Noninvasive Diagnosis of Coronary Artery Bypass Graft Disease by Dobutamine Stress Real-time Myocardial Contrast Perfusion Imaging

Background: The aim of this study was to assess the accuracy of real-time myocardial contrast perfusion imaging (MCPI) during dobutamine stress echocardiography, for the diagnosis of coronary artery bypass graft disease. Methods: MCPI was performed using commercially available ultrasound contrast agents (Optison or Definity) at rest and at peak dobutamine-atropine stress in 64 patients with previous coronary artery bypass graft. Significant disease was defined as 70% or greater stenosis in one or more grafts or a native nongrafted coronary artery. MCPI was considered diagnostic in the presence of reversible perfusion abnormalities (RPA). Results: Significant stenosis (≥70% by quantitative angiography) in one or more grafts was detected in 49 patients (77%). RPA were detected in 44 of these patients (sensitivity 90%, confidence interval [CI] 81-98). Significant stenosis was detected in 74 of the 176 bypass grafts (42%). RPA were detected in the distribution of 55 diseased grafts and 21 nondiseased grafts (regional sensitivity 74%, CI 64-84; specificity 79%, CI 71-87; and accuracy 77%, CI 71-84). RPA were detected in two or more vascular distributions in 25 of 33 patients with multivessel stenotic lesions and in 4 of 31 patients without (sensitivity 76%, CI 61-90; specificity 87%, CI 75-99; and accuracy 81%, CI 72-91). Conclusion: Dobutamine stress MCPI is a useful technique for the evaluation of coronary artery bypass graft disease.