"The aim of this study was to determine the extent of change in platelet and coagulation markers in the acute phase of ischemic stroke and to assess the utility of marker mesurement in stroke subtype classification.  Urinary 11-dehydro-thromboxane B₂ (11-deTXB₂), a marker of in vivo platelet activation, and markers of coagulation activation, including prothrombin fragment 1 +2 (F1 + 2), thrombin-antithrombin complex (TAT) and fibrinogen, were measured in 25 patients with ischemic stoke within 24 h of onset symptoms. Eight patients taking aspirin at the time of the stroke had signficantly lower 11-dTXB2 values than patients not taking aspirin (964 vs. 4,314 pg/mg of creatinine P=0.0007).  Stroke patients not taking aspirin had significantly higher 11-dTXB2 concentration than age-matched controls (4,314 vs. 1,788 pg/mg of creatinine; P= 0.0006)."