Isobaric elastic mismatch among native arteries and conduits used in systemic vascular by-pass

An arterial bypass might be either carried out with a venous segment or using a polytetrafluoroethylene (ePTFE) graft. Different patency rates were reported depending on the chosen method. Our objective was to compare the elastic properties of three different segment: A) expanded synthetic polytetrafluoroethylene (ePTFE) grafts, B) jugular veins, and C) systemic arteries (femoral artery). Pressure (P) and diameter signals were measured in six ovine venous, arterial, and ePTFE segments, mounted in a circulation mock and perfused at systemic pressure and stretch rate. Elastic modulus (E_inc) was calculated at 100 mmHg using a pressure and diameter analysis. At systemic P level, both venous and ePTFE were suffer than the artery (p<0.05), but venous E_inc was more compliant than the ePTFE (p<0.05). The elastic mismatch was higher (p<0.05) between a ePTFE graft and the artery than between the vein and the artery. This could explain the major incidence of arterial by-pass failure reported when a ePTFE graft is chosen.