Dipyridamole-Induced Myocardial Ischemia

To the Editor.—  The report by Keltz et al¹ linking oral dipyridamole to myocardial ischemia deserves comment. In my opinion, the clinical information provided does not allow for the conclusion that dipyridamole was the cause of the ischemic episodes. The significance of the one reported case of myocardial infarction with a fatal outcome cannot be determined on the basis of the authors' small series of patients without comparison to a control group.To elucidate further the incidence of myocardial infarction and coronary death resulting from dipyridamole administration, I examined adverseevent data from two large studies of patients treated with dipyridamole (Persantine).In an ongoing multicenter, randomized, double-blind, placebo-controlled study of patients undergoing coronary artery bypass graft surgery, dipyridamole was given at a dosage of 100 mg four times daily for two days preoperatively and continued thereafter. Myocardial infarction and/or coronary death occurred preoperatively in 0.4% (1/259) of the patients