Correlation of preoperative myocardial function, perfusion, and metabolismwith postoperative function at rest and stress after bypass surgery in severe left ventricular dysfunction

Previous studies of dobutamine echocardiography (DE) and positron emission tomography (PET) showed similar accuracy for predicting improvement in rest ing wall motion after revascularization, although limited direct comparativ e data are available. We sought to compare the relative accuracy of detecti ng contractile reserve, ischemia, perfusion, and myocardial metabolism for predicting functional recovery after coronary bypass surgery in 94 consecut ive patients (aged 63 +/- 11 years) with chronic coronary disease and depre ssed left ventricular function (ejection fraction 28 +/- 5%). PET imaging c omprised rest and dipyridamole stress myocardial perfusion images, with flu orodeoxyglucose to define metabolism-perfusion mismatch. A standard dobutam ine-atropine stress was used, with evaluation of low- and peak-dose echocar diographic responses. Regional function was assessed after 13 +/- 16 weeks at rest in 68 patients who underwent isolated coronary bypass operation wit hout evidence of perioperative infarction, and at rest and stress in a subg roup of 29 patients. Concordance between methods for evaluating abnormal se gments (ischemic, viable, and scar) and accuracy of both tests for predicti ng improvement in regional function were identified. Concordance between PE T and DE for identifiying viable or nonviable myocardium was 63% using a 16 -segment model. For predicting improved resting function after surgery, the sensitivity of PET (84%) was superior to DE (69%, p <0.001), but DE was mo re specific (78% vs 37%, p <0.0001) and more accurate (75% vs 53%, p <0.001 ) in predicting recovery at rest. Analysis of postoperative recovery of seg mental function during stress also showed the specificity of DE to exceed t hat of PET (89% vs 32%, p <0.001). The accuracy of DE was enhanced by evalu ation of function during stress (86%, p <0.001), but this was not altered w ith PET (52%, p = NS). Thus, PET is more sensitive than DE in predicting fu nctional recovery, but DE is more specific than PET. Evaluation of left ven tricular functional recovery during stress may be preferable to assessment at rest. (C) 1999 by Excerpta Medica, Inc.