Serial quantitative coronary angiography and coronary events

Background Although assessment of progression of atherosclerosis by quantit ative coronary angiography (QCA) is used as a surrogate for coronary events , no validation study has compared the several QCA measures used. Methods and Results The Cholesterol Lowering Atherosclerosis Study was a cl inico trial testing the efficacy of colestipol-niacin on the progression of coronary atherosclerosis. Baseline/2-year coronary angiograms were obtaine d on 156 men with prior coronary artery bypass graft surgery. Changes in pe rcent diameter stenosis and minimum lumen diameter (both measured in corona ry lesions and segments) and coronary segment measures of average diameter, percent involvement, and vessel edge roughness were measured by QCA. Coron ary events ascertained over 12 years of follow-up included myocardial infar ction (MI), coronary death, and coronary artery revascularizations. Proport ional hazards models evaluated the relation between QCA change measures and coronary events. Changes in percent diameter stenosis and minimum lumen di ameter of coronary artery lesions were significantly related to the risk of MJ/coronary death. All QCA measures were significantly related to the risk of any coronary event. Relative risks for each QCA measure were of similar magnitude when estimated separately within each treatment group. Change in minimum lumen diameter of lesions was the only measure independently assoc iated with the risk of coronary events. Conclusions ail oca measures of progression of coronary artery disease were related to all coronary events (including revascularizations). Only QCA me asures of lesion progression were related to MI/coronary death. QCA measure s of lesion change may be better surrogate end points for "hard" coronary e vents than measures of change in coronary segments.