On matching compliance between canine carotid arteries and polyurethane grafts.
Compliance mismatch between a host artery and an implanted graft has been suggested as a contributing factor to a small diameter graft failure. In this study, static compliance and dynamic compliance were defined and measured in vitro and in vivo for canine carotid arteries and 2 types of polyurethane grafts. Based on these compliance values, the circumferential modulus (E[theta]) and longitudinal modulus (Ez) were calculated. It was shown that grafts have constant moduli over a wide range of pressure while the moduli of carotid arteries increase significantly with increasing pressure (dynamic E[theta] from 0.20 to 1.32 MPa). Polyurethane grafts are nearly isotropic, with the modulus almost identical in each direction, while carotid arteries are anisotropic (E[theta]/Ez = 2-3). The dynamic moduli are generally higher than static values and are especially pronounced for arteries. Due to these different inherent characteristics, the compliance of a synthetic graft may match that of the host artery only in the circumferential direction and within a small pressure range. A stated limitation is therefore given for complete compliance matching. The results provide a rationale for identifying the degree of compliance match. These efforts may lead to better designed vascular grafts.
Hsu
S
S
Department of Chemical Engineering, Chung Hsing National University, Taichung, Taiwan, ROC.
Kambic
H
H
D000818:Animals; D001672:Biocompatible Materials; D001696:Biomechanical Phenomena; D001807:Blood Vessel Prosthesis; D002339:Carotid Arteries / Q000502:physiology*; D003187:Compliance; D004285:Dogs; D066298:In Vitro Techniques; D008954:Models, Biological; D011140:Polyurethanes; D011475:Prosthesis Failure
D001672:Biocompatible Materials; D011140:Polyurethanes