LONG-TERM GRAFT PATENCY (3 YEARS) AFTER CORONARY-ARTERY SURGERY EFFECTS OF ASPIRIN - RESULTS OF A VA COOPERATIVE STUDY

Background The long-term success of coronary bypass surgery is depende nt on graft patency after surgery. This trial was designed to determin e if aspirin improved saphenous vein graft or internal mammary artery (IMA) graft patency between 1 and 3 years after coronary artery bypass grafting (CABG). Methods and Results After receiving aspirin 325 mg/d for 1 year after CABG and undergoing a 1-year postoperative cardiac c atheterization, patients were randomized to receive either aspirin (32 5 mg) or placebo for 2 additional years. Angiography was performed 3 y ears after surgery to determine the primary end point-saphenous vein g raft patency in 288 patients and IMA graft patency in 167 patients. At 3 years after CABG, the saphenous vein graft occlusion rate was 17.0% (62 of 365) for patients treated with aspirin compared with 19.7% (74 of 376) for those who received placebo (P=.404). For saphenous vein g rafts that were patent at 1 year, the occlusion rate at 3 years was 4. 8% (15 of 313) for patients treated with aspirin compared with 4.2% (1 3 of 310) for patients who received placebo (P=.757). At 3 years, the IMA graft occlusion rate was 10.3% (8 of 78) for patients treated with aspirin compared with 7.9% (7 of 89) for patients who received placeb o (P=.594). For IMA grafts that were patent at 1 year, the occlusion r ate was 4.3% (3 of 70) for patients treated with aspirin compared with 2.5% (2 of 81) for patients who received placebo (P=.541). Conclusion s These data suggest that aspirin treatment does not improve saphenous vein graft or IMA graft patency between 1 and 3 years after CABG.