Local hemodynamics and intimal hyperplasia at the venous side of porcine carotid artery - Jugular vein shunt

One of the chief factors, incriminated for the formation of intimal hyperplasia at the venous side of an arteriovenous shunt (AVS), is the disturbed hemodynamic condition in that region. Owing to the difficulty of properly measuring the local flow field in AVS, numerical computation has been extensively used for its assessment. The purpose of this study was to examine the flow field in AVS with computational fluid dynamics (CFD). AVS was created in a pig between the common carotid artery and the internal jugular vein using an ePTFE graft. Input data to the computational model was obtained in vivo one month later, and adjacent vessels were excised and submitted to histological examination. The 3D geometry of the shunt was determined using biplane angiography. Ultrasound measurements of the flow rates were performed with perivascular flow probes. Pressures were recorded using intravascular catheters. This data was used as boundary conditions in the commercial code FLUENTreg for calculation of the flow field. Our numerical findings are suggestive of strong Dean vortices towards both vein flow exits, verified by color Doppler. The high wall shear stresses that accompany these vortices are related to areas of intimal hyperplasia, as evidenced in preliminary histological studies of the venous vessel wall.