Comparison of Myocardial Contrast Echocardiography and Low-Dose Dobutamine Stress Echocardiography in Predicting Recovery of Left Ventricular Function After Coronary Revascularization in Chronic Ischemic Heart Disease

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Abstract
Background Dobutamine stress echocardiography (DSE) and myocardial contrast echocardiography (MCE) can predict recovery of left ventricular function after myocardial infarction. DSE also has been shown to predict left ventricular functional recovery after revascularization in chronic ischemic heart disease, whereas MCE has not been evaluated in such patients. This study was performed to compare DSE and MCE in the prediction of left ventricular functional recovery after revascularization in patients with chronic ischemic heart disease. Methods and Results MCE and DSE were performed in 35 patients with chronic coronary artery disease and significant wall motion abnormalities (mean ejection fraction, 0.36±0.09). Regional wall motion was scored by use of a 16-segment model wherein 1=normal or hyperkinetic, 2=hypokinetic, 3=akinetic, and 4=dyskinetic. Each segment was evaluated for contractile reserve by DSE and perfusion by MCE. Revascularization (coronary artery bypass graft [n=13] and percutaneous transluminal coronary angioplasty [n=10]) was successful in 23 patients. Follow-up echocardiograms were done to assess wall motion 30 to 60 days later. In 238 segments with resting wall motion abnormalities, perfusion was more likely to present than contractile reserve (97% versus 91%, P<.02). Revascularization resulted in functional recovery in 77 of 95 hypokinetic segments (81%) but only 18 of 57 akinetic segments (32%, P<.0001). DSE and MCE were not significantly different in predicting functional recovery of hypokinetic segments. In akinetic segments, DSE and MCE had similar sensitivities (89% versus 94%, respectively) and negative predictive values (93% and 97%, respectively) in predicting functional recovery. However, DSE had a higher specificity (92% versus 67%, P<.02) and positive predictive value (85% versus 55%, P<.02) than MCE in predicting functional recovery. Conclusions Both contractile reserve by DSE and perfusion by MCE are predictive of functional recovery in hypokinetic segments after coronary revascularization in patients with chronic coronary artery disease. In akinetic segments, myocardial perfusion by MCE may exist in segments that do not recover contractile function after revascularization. Thus, contractile reserve during low-dose dobutamine infusion is a better predictor of functional recovery after revascularization in akinetic segments than perfusion.