Long-term in vivo alterations of polyester vascular grafts in humans

Objectives: To examine the influence of in vivo hydrolysis on the physical properties of polyester grafts and their correlation to the period of implantation in the human body. Materials and methods: Sixty-five explanted vascular grafts were obtained after 0-23 years of implantation 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 infra-red spectroscopy and physical strength by probe puncture. Results: Scission of macromolecular chains and loss of strength were shown. It was demonstrated that hydrolytic degradation of polyester takes place with increasing time of implantation in humans. Analysis by linear regression showed that polyester grafts lose 31.4% of their bursting strength in 10 years and 100% in 25-39 years after implantation. Conclusions: Regular follow-ups of patients with aged vascular grafts and the precise documentation of implanted materials are necessary to estimate graft degradation.