994-99 Can Late Saphenous Vein Graft Closure Be Predicted by Quantitative Angiographic Analysis Before the Clinical Event?

Angiographic parameters predicting the likelihood of late occlusion of saphenous vein grafts (SVG) have been infrequently described. The Post-CABG Study, a 5-year trial aimed at reducing SVG closure in minimally symptomatic patients 1–11 years Post-CABG, offers a unique view into this event since this study requires an angiogram to document baseline graft patency. In this preliminary study we performed quantitative angiographic analysis (QAA Reiber) comparing the baseline Post-CABG study angiogram to an unscheduled “clinically driven” angiogram. Of 1253 enrolled patients with at least one patent SVG, 35 developed MI or unstable angina associated angiographically with a changed SVG lesion and either total or subtotal occlusion. Average patient age was 58±2 (SEM)years; 97% were male. Years since SVG placement to baseline angiogram averaged 6.5±0.4 (range 2–14). Time from the baseline to the unscheduled angiogram was 22±2 mo (range 3–47). In 28 patients the involved graft was single and in 7 sequential. The SVG insertion segments involved the LCX in 17, RCA in 15 and LAD in 10.ResultsThe initial lesion diameter at the site of the subsequent inciting lesion for all 35 patients averaged 2.58±0.17 mm, or 29.5±3.6% diam. stenosis. (This was defined as the most severe stenosis in any part of the graft in patients with subsequent total graft occlusion, and the exactly matched graft site in those with subtotal occlusion.) In 8 patients the baseline SVG was entirely normal. The initial lesion was >50% stenosis in only 4 patients. At the time of the clinical event, the lesion had progressed to 87±2.6% diam stenosis (N=35). In 16 patients the causal lesion was subtotal, while in 19 the SVG was totally occluded. The mean native vessel — responsible graft anastomotic diameter was 2.33±0.12mm.ConclusionQAA of SVG in asymptomatic patients may not predict subsequent graft closure associated with acute coronary syndromes. The initial site of the lesion is typically of mild-moderate severity, and only later exhibits rapid progression to occlusion