The internal mammary artery malperfusion syndrome: Late angiographic verification

Background. Here we report our experience with the incidence and the surgical treatment of the internal mammary artery (IMA) malperfusion syndrome, evaluate the predictive role of previously described risk factors for the syndrome, and assess the late patency of IMA grafts in patients in whom an IMA malperfusion syndrome was diagnosed and treated by additional saphenous vein grafting of the left anterior descending coronary artery. Methods. From June 1992 to November 1995, 969 IMAs were anastomosed to the left anterior descending coronary artery system. In 11 patients, IMA malperfusion syndrome was diagnosed and treated by additional saphenous vein grafting of the LAD. There were 8 men and 3 women with a mean age of 58.9 years. The angiographic and clinical data for each patient were reviewed, and all but 1 surviving patient underwent late angiographic control (mean follow-up, 18 months; range, 4 to 46 months). Results. One patient died in the hospital. No previously described risk factor was strongly associated with the occurrence of IMA malperfusion syndrome. Late angiography revealed a malfunctioning IMA graft in 7 of the 9 patients. A string sign was observed in 1 patient and a normally functioning IMA anastomosed to a diagonal branch not connected to the LAD, in another. In no patient was a widely patent and normally functioning IMA graft observed. Conclusions. In our series, a high proportion of IMA grafts were found to be malfunctioning at late angiography. This observation, in contrast to previous reports, suggests that IMA malperfusion syndrome can often be attributable to technical problems in harvesting the IMA or in performing the IMA anastomosis. Functional IMA insufficiency seems to play only a marginal role in determining the IMA malperfusion syndrome. (C) 1997 by the Society of Thoracic Surgeons.