Inadequate internal mammary artery graft as a cause of postoperative ischemia: incidence, diagnosis and management.

Inadequate left internal mammary artery (LIMA) graft to the left anterior descending artery (LAD) was encountered in 10 of 3,076 patients between 1984 and July 1990. The mean number of bypass grafts was 2.9 per patient. All patients with inadequate LIMA grafts were stable preoperatively with normal to moderately reduced left ventricular function. No technical difficulties were encountered during surgery. All patients were weaned off cardiopulmonary bypass with minimal or no inotropic support. Each patient developed myocardial ischemia of the LAD territory and/or circulatory collapse or recurrent ventricular dysrhythmia during the first 24 h postoperatively. Six patients, who were immediately re-operated on and had an additional saphenous graft to the LAD, recovered with no infarction and good functional results. Four patients, who were medically treated, developed myocardial infarction. In cases of refractory circulatory collapse and/or ventricular dysrhythmia, inadequate LIMA flow should be suspected. We recommend urgent re-operation with additional saphenous vein graft to the LAD.