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.
The degradation of polyethylene terephthalate by methylamine—A study by infra-red and X-ray methods
Abstract The physical changes taking place during the degradation of polyethylene terephthalate with aqueous methylamine at room temperature have been followed by chemical, X-ray and infra-red methods and it is concluded that although there is a rapid initial degradation of the amorphous regions, extensive degradation leads to attack of both crystalline and amorphous regions.
Failure of Dacron Arterial Prostheses
The report by Cooke et al (see page 101) of three failures of synthetic replacements in the abdominal aorta serves to remind us that when using manufactured devices for human spare parts, one must commit himself to a follow-up of such a patient for his remaining life. Not only is important information obtained regarding the performance of the particular prosthesis, but additional data are provided about the natural history of the atherosclerotic process and about the late complications deriving from this aging process. We began our evaluation of synthetic materials used for biological purposes shortly after the notable report in 1951 by Voorhees and associates which established the capability of such materials for arterial replacement. Within a very few years, it became evident that virtually every established vascular surgeon was utilizing a variety of synthetic materials for this purpose, derived from an equal variety of sources—ranging from sophisticated textile manufacturing