The relationship between the initiation of antimicrobial therapy and the incidence of stroke in infective endocarditis: an analysis from the ICE Prospective Cohort Study (ICE-PCS).

BACKGROUND: Embolic events to the central nervous system are a major cause of morbidity and mortality in patients with infective endocarditis (IE). The appropriate role of valvular surgery in reducing such embolic events is unclear. The purpose of this study was to determine the relationship between the initiation of antimicrobial therapy and the temporal incidence of stroke in patients with IE and to determine if this time course differs from that shown for embolic events in previous studies. METHODS: Prospective incidence cohort study involving 61 tertiary referral centers in 28 countries. Case report forms were analyzed from 1437 consecutive patients with left-sided endocarditis admitted directly to participating centers. RESULTS: The crude incidence of stroke in patients receiving appropriate antimicrobial therapy was 4.82/1000 patient days in the first week of therapy and fell to 1.71/1000 patient days in the second week. This rate continued to decline with further therapy. Stroke rates fell similarly regardless of the valve or organism involved. After 1 week of antimicrobial therapy, only 3.1% of the cohort experienced a stroke. CONCLUSIONS: The risk of stroke in IE falls dramatically after the initiation of effective antimicrobial therapy. The falling risk of stroke in patients with IE as a whole precludes stroke prevention as the sole indication for valvular surgery after 1 week of therapy.