Positive high-dose dipyridamole echocardiography test after acute myocardial infarction is an excellent predictor of cardiac events

Abstract

To determine the prognostic value of the high-dose (0.84 mg/kg over a 10-minute period) dipyridamole echocardiography test (DET) after a first acute myocardial infarction (AMI) in comparison with clinical, electrocardiographic, echocardiographic, and angiographic variables, follow-up data over an average period of 16 months were obtained in 93 consecutive patients. There were 41 total cardiac events (TCE): one death, two reinfarctions, 13 postinfarction anginas, five percutaneous transluminal coronary angioplasty procedures, and 20 coronary artery bypass graft procedures. TCE without revascularization procedures were considered adverse cardiac events (ACE). The DET result was positive in 28 of 41 patients with TCE and in only 4 of 52 patients without TCE ( p < 0.001). The sensitivity, specificity, and accuracy of positive DET in predicting TCE were 68%, 92%, and 82%, respectively. According to Cox's proportional regression model the best predictor of TCE was positivity of DET ( p = 0.002, relative risk ratio 4.3), followed by multivessel coronary artery disease ( p = 0.018, relative risk ratio 2.9) and patent infarct-related artery ( p = 0.042, relative risk ratio 2.9). DET was positive in 12 of 16 patients with ACE and 20 of 77 patients without ACE ( p = 0.001). The sensitivity, specificity, and accuracy of DET in predicting ACE were 75%, 74%, and 74%, respectively. According to Cox's proportional regression model significant predictors of ACE were positivity of DET ( p = 0.002, relative risk ratio 29.4) and ejection fraction ≤40% at the time of DET ( p = 0.017, relative risk ratio 22.2). These data indicate that the positivity of DET is an excellent predictor of cardiac events after AMI and is more powerful as a predictor than the extent of coronary artery disease, suggesting its ability to identify “functionally” critical stenosis. A positive DET result can identify high-risk patients after AMI who should undergo coronary angiography and may benefit from revascularization procedures.