Sometimes, patients scheduled for cardiac operations other than coronary artery bypass may be unsuitable for preoperative coronary angiography. We routinely use intraoperative high-resolution epicardial ultrasound to select the proper target for the graft and to check graft anastomosis integrity. We describe 3 patients who could not undergo preoperative coronary angiography for different reasons. In all cases, we discovered significant stenosis in the left anterior descending coronary artery, which required bypass grafting. Intraoperative verification by transit-time flow measurements confirmed the significant stenosis detected by imaging.