Background: Previous studies have suggested that angiographic evidence of disease progression in coronary arteries increases the risk of subsequent coronary clinical events. This study ascertained whether patients enrolled in the Post Coronary Artery Bypass Graft Clinical Trial (POST CABG) who had substantial progression of atherosclerosis in >or=1 saphenous vein grafts (on the basis of assessment of baseline and follow-up angiograms obtained 4-5 years after study entry), but who had not reported clinical symptoms before follow-up angiography, were at a higher risk of subsequent events than patients who did not have substantial progression of atherosclerosis (decrease >or=0.6 mm in lumen diameter at site of greatest change from baseline).
Methods: All 1351 patients enrolled in the trial underwent baseline angiography; only the 961 patients who had follow-up angiography and no coronary events before the follow-up study were included in this analysis. The clinical center staff contacted patients to ascertain the events that had occurred after follow-up angiography (approximately 3.4 years later).
Results: Sixty-nine patients had died; 870 patients or relatives were interviewed, and 22 patients could not be contacted. Univariable estimates of relative risk associated with substantial progression ranged from 2.2 (P <.001) for cardiovascular death or nonfatal myocardial infarction to 3.3 (P <.001) for revascularization. Multivariable and univariable estimates of risk were similar.
Conclusions: The findings provide evidence that patients who had substantial progression of atherosclerosis in vein grafts are at an increased risk for subsequent coronary events and suggest that angiographic changes in vein grafts are appropriate surrogate measures for clinical outcomes.