Abstract 4230: Comparison of Dobutamine-atropine Stress Echocardiography and Magnetic Resonance for Detection of Obstructive Coronary Artery Disease by Assessing Wall Motion and Myocardial Perfusion Abnormalities

Abstract

Background: The analysis of wall motion abnormalities (WMA) with dobutamine stress echocardiography or magnetic resonance is an established method for the detection of myocardial ischemia. Contrast echocardiography has been demonstrated a useful technique for evaluating myocardial perfusion (MP). We test the hypothesis that combination of MP and WMA would improve the diagnosis of coronary artery diseasen (CAD). Objective: To compare the diagnostic accuracy of dobutamine stress real-time myocardial contrast echocardiography (RTMCE) and gadolinium-enhanced magnetic resonance imaging (G-MRI) for detecting CAD by analyzing left ventricular WMA and MP. Methods: We prospectively studied 46 patients (23 males, mean age 58±8 years) referred for coronary angiography, RTMCE and MRI within a maximum interval of two weeks. Protocol used in RTMCE and G-MRI was four-stage dobutamine protocol (10 – 40 mcg/kg/min), with injection of atropine as required to reach 85% of age-adjusted target heart rate. Patients underwent first dobutamine stress RTMCE and then G-MRI using the same doses of dobutamine and atropine. RTMCE was performed using low-mechanical index imaging combined with intravenous commercially available contrast agent (Definity, Bristol-Myers Squibb). Positivity for the stress test was defined as new or worsening WMA or reversible perfusion defects in >2 contiguous segments. Quantitative coronary angiography (QCA) was performed in all patients. CAD was defined as the presence of lesion >50 % in at least one coronary artery territory. Results: All patients tolerated well dobutamine stress. In five patients G-MRI was not performed (2 because of claustrofobia, 1 because patient did not fit in MRI, 2 because of extensive ischemia by dobutamine RTMCE). A total of 41 patients underwent dobutamine RTMCE, G-MRI and QCA. The sensitivity, specificity, and accuracy to detect CAD by dobutamine RTMCE were 74%, 89% and 80% for the analysis of wall motion, 83%, 89% and 85% for the analysis of MP and 65%, 83% and 73% for dobutamine stress G-MRI. C onclusion: RTMCE seems to have better performance for detecting angiographically significant CAD than G-MRI using dobutamine stress. The analysis of MP increases sensitivity to RTMCE without changing specificity.