Hypercoagulability in acute ischemic stroke: analysis of the extrinsic coagulation reactions in plasma by a highly...

The coagulability of plasmas from 63 patients with acute ischemic stroke (cerebral thrombosis and cerebral embolism) was analyzed by an automated method for prothrombin time using a fluorogenic peptide substrate. The fluorogenic prothrombin time (FPT) of patients' plasmas collected within 48 hr after onset, as expressed as percent of control plasma, was significantly higher in cerebral thrombosis than in an age-matched control group (p less than 0.01). The high values of FPT in cerebral thrombosis patients were observed until the 30th day after onset. On the other hand, FPT values in cerebral embolism patients were not significantly different than that of the control group. Factor VII activity levels in cerebral thrombosis patients were significantly higher than those of the control group and cerebral embolism patients, while levels of factor X activity were not significantly different among these groups. Although FPT and factor VII activity in these stroke patients did not significantly correlate, factor VII activity did correlate well with factor VII antigen. Decreased levels of antithrombin III and elevated levels of FDP and alpha 2-antiplasmin-plasmin complexes were observed only in cerebral embolism patients. Our findings strongly suggest that patients with cerebral thrombosis have been in a hypercoagulable state before the onset of symptoms, which was caused in part by an increase of factor VII activity/antigen, and in part by other unknown mechanisms. In contrast, patients with cerebral embolism were in a low grade consumptive coagulopathy.