[Studies on the elastic properties of vascular prostheses].

The difference of mechanical properties between a vascular prosthesis and its host arteries is suggested to be a contributing factor in graft failure and different methods have been used to evaluate the elasticity of arterial graft. In this study, a new type ultrasonic displacement meter combined with B-mode imaging was developed and dynamic compliance of four types of arterial grafts currently available for clinical use, human saphenous vein, human umbilical vein, velour Dacron and expanded polytetrafluoroethylene (EPTFE), were measured in vitro and in vivo. Dynamic compliance was derived from intraluminal pulsatile pressure and diameter change of the vessel obtained from the displacement meter. The in vitro examination showed that the human umbilical vein was the most compliant among human saphenous vein, velour Dacron and EPTFE. The human saphenous vein was compliant in low intraluminal pressure less than 50 mmHg, and became more stiff than the human umbilical vein with increasing pressure. After experimental implantation, the compliance of human umbilical vein and EPTFE showed similar characteristics in vitro, with the exception of velour Dacron, which was progressively less compliant. In comparison of compliance of human arteries to that of arterial grafts, a mismatch in compliance between grafts and host arteries was obviously demonstrated.