Time course of platelet activation and von Willebrand factor in patients with non-valvular atrial fibrillation after ischemic stroke - Evaluation of prognostic determinants

Background: The present study investigated serial changes in platelet activation (expressed by CD62p) and von Willebrand factor (VWF), and the correlation between increased CD62p expression, VWF and brain infarct volume (BIV: measured by magnetic resonance imaging), and prognostic determinants in non-valvular atrial fibrillation (NVAF) patients after acute ischemic stroke (IS). Methods and Results: CD62p expression and plasma VWF concentrations were serially measured (<48h, on days 7, 21 and 90) using flow cytometry and enzyme-linked immunosorbent assay, respectively after acute IS in 61 NVAF patients. CD62p expression and VWF concentrations were also examined in 50 NVAF-risk control and 30 healthy individuals. The VWF concentration had no significant changes at 4 intervals among the patients and did not differ among 3 groups at acute stroke phase. CD62p expression was significantly higher in the acute phase after IS than in both control groups (both p<0.0001). However, CD62p expression declined to a significantly lower level on day 7 and to a substantially lower level thereafter (p<0.0001). CD62p expression did not differ on day 90 in the 3 groups (both p>0.5). Linear regression analysis showed that BIV and modified Rankin scale score (>3) were independently associated with increased CD62p expression (<48h) (both p<0.01). Furthermore, the Cox proportional hazards model showed that BIV was the only independent predictor of intermediate-term (8.8±4.4 months) combined recurrent stroke and death. Conclusions: The CD62p expression, which reflected increased BIV, was significantly increased in NVAF patients in acute-phase IS and substantially declined thereafter. The BIV was predictive of unfavorable intermediate-term clinical outcomes.