Prosthetic valve endocarditis. Experience with porcine bioprostheses

Prosthetic valve endocarditis remains an infrequent but serious complication of cardiac valvular replacement. Prosthetic valve endocarditis was diagnosed in 56 (1.8%) of 3200 patients in whom one or more porcine bioprostheses were implanted between 1975 and 1988. Of the 56 patients with prosthetic valve endocarditis, there were 40 men and 16 women, with a mean age at initial implantation of 57 years (27 to 81 years). Of the 56 patients, 6 were initially treated for native valve endocarditis. There were 8 cases of early prosthetic valve endocarditis (defined as occurring less than 60 days after initial surgical intervention) and 48 cases of late prosthetic valve endocarditis (occurring after 60 days). The overall mortality rate of the 56 patients was 32% (18 patients). Of the 8 patients with early prosthetic valve endocarditis, 6 (75%) died. Of the 48 patients with late prosthetic valve endocarditis, 12 (25%) died. The predominant organisms were Staphylococcus epidermidis (12 cases), Streptococcus viridans (8 cases) and Staphylococcus aureus (7 cases). The presence of hemodynamic compromise, including congestive heart failure, septic embolism, persistent sepsis, and echocardiographic evidence of vegetations, dictated the mode and timing of the addition of surgical intervention to medical therapy. The survival rate for medically and surgically treated patients with late prosthetic valve endocarditis was 91% (20 patients); none of the patients with early prosthetic valve endocarditis survived (all had severe hemodynamic compromise). We analyzed 18 factors for the prediction of early and late death. The predictors of death by univariate analysis for both early and late prosthetic valve endocarditis were age, diagnosis time, renal status, sepsis, management mode, fever, dental procedures, and dental prophylaxis. The predictors by multivariate analysis were age, diagnosis time, renal status, and management mode for early prosthetic valve endocarditis, and only diagnosis time for late prosthetic valve endocarditis. Annular abscess formation occurred in 27% of the patients. There were no complex aortic or mitral reconstructions. There was one reoperation for recurrent and residual endocarditis. There was one late death as a result of recurrent prosthetic valve endocarditis. We advocate early diagnosis and aggressive combined medical and surgical treatment before the development of hemodynamic compromise and other characteristic signs when the culprit organisms are Staphylococcus aureus, gram-negative organisms, and Candida albicans.