Aims: To evaluate the diagnostic usefulness of serial serum C-reactive protein determinations in monitoring the outcome of infective endocarditis (IE).
Methods and results: C-reactive protein, erythrocyte sedimentation rate (ESR), and white blood cell count (WBC) were measured from admission until week 10 in 129 patients with 134 episodes of IE. Need for cardiac surgery and final outcome were assessed until 3 months from admission. Data were evaluated using extensive statistical analyses. The fall in serum C-reactive protein or WBC was significantly faster when a patient had an uncomplicated recovery than when complications developed or death ensued, but no such behaviour was observed in ESR. None of the 80 patients who had normal C-reactive protein by week 10 died of IE. Moreover, none of the 22 patients who had normal C-reactive protein by week 4 needed cardiac surgery and only two of the 33 patients who had normal C-reactive protein by week 6 needed cardiac surgery, both after successful medical treatment of IE. Of the 87 patients whose WBC normalized within 4 weeks, six died and 15 needed valve surgery.
Conclusion: The normalization of C-reactive protein proved to be a good predictor of a favourable late outcome (surgery, death) of IE. Also WBC count proved useful in the assessment of patients with IE, but the value of ESR was negligible.