Grading of coronary atherosclerosis Comparison of a modified IAP visual grading method and a new quantitative angiographic technique

We submit a quantitative method for measuring atherosclerosis from angiograms of autopsied hearts. Casts were made of the coronary vessels of human excised hearts by filling coronary arteries with rapid polymerizing radiopaque silicone rubber. Angiograms of the casts resembled clinical arteriograms. Corresponding segments were marked off on angiograms, and the arterial intimal surface and the arteries graded visually by four graders four times. Vessel edges on the angiograms were located by a film digitizer coupled to a computer. Estimates of atherosclerosis were derived from deviations in the smoothness of the edge. Correlation with pooled visual grades was 0.56, P < 0.001. Computer grading was significantly more reproducible. The standard deviation among graders was 19.5 (coefficient of variation 45 %); between computer runs 0.10 (coefficient of variation 1.17%).