Late fiber deterioration in Dacron arterial grafts.

The occurrence of late fiber deterioration was examined in 493 Dacron arterial prostheses. Grafts implanted were of four types: 137 Meadox Wesolowski Weavenit (WN), 71 Golaski Microknit (MK), 70 USCI Sauvage(Tm) external velour non-crimped (EVNC), and 215 USCI Sauvage external velour random-crimped (EVRC). Prostheses had been implanted for three to 15.3 years; no defects were detected prior to three years. Deterioration occurred in 15 of 493 grafts (mean incidence: 3%). Between 4.9% and 5.8% of patients had graft deterioration-nearly the same incidence in all four types of grafts. Deterioration consisted of thinning and breakage of yarn filaments, causing development of holes and, in some cases, graft dilatation. Dilatation did not always precede filament breakage. Broken filament ends were either tapered or square-ended, suggesting that modes of breakage. Tensile strength tests howed that fibers sometimes weakened nonuniformly within a specimen. Fiber breakage was associated with crimp ridges. The findings suggest that manufacturing variations probably reduce fiber resistance to mechanical fatigue. Other contributing factors may include storage conditions, sterilization methods, handling, and the degradative effects of tissue fluids and enzymes.