COMBINED LOW-DOSE DIPYRIDAMOLE-DOBUTAMINE STRESS ECHOCARDIOGRAPHY TO IDENTIFY MYOCARDIAL VIABILITY

Objectives. We sought to evaluate the effects of combined administrati on of infra-low dose dipyridamole and low dose dobutamine on assessmen t of myocardial viability. Background. Low dose pharmacologic stress e chocardiography with either dobutamine or dipyridamole infusion has be en proposed for the recognition of myocardial viability. Methods. Thir ty-four patients with rest wall motion dyssynergy by two-dimensional e chocardiography and with angiographically proved coronary artery disea se underwent in combination with two-dimensional echocardiographic mon itoring: 1) low dose (5 to 10 mu g/kg per min over 3 min) dobutamine i nfusion; 2) infra-low dose (0.28 mg/kg over 4 min) dipyridamole infusi on; 3) combination of infra-low dose dipyridamole infusion immediately followed by low dose dobutamine infusion (combined dipyridamole-dobut amine). Results. Follow-up rest echocardiography was available in 30 p atients. After revascularization, 82 segments showed a contractile imp rovement of greater than or equal to 1 grade, whereas 63 segments rema ined unchanged. The sensitivity of dobutamine, dipyridamole and combin ed dipyridamole-dobutamine for predicting recovery was 72% (95% confid ence interval [CI] 60.9% to 81.3%), 67% (CI 55.8% to 77%) and 94% (CI 86.3% to 97.9%), respectively. The specificity of dipyridamole, dobuta mine and combined dipyridamole-dobutamine was 95% (CI 86.7% to 99%), 9 2% (CI 82.4% to 97.3%) and 89% (CI 78.4% to 95.4%), respectively. The accuracy of the dobutamine, dipyridamole and combined dipyridamole-dob utamine test was 80%, 79% and 92%, respectively (combined dipyridamole -dobutamine vs, dobutamine, p < 0.05; combined dipyridamole-dobutamine vs. dipyridamole, p < 0.01). Conclusions. Infra-low dose dipyridamole added to low dose dobutamine recruits an inotropic reserve in asynerg ic segments that were nonresponders after either dobutamine or dipyrid amole alone and destined to recover after revascularization.