Regadenoson Stress Real-Time Myocardial Perfusion Echocardiography for Detection of Coronary Artery Disease: Feasibility and Accuracy of Two Different Ultrasound Contrast Agents

Background: The aim of this study was to compare the efficacy of myocardial perfusion (MP) and wall motion (WM) analysis obtained with real-time myocardial contrast echocardiography (RTMCE) and two widely used contrast agents in detecting coronary artery disease after injection of the vasodilator regadenoson. Methods: One hundred fifty patients were studied at two academic centers using regadenoson (400-mu g intravenous bolus) vasodilator stress RTMCE (7.5% Optison infusion [n = 50] or 1.5% Definity infusion [n = 100]). Both MP and WM with RTMCE were analyzed at rest and after regadenoson bolus. Comparisons of WM and MP sensitivity, specificity, and accuracy were made. Quantitative angiography was performed in all patients within 1 month of the regadenoson stress study (> 50% and > 70% diameter stenosis was considered significant). Reviewers were blinded to all clinical and quantitative angiographic data. Results: Rate-pressure product after regadenoson was higher in Optison than Definity patients (P =.004). Using a 50% diameter stenosis on quantitative angiography as a reference standard, overall sensitivity, specificity, and accuracy for combined WM and MP analysis were not different for both agents (Optison, 77%, 64%, and 73%; Definity, 80%, 74%, and 78%; P = NS). The sensitivity, specificity, and accuracy of WM analysis alone for Optison were 68%, 71%, and 69% compared with 60%, 72%, and 66% for Definity (P = NS). Adding MP analysis improved the sensitivity and accuracy of Definity for detecting both > 50% and > 70% stenoses (P <.001 vs WM), while MP analysis did not improve the sensitivity of Optison for detecting either > 50 or > 70% stenoses. Conclusions: RTMCE during regadenoson stress using either Optison or Definity is a rapid and effective method for the detection of coronary artery disease. The ability of MP imaging to improve WM accuracy may depend on the rate-pressure product achieved.