Tortuosity of the superficial femoral artery and its influence on blood flow patterns and risk of atherosclerosis

The superficial femoral artery (SFA) is a typical atherosclerosis-prone site. We aimed to explore whether the tortuosity of the SFA associates with the occurrence of atherosclerosis and investigate how vascular tortuosity influences the characteristics of blood flow. Ten patients diagnosed with atherosclerotic disease in their SFAs while free of systemic atherosclerosis risk factors were enrolled together with ten atherosclerosis-free patients. The tortuosity of each SFA was quantitatively evaluated by calculating the averaged curvature (AC), maximum curvature (MC) and fraction of high curvature (FC) based on the geometrical model reconstructed from medical images. Hemodynamic studies were performed using both geometrically simplified and anatomically realistic models of the SFA to systematically address the hemodynamic effects of vascular tortuosity. Morphological analyses revealed that all curvature indices of the SFA were significantly larger in patients with atherosclerosis than in atherosclerosis-free patients (AC [mm −1 ]: 0.034 ± 0.016 vs. 0.018 ± 0.006; MC [mm −1 ]: 0.055 ± 0.023 vs. 0.034 ± 0.008; FC [%]: 22.77 ± 10.22 vs. 11.39 ± 6.82; p