Risk stratification in patients with dilated cardiomyopathy: contribution of Doppler-derived left ventricular filling

Abstract

Dilated cardiomyopathy (DCM) is a major cause of mortality among patients with heart failure. The aim of the present study was to investigate the independent contribution of Doppler-derived left ventricular (LV) filling to the prediction of survival in patients with DCM, of either ischemic or nonischemic origin, and to derive a simple risk stratification score based on easily available clinical and echocardiographic parameters. We followed 197 consecutive patients (159 men, mean age 60 ± 13 years) with an echocardiographic diagnosis of DCM (LV end-diastolic dimension >60 mm, fractional shortening <25%) over an average period of 62 ± 13 months. The presumed etiology of DCM was ischemic in 52% of the patients. During follow up, 69 patients died of cardiac causes and 41 required transplantation. At 5 years, overall cardiac event-free survival was 55% and freedom from death or heart transplantation was 43% (compared with 86% for the 5-year age- and sex-adjusted survival rate in our country). Kaplan-Meier survival curves generated for different thresholds of the peak E velocity and the E/A ratio indicated significant worsening of prognosis with increasing values of these parameters in both ischemic and nonischemic patients. Using Cox stepwise regression analyses, age (chi-square to remove 24.4; p <0.001), peak E velocity (chi-square to remove = 18.9; p <0.001), LV ejection fraction (chi-square to remove 6.4; p <0.011), and systolic blood pressure (chi-square to remove 4.5; p = 0.034) independently predicted cardiac deaths, whereas New York Heart Association (NYHA) functional class (chi-square to remove 48.5; p <0.001), LV ejection fraction (chi-square to remove 19.1; p <0.001), E/A ratio (chi-square to remove 10.8; p <0.001), and systolic blood pressure (chi-square to remove 5.8; p <0.016) were independently associated with cardiac death or need for transplantation. Based on these parameters, a risk score was elaborated, which allowed appropriate classification of each individual patient into low- (5-year survival rate of 72%), intermediate- (46% survival rate), and high-risk groups (11% survival rate). In conclusion, our data show that among the noninvasive parameters commonly available in patients with either ischemic or nonischemic DCM, age, the NYHA functional class, the LV ejection fraction, the systolic blood pressure, the peak E velocity, and the E/A ratio provide relevant and independent information regarding the risk of cardiac death or the need for heart transplantation.