Influence of pathogenetic factors on prognosis in patients with native valve infective endocarditis.

INTRODUCTION: Despite improvement in medical care the incidence of infective endocarditis (IE) has not decreased. Positive blood cultures are one of the most important diagnostic criteria of IE. There are no uniform data regarding the influence of pathogenetic factors on prognosis.

AIM: To analyse the results of blood and valve cultures in patients with IE of native valves and evaluate their influence on the risk of early and late deaths as well as recurrence of IE.

METHODS: The study group consisted of 152 patients with IE of native valves. The IE diagnosis was based on the Duke criteria. Early and late mortality as well as recurrence of IE were analysed in patients hospitalised at the Institute of Cardiology in Warsaw from 1988 to 1998.

RESULTS: Positive blood cultures were found in 103 (67.8%) of patients. In-hospital mortality was 5.9% (9 deaths). The incidence of early deaths was significantly lower in surgically treated patients (p=0.01). Late deaths occurred in 23 (16%) patients. Results of blood and valve tissue cultures were not related to mortality. Recurrent IE was observed in 7 (4.9%) patients. Staphylococcus aureus was an independent risk factor for recurrent IE (p=0.04). Six-year survival was 79%.

CONCLUSIONS: In patients with native valve infective endocarditis: 1. The risk of early and late death is not related to the results of blood and valve cultures. 2. Staphylococcus aureus aetiology increases the risk of disease recurrence. 3. The risk of early death is significantly lower in patients treated with surgery.