Relation between tensile tests and compliance in polyester textile vascular prostheses

Background Compliance is one of the mechanical features of a vascular prosthesis (VP) that influences its performances. The goal of the present in vitro study was to attempt characterizing textile VP compliance through mechanical tests proposed in the standards. Methods Three different models of commercially available knitted VP (P1, P2, and P3) were studied using longitudinal and circumferential traction tests on coated and uncoated samples. Five samples of each model were considered for each test. The Young modulus was then calculated to indirectly predict the longitudinal and radial compliance of the VP. Moreover, actual compliance was measured on a specific device that regulates the intraluminal pressure of a fluid maintained in the tested VP at 37°C. VP dilatation under pressure load was measured with a digital camera system. Results The Young modulus variations from one VP to the other were compared with the differences between effective compliance values at radial, longitudinal, and volume level. Although the presented results show differences among the VP, one can observe that the graft materials' Young modulus and the compliance properties are linked together in general. Conclusions Although VPs are subjected to multidirectional stresses ex vivo, unidirectional standard mechanical tests, through the measurement of the materials Young modulus, can help predicting their compliance, however, in a limited frame.