Echocardiography in Minimally Invasive Direct Coronary Artery Bypass

Minimally invasive direct coronary artery bypass (MIDCAB) is a recently developed, less-invasive alternative to standard bypass surgery. MIDCAB is performed through a small incision (2-3 inches) on the beating heart without the use of cardiopulmonary bypass or cardioplegia. It is associated with less trauma and a shorter hospital stay than conventional surgery. Transesophageal echocardiography helps in patient selection by detecting protruding aortic atheromas (PATHs), which are associated with a high risk of stroke during typical cardiopulmonary bypass. MIDCAB may be the technique of choice in patients with PATHs. Intraoperative echocardiography can detect wall motion abnormalities and helps in determining intraoperative myocardial ischemia and the postoperative prognosis. Duplex study of the internal mammary arteries is helpful in evaluating coronary anastomosis patency. Characteristically, a patent coronary anastomosis demonstrates a high diastolic flow fraction, with a ratio between peak diastolic and peak systolic flow velocity of > 1.