LONG-TERM RISK STRATIFICATION WITH DIPYRIDAMOLE IMAGING

This study was undertaken to assess the reliability of clinical parame ters and dipyridamole-thallium 201 images for predicting the occurrenc e of future cardiac events (nonfatal myocardial infarction or cardiac death). Dipyridamole myocardial perfusion imaging is routinely perform ed in patients who have possible or known coronary disease and a low e xercise tolerance. A total of 753 patients underwent clinical assessme nt and semiquantitative dipyridamole-Tl-201 imaging and were followed up as outpatients. Patients who underwent coronary revascularization d uring the follow-up period were excluded from the study because the de cision to intervene would have been based at least in part on the test itself. There were 82 cardiac events and 54 noncardiac deaths, and 11 patients were lost to follow-up after a mean follow-up of 15 months. With use of a quantitative index reflecting the amount of jeopardized myocardium, patients could be stratified by dipyridamole imaging into subsets with coronary morbidity and mortality rates ranging from 1% to 89%, (p = 0.0001). When clinical and scintigraphic variables were sub jected to backward stepwise logistic regression analysis, the signific ant predictors of cardiac events were the jeopardized myocardium index by scintigraphy (p < 0.0001), left ventricular hypertrophy on the ele ctrocardiogram (p = 0.0009), and transient dipyridamole-induced left v entricular cavitary dilatation (p = 0.0073). Quantitative dipyridamole -Tl-201 imaging appears to be a powerful predictor of future cardiac e vents in patients with coronary disease and a low exercise tolerance a nd is a potentially useful contributor to risk-profile assessment and to the treatment of these patients.