Prosthetic valve endocarditis.

Prosthetic valve endocarditis is an infrequent but serious complication of cardiac valve replacement. The overall frequency of prosthetic valve endocarditis is approximately 2%. The frequency of early-onset and late-onset infections is 0.78% and 1.1%, respectively. Staphylococci are the most common isolate from patients with early-onset infection, accounting for 47.5% of the total number of isolates. Staphylococcus epidermidis causes 27% of these staphylococcal infections. Among patients with late-onset infection, streptococci are the predominant microorganism, constituting 42% of the total number of isolates from patients in this group. The overall mortality among patients with prosthetic valve endocarditis is high--59%; the mortality among patients with early- or late-onset infections is 77% and 46%, respectively. Most patients with staphylococcal prosthetic valve endocarditis should undergo cardiac valve replacement in addition to antimicrobial therapy. Closely monitored anticoagulant therapy should be cautiously continued in patients with prosthetic valve endocarditis.