Frequency of early occlusion and stenosis in a left internal mammary artery to left anterior descending artery bypass graft after surgery through a median sternotomy on conventional bypass: Benchmark for minimally invasive direct coronary artery bypass

Background - Uncertainty exists regarding the frequency of early occlusion when the left internal mammary artery, (LIMA) is anastomosed to the left anterior descending artery (LAD) through a sternotomy with conventional coronary artery bypass grafting (CABG). The issue has gained importance for comparison with less invasive surgical approaches in which operative exposure may be limited and graft anastomosis more difficult. Methods and Results - Data were analyzed from the International Multicenter Aprotinin Graft Patency Experience (IMAGE) trial in which 617 patients underwent conventional CABG of the LAD with a LIMA between April 1993 and May 1995. Coronary angiography was performed a mean of 10.8 days postoperatively. Patients were randomized to receive intraoperative aprotinin, an inhibitor of several serine proteinases, or placebo. Because no differences existed in patency rates of LIMA grafts between patients who received aprotinin and placebo, both groups were analyzed collectively. On coronary angiography, the LIMA was widely patent (<50% stenosis) in 561 patients (91%), had ≥50% and <99% stenosis in 48 patients (7.8%), and was occluded in 8 patients (1.3%). Therefore, the LIMA was patent in 609 patients (98.7%). Conclusions - In the IMAGE trial, the largest and most contemporary early angiographic analysis of CABG available, early patency of the LIMA was >98% when anastomosed to the LAD. These data provide an important benchmark for less invasive surgical approaches in which the LIMA is anastomosed to the LAD.