Geometric risk factors for atherosclerosis in the aortic bifurcation: a digitized angiography study.

To clarify the relationship between arterial geometry and atherosclerosis at the aortic bifurcation, angiograms of 84 patients with slight or moderate atherosclerosis were studied by computerized image analysis. The degree of atherosclerosis involvement was assessed as angiographic edge roughness. The branching angles were found to be related to edge roughness of the left outer wall and the right side of the aorta. The position of the flow divider was related to edge roughness of the medial wall of the right common iliac and the right side of the aorta. For these two locations, there were also significant relationships to the area ratio, i.e., the ratio between cross-sectional areas distal and proximal to the bifurcations. On the basis of these findings, the concept of "geometric risk factors" for atherosclerosis and the potential influence of blood flow on atherogenesis are discussed.