Numerical simulation of pulsatile flow in a compliant curved tube model ofa coronary artery

The endothelial cells (ECs) lining a blood vessel wall are exposed to both the wall shear stress (WSS) of blood flow and the circumferential strain (C S) of pulsing artery wall motion. These two forces and their interaction ar e believed to play a role in determining remodeling of the vessel wall and development of arterial disease (atherosclerosis). This study focused on th e WSS and CS dynamic behavior in a compliant model of a coronary artery tak ing into account the curvature of the bending artery and physiological radi al wall motion. A three-dimensional finite element model with transient flo w and moving boundaries was set up to simulate pulsatile flow with physiolo gical pressure and flow wave forms characteristic of the coronary arteries. The characteristic coronary artery curvature and flow conditions applied t o the simulation were: aspect ration (lambda) = 10, diameter variation (DV) = 6 percent, mean Reynolds number (Re) = 150, and unsteadiness parameter ( alpha) = 3. The result show that mean WSS is about 50 percent lower on the inside wall than the outside wall while WSS oscillation is stronger on the inside wall. The stress phase angle (SPA) between CS and WSS, which charact erized the dynamics of the mechanical force pattern applied to the endothel ial cell layer, shows that CS and WSS are more out of phase in the coronari es than in any other region of the circulation (-220 deg on the outside wal l, -250 deg on the inside wall). The suggests that in addition to WSS, SPA may play a role in localization of coronary atherosclerosis. [S0148-0731(00 )01201-2].