RIFAMPICIN ANTIBIOTIC IMPREGNATION OF THE ST-JUDE MEDICAL MECHANICAL VALVE SEWING RING - A WEAPON AGAINST ENDOCARDITIS

The Dacron sewing ring material of the St, Jude Medical mechanical hea rt valve (St, Jude Medical, Inc., St, Paul, Minn.) was passively impre gnated with rifampicin (60 mg/ml) both in its unsealed state and after sealing by the methods of preclotting in blood, autoclaving in blood, and autoclaving in 20% albumin. Antistaphylococcal activity in the Da cron material was assessed immediately after rifampicin impregnation a nd at regular periods up to 5 days after implantation into the goat ao rta, When the Dacron material had been sealed by autoclaving in blood and autoclaving in 20% albumin significant retention of antistaphyloco ccal activity was found after 5 days in vivo, Best results were obtain ed with the use of autoclaved blood (p < 0.05), We also compared these results with those obtained from impregnating commercially available gelatin sealed (Gelseal) and collagen-sealed (Hemashield) Dacron mater ial with rifampicin, Although anti-staphylococcal activity was equival ent immediately after rifampicin impregnation, after 4 days in vivo th e activity was negligible in Gelseal material (p < 0.05) and could not be demonstrated in Hemashield material, Rifampicin impregnation of th e intact St, Jude Medical mechanical valve sewing ring may have an app lication in the prevention of prosthetic valve endocarditis and a clin ical protocol is suggested.