Development of an ex vivo model to investigate the effects of altered haemodynamics on human bypass grafts

The insertion of vein grafts into the arterial circulation may contribute t o vessel wall thickening and accelerated atherosclerosis, a common feature of late vein graft failure. We aimed to develop a model suitable for invest igation of the effects of altered haemodynamics on human saphenous vein fol lowing its implantation into the arterial circulation. Segments of human sa phenous vein obtained from patients undergoing coronary artery bypass surge ry were sutured at each end to PTFE and placed into flow system. Pressure a nd flowrates to stimulate the arterial and venous systems were achieved. A theoretical model of the flow chamber was created and computational fluid d ynamics software (FLOTRAN, Swanson Analysis Systems) was used to determine the flow profile within the model. In summary, a flow model has been develo ped to investigate the effect of altered haemodynamics on the molecular and pathological changes that occur in vein grafts incorpor-ated into the arte rial circulation.