Usefulness of dipyridamole thallium scintigraphy in the diagnosis of coronary artery disease in elderly patients

Abstract

Patients suspected of having coronary artery disease (CAD) underwent dipyridamole thallium scintigraphy, exercise electrocardiography, and coronary angiography. Of the 500 patients studied, 163 were at least 65 years old, and 337 were less than 65 years old. Both CAD and multivessel CAD were more common in elderly than in younger patients (81% vs 69%, p < 0.01 for CAD; and 43% vs 26% p < 0.01 for multivessel CAD). In patients without myocardial infarction, the specificity of exercise electrocardiography was lower among elderly patients than among younger patients (52% vs 61%), but the sensitivity was higher (87% vs 75%). In contrast, both the sensitivity and the specificity of dipyridamole thallium scintigraphy were similar in the two age groups (86% vs 87% and 79% vs 74%). Among patients with myocardial infarction and a positive exercise test, reversible defects were equally common in the two age groups (60% vs 58%). The reversible defects were in areas remote from the area of infarction in half of the patients in both groups. Among patients with negative exercise-test results, reversible defects were more common in elderly patients than in younger patients (57% vs 38%). The reversible defects were in the infarcted area in 71% and 79% of these patients, respectively. These results indicate that dipyridamole thallium scintigraphy is a sensitive and specific method for detecting CAD, independent of age. It is particularly useful in identifying myocardial viability in the infarcted area.