Aim: The purpose of the study was the characterization of a type of rupture
occurring on warp-knitted polyester vascular prostheses.
Materials and Methods: We studied 20 cases of warp-knitted polyester vascul
ar prostheses that were explanted from humans that showed a longitudinal ru
pture as a part of a collaborative retrieval program. All the prostheses we
re immediately fixed in a 10% formaldehyde solution after their explantatio
n in the operating room. The clinical data of these cases were recorded. Th
e explants were photographed, washed to eliminate the surrounding tissues,
and photographed again. The ruptures were characterized with macroscopic ex
amination, optical stereomicroscopy, and scanning electron microscopy.
Results: The mean duration of implantation of the prostheses was 16.0 +/- 3
.3 years (range, 9-20.7 years). The prostheses were Cooley Double Velour (n
= 15) and Microvel Double Velour (n = 5). There were 16 aortobifemoral byp
ass grafts, 1 aorto-biiliac, 1 aorto-aortic, 1 iliofemoral, and 1 axillobif
emoral. The longitudinal ruptures occurred on two specific parts of the pro
stheses: the guide line (6 cases) and the remeshing line(ll cases). In thre
e cases both lines were affected. Scanning electron microscopy showed major
degradation of the trilobar filaments of the velour and gradual ruptures o
f the flat filaments of the remeshing and guide lines.
Conclusions: In this study, we have identified a specific mechanism of late
(9-20 years) longitudinal rupture of knitted polyester prostheses consisti
ng of degradation of the polyester filaments along the remeshing and guide
lines that run the length of the graft.