Indices of effectiveness of medical and surgical treatment in 40 cases of prosthetic valve endocarditis.

Forty patients with prosthetic valve endocarditis (PVE) presenting during a 12-year period at a single hospital were studied. Twenty-six were male and 14 female and ages ranged from 19 to 67 years. During the first six post-operative months, most episodes were caused by staphylococci (38%) and Gram negative bacilli (24%). Between 6 and 11 months no episodes were seen, but thereafter streptococci predominated (50%). The overall mortality was 58% (66% during first six months; 36% thereafter). Nine of 23 patients undergoing re-operation died, most deaths occurring in patients in cardiac failure prior to surgery. Eleven deaths occurred in the 17 patients treated with antibiotics alone. Six of these were pyrexial at death and all but one was infected by a virulent organism. The remaining five were apyrexial at death and all had staphylococcal PVE. Our findings suggest: (1) all cases occurring during the first six months should be initially treated as 'early' PVE; (2) in staphylococcal PVE, apyrexia may not mean cure; (3) the principal guides to prognosis in PVE are the patient's cardiac status and the nature of the infecting organism.