Background: It can be difficult to estimate the degree of stenosis in patients with diffuse coronary artery disease (CAD), because of the lack of a normal reference segment. If the size of normal coronary lumen has a direct relation to size of distal myocardial bed, it could be used to estimate the 'normal' cross-sectional area of coronary lumen. Accordingly, we could estimate the degree of stenosis of coronary arteries with diffuse disease by comparing them with calculated 'normal' areas of lumen.
Objective: To assess the validity of the above hypothesis.
Method: Fourteen subjects without coronary atherosclerosis (group A) and 16 patients with CAD (group B) underwent simultaneous bidirectional coronary arteriography. Using these coronary arteriograms, we determined the relationship between cross-sectional area of coronary lumen measured by using a computerized edge-detection system and summed distal branch length calculated by using our computerized three-dimensional reconstruction method.
Results: For group A, we found a close correlation between area of lumen and branch length (r= 0.948). However, for group B, there were some segments for which the measured area of lumen was clearly smaller than that expected from the relationship for group A. From this relationship for group A, we calculated the stenosis ratios of 22 segments and, to confirm their accuracy, we compared the stenotic ratios with those measured on intravascular ultrasound images. The stenotic ratio of each segment of stenotic coronary artery calculated by our method agreed significantly well with the results obtained from the ultrasound measurements (r= 0.980).
Conclusions: These observations validate a novel approach to quantifying diffuse CAD using clinical arteriograms.