Prosthetic Valve Endocarditis

In 38 cases of prosthetic valve endocarditis, 19 were early cases (onset < 60 days after insertion of prosthesis) and 19, late cases (onset> 60 days). Nine late cases had onsets 12 to 53 months after surgery. The sources or predisposing factors in late cases included dental disease or manipulation; genitourinary tract procedures; and skin, urinary, or wound infections. In contrast, most early cases were secondary to complications of operation. Streptococci were the most common organisms causing late endocarditis, whereas staphylococci were most common among early cases. Four of the six patients who survived early onset were treated with antibiotics alone; the others, with antibiotics plus reoperation. In contrast, seven of the 11 late cases that survived were treated with antibiotics alone; the other four, with antibiotics plus reoperation. The lower mortality (42% vs 68%) in the late group probably reflects the less virulent infecting organisms and the better clinical condition of the hosts. Regardless of whether prosthetic valve endocarditis occurs early or late, intensive and prolonged administration of appropriate antibiotics together with aggressive surgical reintervention in selected situations appears necessary for cure. Any patient who has a prosthetic valve and undergoes any procedure likely to produce bacteremia should receive antibiotic prophylaxis in an attempt to prevent late endocarditis.