SAFETY OF EARLY INTRAVENOUS DIPYRIDAMOLE TECHNETIUM 99M SESTAMIBI SPECT MYOCARDIAL PERFUSION IMAGING AFTER UNCOMPLICATED FIRST MYOCARDIAL-INFARCTION

We assessed the safety of early (2 to 4 days) intravenous dipyridamole infusion in conjunction with technetium 99m sestamibi tomographic myo cardial perfusion imaging in patients with first myocardial infarction (Mi). Early risk stratification with myocardial perfusion imaging of patients after acute MI may be useful to identify patients who either require further evaluation or may be safely discharged. Because of min imal hemodynamic effects, intravenous dipyridamole may be a safe means of producing hyperemia for myocardial perfusion imaging. Stable patie nts with first acute MI who met entry criteria were randomized (3:1) t o either intravenous dipyridamole infusion (0.56 mg/kg over a 4-minute period) 48 to 96 hours after onset of symptoms or a control (no test) group. Adverse cardiac events [unstable angina, recurrent MI, or card iac death) were evaluated during and 24 hours after the dipyridamole i nfusion and during the corresponding 24 hours for the control group. T wo hundred eighty-four patients received dipyridamole infusion a mean time of 3.3 +/- 0.7 days after MI. There were no adverse clinical even ts either during or immediately after the infusion. During the 24 hour s after infusion, three patients had symptoms of unstable angina pecto ris, one patient had a recurrent MI, and no patients died. The earlies t event occurred 4.2 hours after the dipyridamole infusion. Three pati ents had unstable angina pectoris, whereas no patients had either recu rrent MI or died in the control group. There were no statistically sig nificant differences between the two groups. in a multicenter trial, d ipyridamole infusion administered early after the first acute MI resul ted in no increased evidence of cardiac events either immediately or 2 4 hours after the procedure compared with a control group. Therefore i ntravenous dipyridamole can be safely used as a pharmacologic vasodila tor For myocardial perfusion imaging soon after uncomplicated MI.