Which of the following statements about patients treated by placement of an internal mammary artery (IMA) bypass graft at primary CABG is/are correct?

B. Left ventricular function is better preserved at the time of reoperation.

 D. A light clamp should be applied to the IMA pedicle to limit cardiac warming during cardioplegic arrest at the time of reoperation.

E. A functional study demonstrating a large portion of myocardium at risk should be obtained before reoperation.

DISCUSSION: Patients who have an intact IMA graft should have severe anginal symptoms and a significant portion of myocardium at risk before reoperative coronary bypass grafting is considered. A functional study may better define the proportion of myocardium at risk for ischemia and infarction. Patients with an intact IMA graft are less likely to require reoperation, but if stenosis distal to the IMA and disease in other vein grafts have progressed or if a large portion of myocardium is at risk, reoperation is recommended. The presence of an intact IMA is not a contraindication to reoperation; in fact, this population of patients have better-preserved ventricular function and are, perhaps, better candidates for reoperation. Placement of an IMA graft at the time of the first operation was critically important, neutralizing the adverse effects of elevated serum cholesterol, hypertension, and smoking on reoperation-free survival. The risk of damaging an intact IMA graft is 3% to 5%. A lateral projection of the IMA at cardiac catheterization will define its course, particularly in relation to the sternum, to allow more careful sternal re-entry. The IMA should be minimally dissected and a light clamp applied during cardioplegic arrest to limit cardiac warming and improve myocardial protection. The IMA may be detached and recycled if needed. The use during reoperation of the contralateral IMA does not increase the risk of sternal wound complications.