An infection-resistant PTFE vascular graft; spiral coiling of the graft with ofloxacin-bonded PTFE thread.

ABSTRACT

OBJECTIVE: To develop an infection-resistant polytetrafluoroethylene (PTFE) vascular graft for potential clinical use in grafting in sites of bacterial contamination and in replacement of the infected grafts. SETTING: Experimental study in rabbits. MATERIALS AND METHODS: An antibiotic ofloxacin (OFLX) was bonded to a sheet of PTFE by impregnation, which was cut and twisted into fine threads. The in-vitro antibacterial activity of OFLX-PTFE thread was determined by measuring the zone of growth inhibition against Escherichia coli. The thread was spirally coiled around a ridged outerwall PTFE to make the OFLX-PTFE graft. OFLX-PTFE graft or control graft was interposed in the inferior vena cava (IVC) of rabbits and the entire graft was covered with fibrin containing a fixed number of E. coli. Three or 7 days after the grafting, the grafts with perigraft tissue were harvested and subjected to bacteriological studies. RESULTS: In spite of early phase rapid elution of OFLX, a significant antibacterial activity was retained for more than 2 weeks. The antibacterial activity of OFLX-PTFE threads implanted in the subcutaneous space of rabbits decreased to 48% after 24 h and to approximately 1% after a week. The swab culture of all the control grafts was positive, while only one of 13 PTFE-OFLX grafts was positive. The number of viable bacteria in the perigraft tissue of OFLX-PTFE grafts was remarkably low in comparison with that of control grafts. Thus, the OFLX-PTFE grafts exhibited a marked in-vivo antibacterial activity. CONCLUSION: By a unique method, it was possible to furnish PTFE graft with an excellent infection-resistant property, without affecting the original biological behaviour.