Changes following in vitro endothelial cell lining of ePTFE prostheses: late morphologic evaluation of six failed grafts.

This paper describes the morphologic appearance during long term follow-up of in vitro endothelialised ePTFE grafts (IVECL) implanted in patients with crural reocclusions. Between June 1989 and December 1990, 13 femorocrural IVECL bypasses were implanted. Follow-up angiograms demonstrated stenoses in the middle of the graft in six patients. Two of these patients developed symptoms, and the grafts were biopsied approximately 1.5 years after implantation during a patchplasty procedure. The remaining four patients with asymptomatic stenoses refused elective reoperation and suffered a graft occlusion 53 to 619 days after implantation, all leading to amputation. Biopsy specimens and explanted grafts were examined with standard and electron microscopy. Both biopsies demonstrated multiple layers of degenerating myofibroblasts (MFB). The four explanted grafts also showed altered MFB in addition to necrosis of the graft surface. No endothelial cells were seen on any of the preparations. Long term follow up of IVECL protheses in the crural position has demonstrated that it is possible to lastingly bind cells on an artificial surface. Whether the MFB found are a substitute of lost endothelial cells, or are an end product of metaplastic and/or degenerative alterations, can only be clarified through further biopsy studies.