Flow cytometric analysis of reticulated platelets in patients with ischemic stroke.

Reticulated platelets are newly formed platelets containing a residual amount of RNA, and percentage of reticulated platelets (%RP) has been shown to reflect platelet turnover. Recently, a new flow cytometric approach for analyzing %RP in patients with thrombocytopenic disorders has been reported. We measured %RP by flow cytometry using the fluorescent dye thiazole orange (TO) to evaluate platelet kinetics in patients with different clinical categories of ischemic stroke. Patients with ischemic stroke were categorized into lacunar (n=25), atherothrombotic (n=26) and cardioembolic stroke (n=17). %RP was significantly higher in patients with cardioembolic stroke than in controls (n=140). Stepwise multiple regression analysis also showed cardioembolic stroke (R(2)=0.14) to be significant independent predictors of %RP among stroke patients even after adjustment for other factors. We concluded that %RP is increased in patients with cardioembolic stroke, which may reflect increased platelet turnover as a consequence of platelet consumption during thrombogenesis.