Impregnation of sewing ring with antibiotics to avoid prosthetic valve endocarditis

Abstract

We read with great interest the original article by French and associates1French BG Wilson K Wong M Smith S O'Brien MF Rifampicin antibiotic impregnation of the St. Jude Medical mechanical valve sewing ring: a weapon against endocarditis.J Thorac Cardiovasc Surg. 1996; 112: 248-252Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar regarding rifampicin impregnation of a mechanical valve sewing ring to prevent early endocarditis. Prosthetic valve endocarditis (PVE) is still a dangerous complication of cardiac operations. The reported incidence in the literature ranges from 1% to 9% in patients undergoing heart valve replacement. Direct contamination during the operation has been suggested as a possible cause of early and late postoperative PVE. Systemic antibiotic prophylaxis fails to achieve a sufficient antibiotic concentration in the sewing ring of the prosthesis, where PVE usually develops. Another study by Karck and colleagues2Karck M Siclari F Wahlig H Sperling U Schmid C Haverich A Pretreatment of prosthetic valve sewing ring with the antibiotic fibrin sealant compound as a prophylactic tool against prosthetic valve endocarditis.Eur J Cardiothorac Surg. 1990; 4: 142-146Crossref PubMed Scopus (22) Google Scholar showed a significant increase in the antibiotic concentration in the sewing ring after prosthetic valve pretreatment with a fibrin sealant compound. In 1971 we began pretreating prosthetic valves by immersing them in antibiotic solution before implanting them in patients. From 1971 to December 1991, 1262 patients (504 men and 758 women, mean age 42.3 years, standard deviation 11.1; range 20 to 71 years) underwent heart valve replacement at our institution.3Actis Dato Jr, A Chiusolo C Cicchitti GC Actis Dato GM Porro MC Bello A Pretrattamento antibiotico delle protesi valvolari.Minerva Cardioangiol. 1992; 40: 225-229PubMed Google Scholar Most of the patients (1250/1262; 99%) had elective operations. All patients but two received mechanical valves. A variety of systemic antibiotics were used for prophylaxis through the years at induction of anesthesia (penicillin, kanamycin, oxacillin, ampicillin, piperacillin, and ceftazidime). Before the prosthesis was lowered, the sewing ring was immersed in 50 ml of saline solution containing the same antibiotic used at induction. The sewing ring was generally soaked completely within 2 to 3 minutes. Parenteral antibiotic administration was maintained during the following 4 postoperative days. A complete follow-up was obtained in 964 patients (76.4%) by means of examination, questionnaires sent to their cardiologists, or telephone contact. The incidence of early PVE was only one case (0.08%) 2 months after valve implantation, resulting from Staphylococcus epidermidis, and the patient underwent a successful second operation. Late PVE was observed in 12 cases (0.95%; Streptococcus, n = 5; Gram negative Haemophilus and Brucella, n = 2; Candida, n = 1; indeterminate, n = 4). Seven patients were medically treated, none of whom died, but five underwent a second operation with two operative deaths (15%). In this large series of heart valve replacements the low incidence of early PVE can be attributed partially to the small number of emergency operations (1% only), but we believe that soaking the valve in antibiotic solution before implantation was helpful as well. Early PVE is almost always related to direct contamination during the operative procedure or to native valve endocarditis. The prosthesis sewing ring is usually the site of implantation of the etiologic agent because the low blood flow at the interface between the prosthesis and the valve anulus prevents adequate contact with the antibiotic present in the serum. We believe that increasing the concentration of antibiotics in the valve sewing ring or vascular prosthesis is the correct philosophy to decrease this complication after heart valve implantation, and we congratulate French and colleagues for their idea to increase the concentration of antibiotics in the prosthetic tissue.