Progression of atherosclerotic lesions in grafts and native vessels lead to recurrent angina, unaltered long-term survival and reduced efficacy of repeat CABG surgery. Johnson in an 11 year follow-up of 3,105 post-CABG patients, reported that about 15 percent of patients with preoperative angina have recurrent angina at 1 year; with a further 6 percent developing angina every subsequent year. In this study, patients with recurrent angina had twice the mortality compared to those who were angina-free. Long-term follow-up of the VA Cooperative Trial of CABG shows that the survival of the surgical group appears to be initially superior compared to the medical group but this benefit is diminished by about ten years. This may relate to graft obstruction and progression of native coronary atherosclerosis. Re-operation in these patients carries a higher operative mortality risk and the results are less impressive. It had been estimated that approximately 5 percent of all CABG surgery in 1984 were re-operations and that this percentage would double over the next decade. Therefore, measures to prevent graft occlusion and progression of atherosclerosis in native vessels, if successful, could have substantial clinical and economic importance by reducing mortality, morbidity and the numbers of patients undergoing re-operations.