictor of clinical end points.
Conclusion: Tracking plasma NT proBNP levels is a useful strategy during routine follow-ups of patients with nonischemic dilated cardiomyopathy. Its predictive value for prognosis needs more evaluation in larger controlled studies. In addition, the importance of anemia in those patients needs more study.