Molecular weight characterization of virgin and explanted polyester arterial prostheses.
The macromolecular properties of 17 virgin commercial arterial prostheses and a series of explanted prostheses, both manufactured from poly(ethylene terephthalate) (PET) yarns, have been studied by gel permeation chromatography (GPC) and by differential scanning calorimetry (DSC). Only small differences were found between the average molecular weights and the degree of crystallinity of the unused reference grafts. A broadening of the DSC curves was observed for the prostheses containing texturized yarns compared with those made solely from flat, untexturized yarns. This broadening may be due to greater heterogeneity of the crystal sizes caused by the texturizing process and to the use of two or more different yarns with dissimilar thermal histories in the same prosthesis. Average molecular weights of the explant series were significantly lower than those of the corresponding reference grafts but almost time independent. The polydispersity index and the degree of crystallinity of the explants remained constant as a function of time. These results are discussed in regard to others available in the literature.
[Aneurysm formation on dacron prosthesis after 84 months of use. Pathology, structural and chemical evaluation of the explanted device (author's transl)].
A 56 year old patient fitted with a femoro-popliteal Dacron prosthesis (Weavenit-Meadox Medical) 84 months earlier, presented with a severe palpable dilation in the middle part of the graft. The dilated segment of the prosthesis was resected locally and spliced to a new fabric device. The explanted section of prosthesis was analyzed; the dilation was found to extend only over several centimeters near the centre of the prosthesis. The degree of "healing" was found to be satisfactory except in the part which was most distended; this area also revealed mild bacterial colonization. Physico-chemical analysis of the fabric revealed that the dilation had taken place subsequently to hydrolytic degradation of the polyester fibres. Manufacturing conditions may have contributed to predisposing parts of the prosthesis to accelerated biodeterioration in vivo.
Failure of ultralightweight knitted Dacron grafts in arterial reconstruction.
We have observed 11 cases in which the use of the ultralightweight knitted Dacron arterial graft made by the United States Catheter and Instrument Co. (USCI) was complicated by Interstitial hemorrhage dilation, or both. Although the incidence and specific cause of failure of this graft are unknown, we have discontinued its use on the basis of this experience.