Prognostic Value of Pharmacologic Stress Echocardiography in Patients With Idiopathic Dilated Cardiomyopathy: A Prospective, Head-to-Head Comparison Between Dipyridamole and Dobutamine Test

Abstract

Background Inotropic reserve identified by dobutamine or dipyridamole stress echocardiography is associated with a better outcome in patients with idiopathic dilated cardiomyopathy (DCM), although the relative prognostic value of each remains unsettled. The purpose of the present study was to assess the relative prognostic value of dobutamine versus dipyridamole stress echocardiography for the prediction of all-cause death in patients with idiopathic DCM. Methods and Results Eighty-seven patients (63 were male, aged 54 ± 12 years) with DCM and an ejection fraction less than 35% underwent both dipyridamole and dobutamine stress echocardiography on different days and in a random order. In all patients, wall motion score index and ejection fraction were evaluated at baseline and peak stress. All patients were followed up for an average of 52 months. All-cause death was identified as the prognostic end point. During the follow-up, 26 all-cause deaths occurred (29.8%). On multivariate analysis, either dobutamine echocardiography (relative risk 0.299; P = .02; 95% confidence interval 0.084–0.835) or dipyridamole echocardiography (relative risk 0.161; P < .00; 95% confidence interval 0.07–0.394) added significantly to a prognostic model based on clinical and resting echocardiographic variables. Survival was 83% in patients with dobutamine and 84% in patients with dipyridamole-induced contractile reserve. Conclusions Dobutamine and dipyridamole stress echocardiography have similar feasibility and prognostic accuracy in DCM risk stratification.