Prediction of prognosis of patients with idiopathic dilated cardiomyopathy. A comparison of echocardiography with cardiac catheterization.

Abstract

The prognostic values of indices obtained by M-mode and two-dimensional echocardiography (Echo) and by cardiac catheterization (Cathe) were assessed in patients with idiopathic dilated cardiomyopathy. Fifty-one patients with this disorder (38 males and 13 females) were studied for an average of 4.2 years. Of those, 24 died of cardiac causes during follow-up. The overall 5-year survival rate was 49%. Significant differences between the surviving patients and the patients who died were noted in the following indices measured by Cathe: left ventricular end-diastolic volume (LVEDV), left ventricular end-diastolic pressure (LVEDP), ejection fraction (EF), and the cardiac index (CI). The 5-year survival rate in patients with the following index values measured by Cathe at the initial examination were: LVEDV ≥ 150 ml/M² - 29%; LVEDP > 12 mmHg - 35%, EF < 30% - 21%, and CI < 3.0 L/min/M² - 29%. In contrast, the 5-year survival rate in patients with the following parameter values measured by Echo were: left ventricular end-diastolic dimension ≥ 45 mm/M² - 16%; left atrial dimension ≥ 25 mm/M² - 12%; ejection fraction < 30% - 31%; and a relative wall thickness (a ratio of left ventricular posterior wall thickness to left ventricular end-diastolic dimension) ≤ 0.12 - 9%. In assessing the cumulative survival rate, the indices provided by Echo revealed similar values when compared with those obtained by Cathe. The relative wall thickness determined by Echo would be the most reliable parameter for forecasting the 5-year survival rate. In the majority of patients (22/24) who died during the observation period, the relative wall thickness gradually decreased to less than 0.12. Therefore, a relative wall thickness below 0.12 would be the most reliable index for detecting a poor prognosis case. It is concluded that echocardiographic observation of patients with idiopathic dilated cardiomyopathy can provide information useful not only in prognosis but also in assessing the effect of medical treatment.