Prognostic value of high dose dipyridamole echocardiography in patients with chronic coronary artery disease and preserved left ventricular function

Objectives. The prognostic value of dipyridamole echocardiographywas assessed in patients with chronic coronary artery disease and preserved left ventricular function. Background. Few data are available on the prognostic value of dipyridamole echocardiography in patients with a low risk of cardiac events. Methods. Two hundred sixty-eight consecutive patients with stable, proven or suspected coronary artery disease and ejection fraction greater than or equal to 0.40 underwent high dose (up to 0.84 mg/kg body weight) dipyridamole echocardiography, In 204 patients definite exercise electrocardiographic (EGG) results were also available. Results. During a mean (+/-SD) follow-up period of 16 +/- 8 months (range 6 to 36), 33 spontaneous events occurred: 15 "hard" events (cardiac death [n = 6], myocardial infarction [n = 9]) and 18 "soft" events (unstable angina). Events occurred more frequently in patients with positive findings on dipyridamole echocardiography (59% vs, 3%, p < 0.001; hard events 24% vs. 2%, p < 0.01), A positive response at the low dose (up to 0.56 mg/kg) identified patients with a high incidence of hard events (7 of 16 patients, sensitivity 50%, specificity 96%), In patients with an exercise EGG, a comparable sensitivity for cardiac events was found (89% vs, 93%, p = NS), but dipyridamole echocardiography was more specific (91% vs, 61%, p < 0.01). A positive response on the low work load exercise ECG (<8 min) and a positive response to low dose dipyridamole echocardiography had similar accuracy (82% vs. 90%, p = NS), Cox analysis identified dipyridamole echocardiography as the best predictor of cardiac events (odds ratio [OR] 20.9, 95% confidence interval [CI] 10.8 to 37.9); the highest risk of hard events was found in patients with a positive response to low dose dipyridamole echocardiography (OR 25.4, 95% CI 12.2 to 54.1). Conclusions. In patients with chronic coronary artery disease and a low incidence of cardiac events, dipyridamole echocardiography was effective in prognostic stratification, and positive low work load exercise ECG results were a reliable predictor of subsequent events. Consequently, dipyridamole echocardiography should be considered a complementary tool in the presence of high work load positivity or ambiguous exercise ECG results.