HOSPITAL-ACQUIRED NATIVE VALVE ENDOCARDITIS - ANALYSIS OF 22 CASES PRESENTING OVER 11 YEARS

Objective-To analyse hospital acquired infective endocarditis cases wi th respect to age, sex, clinical, laboratory, and echocardiographic fe atures, predisposition, complications, surgery, mortality, and diagnos tic criteria. Design-Prospective cohort study. Setting-Teaching hospit al. Patients-A series of 200 patients with infective endocarditis pres enting over 11 years, 168 with native valve infective endocarditis, of whom 22 acquired this infection in hospital. Results-22 (14%) of the 168 cases of native valve infection were hospital acquired. The most c ommon pathogens were staphylococci (77%). Two thirds of patients had n o cardiac predisposition; one third had end stage renal disease. The m ost common source of infection was vascular access sites (73%). Eleven patients died. In 11 cases, infective endocarditis was proven patholo gically (six at necropsy, five during surgery) and analysis of these s howed that 45% were classed as probable by the Beth Israel criteria, 7 3% as definite by the Duke criteria, and 91% as definite by our sugges ted modifications of the Duke criteria. Figures for the 11 cases not p roven pathologically were 27%, 73%, and 91%, respectively. Five of the 22 cases (22%) were rejected by the Beth Israel criteria but none wer e rejected by the Duke criteria with or without our modifications. Con clusions-Hospital acquired infective endocarditis is difficult to diag nose. The Duke criteria have improved diagnostic sensitivity and our m odifications have improved it further. Mortality is high but has been reduced by surgery. This serious infection could, in many cases, be pr evented by improved care of intravascular lines and prompt removal whe n obviously infected.