Link between Platelet Activity and Outcomes after an Ischemic Stroke

BACKGROUND: Platelets play an important role in atherosclerosis and thromboembolic events. We examined the relationship between platelet activity and outcomes after an ischemic stroke. METHODS: Using flow cytometry, we serially measured the fractions of circulating platelet activity (CD62p expression) after an ischemic stroke in early (<48 h), recent (day 7), convalescent (day 21) and chronic (day 90) phases in 92 consecutive patients with an ischemic stroke. Patients were classified into high (CD62p expression >3.16%) and low (CD62p expression < or =3.16%) platelet activity groups according to the median value of CD62p expression in the early phase of a stroke. RESULTS: The composite end point--death, recurrent stroke and severe neurological impairment (alive in care), defined as a score of >13 on the National Institutes of Health Stroke Scale--within the first 30 days and at an interval of 8.2 +/- 1.5 months of follow-up was determined for each group. In the first 30 days, the composite end point occurred in 37.0% of patients in the high platelet activity group as compared with 6.5% in the low platelet activity group (p = 0.0004). At a mean follow-up of 8.2 +/- 1.5 months, the composite end point occurred in 36.6% of patients in the high platelet activity group as compared with 10.9% in the low platelet activity group (p = 0.0044). Multiple stepwise logistic regression analysis displayed that high platelet activity (p = 0.011), age (p = 0.013) and the presence of coronary artery disease (p = 0.021) were independently associated with adverse outcomes at the intermediate-term follow-up. CONCLUSIONS: Results of this study showed that high platelet activity is strongly associated with adverse clinical outcomes after an early ischemic stroke.