Influence of Textile Structure on Longitudinal Ruptures' Localization of the Vascular Prostheses

Abstract

The prosthetic explants collection in PET knitted prosthesis enabled us to count a great number of longitudinal ruptures close to the looping wale. Previous studies showed modifications of the polymer organization after a stay in the human body. To supplement these studies, we undertook circumferential traction tests, which partly simulated the action of a pressure in the prosthesis. As the localization of a rupture is often caused by a localization of the constraints, we used a video camera to make films of the knitting structure in order to highlight the behavior of a mechanical heterogeneity. This device also allowed us to define a global coefficient related to the deformability of the textile structure. The overall results showed that for similar prostheses, a structural heterogeneity existed. It then generated various behaviors which were constraint sources and thus of ruptures by mechanical fatigue. Therefore, our approach highlighted the possibility of an early study of the rupture zones' localization. For that study, the investigation methods require improvement. However, the heterogeneity of the mechanical behavior was not able to explain the entire ageing phenomenon. For example, the guide-line ruptures are not yet well understood.

Long-Term Biostability of Pet Vascular Prostheses

“…Ruptures of polyester textile prostheses have been rarely reported in the literature. In a previous study [3,15,24] as a part of a European collaborative program, we collected 20 cases of ruptures occurring on two similar prostheses constructed by the same manufacturer. We demonstrated that these ruptures were not randomly distributed on the textile structure of these warp-knitted prostheses but that they occurred on two well-defined areas: the remeshing line and the guide line.…”

“…The mechanisms of degradation are not yet clearly understood but are probably multifactorial. Degradation may be related to a preexisting weakness of the prosthesis prior to implantation, such as a poor design of the textile structure or alterations of the prosthesis during its manufacturing process [14,15]. Currently, warp-knit structures have demonstrated a good long-term stability and are widely implanted.…”

Fatigue behaviour of biocomposites

“…These concerns led to several efforts to improve preclinical testing. Alternatively, cyclic mechanical testing can be performed by a circumferential tensile test, in which two metal halfcylinders are introduced into the prosthetic tube and moved apart (Dieval et al, 2008). Publication of the standard in 2003 succeeded in standardizing testing and reporting across device manufacturers; however, several clinical failure modes, such as migration and fractures, continued to be unpredicted by current preclinical testing.…”

Development of a test bench assessing the hydrodynamic compliance of vascular prostheses

“…Dilation, aneurysmal failure, structural defects, interstitial bleeding and infection are among the most reported complications affecting medium and large caliber (more than 8 mm diameter) polyethylene terephthalate (PET) prostheses. [1][2][3][4][5] The dilation, the most cited complication, is characterized by a remnant expansion of the prosthesis diameter under the cumulative effect of blood pressure. Due to the mechanical mismatch between graft and host artery, early dilation generally occurs during the few weeks following implantation: circumferential expansions close to 10% for woven prostheses and 20% for knitted ones have been thus recorded.…”