Link between platelet activity and outcomes after an ischemic stroke

Platelets play an important role in atherosclerosis and thromboembolic events. We examined the relationship between platelet activity and outcomes after an ischemic stroke.

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.

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.

Results of this study showed that high platelet activity is strongly associated with adverse clinical outcomes after an early ischemic stroke.