Commentary

For several decades it has been shown that areas of formation of atherosclerotic lesion have been associated with areas of low shear stress. Elegant experiments have shown this in the carotid bifurcations and iliac arteries. This article uses 5 isolated arterial trees from humans postmortem with sufficient length of the carotid siphon and showing the ICA and MCA branches. The velocity profiles throughout the bifurcations are examined and nicely illustrated in the author's figures. Their conclusions are that areas of low shear stress support the development of atherosclerotic lesions almost exclusively along the inner wall of the curved segments and outer wall of one or both daughter vessels at major bifurcations. The article also points out that the incidence of aneurysm formation is related to the magnitude of the approaching velocity of blood at bifurcations and especially at sharp bends where these aneurysms can form. These conclusions are well accepted in mathematical models but are nicely illustrated in this article with flow visualization and high-speed cinemicrographic techniques.