Local hemodynamics and wall shear stress (WSS) impact healing of implanted expanded polytetrafluoroethylene (ePTFE) vascular grafts. Since adverse outcomes occur shortly after implantation, we documented the effect of local hemodynamics on short-term healing. We implanted a control or a stenotic ePTFE graft with a 60 μm internodal porosity into the abdominal aorta of 15–20 kg juvenile male baboons. At one month we harvested all grafts using in situ pressure perfusion. We interrogated the local hemodynamics with aid of computational fluid dynamics. We constructed three different geometric grids of the vascular grafts. We defined the first grid based on the material specifications of the graft material. We constructed the second grid by outlining the contours of the graft from the sectioned and stained histologic slides. Lastly, we created the third grid by capturing the graft contours from axial sections of the in vivo grafts acquired with a 1.5 T Phillips® MRI. Using volumetric flow rate and PC-MRI data, we performed steady state and pulsatile simulations. We then correlated the calculated wall shear stress and the measured pseudointima formation. The results demonstrated that high wall shear stress fails to inhibit intimal thickening during short term graft healing.

This content is only available via PDF.
You do not currently have access to this content.