Single versus bilateral internal mammary artery for isolated first myocardial revascularization in multivessel disease: long-term clinical results in medically treated diabetic patients.

BACKGROUND: We evaluated our experience to investigate if the use of bilateral internal mammary artery (BIMA) grafting, with or without complementary saphenous vein grafts (SVG), increases the quality of the results of coronary bypass grafting in medically treated diabetic patients who undergo first myocardial revascularization, when compared with the use of a single left internal mammary artery (LIMA) and SVG.

METHODS: From October 1991 to December 2001, 558 diabetic patients with multivessel coronary disease had first isolated myocardial revascularization using LIMA and SVG (group LIMA) in 217 cases and BIMA +/- SVG (group BIMA) in 341. Propensity score analysis identified 400 patients, 200 for each group, with similar preoperative characteristics. Thirty-day outcome and 8-year freedom from death from any cause, cardiac death, acute myocardial infarction (AMI), AMI in a grafted area, redo/percutaneous transluminal coronary angioplasty (PTCA), redo/PTCA in a grafted area, target cardiac events, and any event were evaluated. Follow-up ranged from 2.0 to 12.2 years (mean 6.0 +/- 2.0).

RESULTS: There was no difference between groups except the cardiac deaths, which were significantly higher in the LIMA group (7 versus 0, p = 0.015). The BIMA group showed better 8-year freedom from death any cause (86.7 +/- 3.2 versus 79.5 +/- 4.1, p = 0.0274), cardiac death (96.3 +/- 1.4 versus 88.4 +/- 4.0, p = 0.0406), acute myocardial infarction (99.5 +/- 0.5 versus 92.0 +/- 3.9, p = 0.0092), and acute myocardial infarction in a grafted area (99.5 +/- 0.5 versus 93.4 +/- 3.7, p = 0.0204). Cox analysis confirmed that the use of LIMA and SVG was an independent predictor for lower freedom from death (hazard ratio [HR] = 1.8, p = 0.0310), cardiac death (HR = 1.9, p = 0.0426), AMI (HR = 9.7, p = 0.0033) and AMI in a grafted area (HR = 8.2, p = 0.0410).

CONCLUSIONS: In diabetic patients with multivessel disease who undergo first myocardial revascularization, BIMA +/- SVG provides higher freedom from death, any cause, and cardiac-related death, if compared with LIMA + SVG. It plays a protective role in reducing the incidence of late AMI.