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

Inadequate left internal mammary artery (LIMA) graft to the leftanterior descending artery (LAD) was encountered in 10 of 3,076 patientsbetween 1984 and July 1990. The mean number of bypass grafts was 2.9 perpatient. All patients with inadequate LIMA grafts were stablepreoperatively with normal to moderately reduced left ventricular function.No technical difficulties were encountered during surgery. All patientswere weaned off cardiopulmonary bypass with minimal or no inotropicsupport. Each patient developed myocardial ischemia of the LAD territoryand/or circulatory collapse or recurrent ventricular dysrhythmia during thefirst 24 h postoperatively. Six patients, who were immediately re-operatedon and had an additional saphenous graft to the LAD, recovered with noinfarction and good functional results. Four patients, who were medicallytreated, developed myocardial infarction. In cases of refractorycirculatory collapse and/or ventricular dysrhythmia, inadequate LIMA flowshould be suspected. We recommend urgent re-operation with additionalsaphenous vein graft to the LAD.