Safety and Diagnostic Value of Intravenous Dipyridamole Thallium Scintigraphy in Patients with Suspected Coronary Artery Disease

Abstract

Thallium-201 myocardial perfusion imaging (T1-201 MPI) performed in patients after maximum exercise is widely used to evaluate patients with suspected coronary artery disease (CAD). Intravenous dipyridamole (DP), by virtue of its potent coronary vasodilation effect, can produce results similar to those of maximum exercise. To evaluate the safety and diagnostic usefulness of intravenous DP thallium imaging, 100 patients with suspected or known CAD were studied. Thirty-two patients were referred for diagnostic cardiac catheterization and these patients also underwent exercise Tl-201 MPI. The sensitivity and specificity of Tl-201 MPI studies were 92% and 83%, respectively, for DP; and 88% and 83%, respectively, for exercise Tl-201 studies. Of the 100 patients studied, 44 had some adverse effects. Noncardiac side effects were transient and required no treatment. Chest pain was the most common cardiac side effect, occurring in 24 patients, and ischemic electrocardiograpic changes were seen in 14 patients. Intravenous aminophylline (125 mg) was used in 13 patients to reverse these effects. No patient suffered myocardial infarction or severe arrhythymia, and none died. We concluded that Tl-201 MPI after coronary vasodilation with intravenous dipyridamole is a safe and better noninvasive procedure for the evaluation of CAD in patients who are unable or not expected to achieve an adequate exercise level.