LONG-TERM IN-VIVO ALTERATIONS OF POLYESTER VASCULAR GRAFTS IN HUMANS

Objectives: To examine the influence of in vivo hydrolysis on the phys ical properties of polyester grafts and their correlation to the perio d of implantation in the human body. Materials and methods: Sixty-five explanted vascular grafts were obtained after 0-23 years of implantat ion due to suture aneurysms (18), occlusion (12), graft infection (12) , failure of graft material (7) and post-mortem (16). The surface was examined by scanning electron microscopy, the molecular integrity by i nfra-red spectroscopy and physical strength by probe puncture. Results : Scission of macromolecular chains and loss of strength were shown. I t was demonstrated that hydrolytic degradation of polyester takes plac e with increasing time of implantation in humans. Analysis by linear r egression showed that polyester grafts lose 31.4% of their bursting st rength in 10 years and 100% in 15-39 years after implantation. Conclus ions: Regular follow-ups of patients with aged vascular grafts and the precise documentation of implanted materials are necessary to estimat e graft degradation.