Geometrical risk factors for atherosclerosis in the femoral artery: a longitudinal angiographic study.

Abstract

In order to study the evolution of atherosclerosis in the superficial femoral artery in relation to local factors of vascular geometry, image processing of digitized angiograms was carried out in 237 hyperlipidemic patients before and after a three-year period of lipid-lowering treatment. The degree of atherosclerosis was measured as edge roughness, which was calculated separately for inner curves, outer curves, and straight segments and, in a subgroup of 110 patients, for segments with and without branches on either side of the artery. Initially, inner curves had significantly higher roughness values than outer curves, and outer curves higher than straight segments. After three years, there was an increase of borderline significance in the outer curves, and the difference between inner and outer curves was no longer significant. In several subpopulations, the increase in outer curve roughness was clearly significant. When branched and nonbranched segments were compared, the only significant difference was at the second examination where segments with a lateral branch had higher roughness of the medial edge than those without such a branch. It is concluded that curves are more likely than bifurcations to constitute a geometric risk factor for atherosclerosis, but it remains to explain the causal mechanism for this factor.