Internal Mammary Artery Revascularization: Fact or Fantasy?

Late hemodynamic evaluation, including ventricular function studies, has been made on 37 patients one to three years following bilateral internal mammary artery implantation. Of these patients, 31 percent also had excision of aneurysms or akinetic areas of chronic fibrosis. Cineangiographic volume flow studies demonstrated the incidence of, and volume flow through perfusing implants. Ninety-four percent of those evaluated had evidence of supplemental flow. However, only 61 percent of the patients demonstrated coronary artery opacification and 66 percent showed areas of myocardial blush during injection of the internal mammary arteries. Only 54 (73 percent) of the 74 implanted internal mammary arteries showed evidence of myocardial perfusion, but when considered in relation to the 60 coronary arteries which were 90-100 percent occluded in these 37 patients, the incidence of functioning implants increased to 90 percent when properly employed. Flow studies were correlated with ventricular function. The majority had improvement in cardiac output and stroke volume, but no significant change in left ventricular end-diastolic pressure. The precise indications for the use of internal mammary artery implantation in order to obtain functioning implants and the limitations inherent in their use are stressed.