Abstract 18475: Vegetation Size Does Not Affect Stroke Risk in Infective Endocarditis After 5 Days of Effective Antimicrobial Therapy: An Analysis From the International Collaboration on Endocarditis-Prospective Cohort Study (ICE-PCS)
Introduction: Previous studies have demonstrated a dramatic reduction in stroke risk in infective endocarditis (IE) soon after the initiation of effective antimicrobial therapy. Other studies have shown an increase in stroke risk with increasing vegetation size. There is little information, however, about the interaction of vegetation size and duration of antimicrobial therapy in determining stroke risk. The purpose of this study was to use the ICE-PCS database to assess this interaction. It was hypothesized that vegetation size would have limited impact on stroke risk after several days of antibiotic therapy.
Methods: ICE-PCS enrolled 5495 patients between June 2000 and August 2005 from 61 centers in 28 countries. In the ICE echo substudy database (which used only those centers striving to submit echo data on 100% of subjects), there were 597 cases available with data on vegetation size, stroke incidence, and the timing of stroke in relation to the initiation of effective antimicrobial therapy.
Results: The incidence of stroke in the study group was 36.0% (215/597). There was a trend towards a higher incidence of stroke in patients with vegetations greater than 5mm as opposed to less than 5mm (37.7% [187/496] vs. 25% [11/44]; OR 1.82, 95% CI .90–3.69), although this finding did not reach statistical significance (p=.10). Only 6.4% (44/581) of the study patients had a stroke after 5 days of effective antimicrobial therapy. The rates of stroke after 5 days of therapy did not differ among categories of vegetation size. There was no difference in stroke rate if vegetation size was dichotomized (<5mm vs. >5mm, <10mm vs >10mm, etc.) or if comparisons were made across size intervals (0–5mm, 5–10 mm, etc.) (See Table).
Conclusion: The risk of stroke in IE is low after five days of antimicrobial therapy, and is similarly low regardless of vegetation size. This information should be taken into account whenever embolic risk plays a part in clinical decision making in infective endocarditis.
- © 2010 by American Heart Association, Inc.