Safety of a High Intravenous One Shot Dose of Dipyridamole for Stress Echocardiography and Thallium Scanning

pp 133-137

Abstract

Background

The safety of a full single high dose of dipyridamole for the evaluation of coronary artery disease has not been well established. The currently protocols of stress echocardiogaphy use fractioned dose (0.56 mgr/kg + 0.28 mgr/kg) and the nuclear medicine protocols use low single dose (0.56 mgr/kg). Hence we realized a prospective study of all the side effects in patients who received the maximal vasodilator dose of dipyridamole (0.84 mgr/kg over4minutes) in one shot infusion during an echo stress test (ESR) or a thallium scanning (TSC).

Methods

700 consecutive studies were performed (455 echostress tests and 245 thallium scannings; 516 males; meanage 61 years): early after acute myocardial infarction, 220 pts; CAD diagnostic purposes, 217pts; unstable angina, 208pts; before major vascular surgery, 39 pts and post CABG, 17 pts. A 240 mgr dose of aminophilline was used as antidote. AMI, ventricular tachycardia/fibrillation, a systole, severe bronchospasm and death were considered major complications.

ResultsAdverse effects were observed in 549 pts (78.4%) and 151 (21.6%) pts remained asymptomatic. Wo-men had a greater incidence of adverse effects than men (93.4% vs81.2%) p < 0.001. The most frequent side effects were ST depression in206 pts (29.4%), angina in 204 pts (29.1%), headache in 182 pts (26%),hypotension in 108 pts (15.4%), tiredness in 98 pts(14%) and flushing in 80 pts (11.4%). Significant adverse reactions were detected in 27 pts (3,9%): atrial fibrillation 2 pts, 2nd degree A-V block 4 pts, left bundle branch block 1 pts and symptomatic hypotension-bradychardia 20 pts. Major complications were no observed.

Conclusions

1) Echo stress testing and thallium scanning with a full single dose of dipyridamol can be safely performed. 2) The numerous side effects were minor, transient and in almost all patients reverted with aminophylline. 3) Women had greater incidence of side effects than men.