A 10-year retrospective study of infective endocarditis at a university hospital with special regard to the timing of surgical evaluation in S. viridans endocarditis.

A total of 154 episodes of infective endocarditis (IE) in 149 patients were studied retrospectively with special regard to the major aetiological groups and the surgical evaluation. There were 136 episodes of native valve endocarditis (NVE) (88%) and 18 episodes of prosthetic valve endocarditis (PVE) (12%). Three major groups of NVE crystallized: Streptococcus viridans in 37 (27%), Staphylococcus aureus in 39 (29%) and culture negative IE in 28 (21%) episodes. In these groups surgery during the active phase was required in 41, 28 and 18%, respectively. At the operation myocardial abscess was found in as many as 7/15 cases with S. viridans, but in only in 3/11 cases with S. aureus and 1/5 cases with culture negative IE. The mean duration of preoperative antibiotic treatment was 34 d. This long period of unsuccessful pharmacotherapy, preceded by a mean of 47 d from start of symptoms to admission to hospital, has probably resulted in the high frequency of myocardial abscess in S. viridans NVE. Surgical evaluation should be considered when fever persists beyond 10 d of adequate treatment, even in the absence of clinically apparent complications. Among the PVE episodes, 11/18 were managed with pharmacological treatment alone. Uncomplicated PVE may thus often be successfully treated with antibiotics alone.