European neurology
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21 patients (aged 28-81 years) with recent subarachnoid hemorrhage (10 saccular aneurysms, 3 arteriovenous angiomas, 8 normal angiograms) were continuously infused with tranexamic acid at a dosage of 5 g daily for up to 14 days. Therapy was surveyed by daily measurement of the available plasminogen activity (aPl) with the chromogenic substrate S-2251 and by a modified bioassay, whereby the concentration of tranexamic acid was determined thrombelastographically and expressed as antifibrinolytic equivalent. ⋯ Intra- and interindividual changes were relatively small for aPl, when compared with the antifibrinolytic equivalent measured by the bioassay. In 2 elderly patients tranexamic acid infusion had to be terminated because of clinical and laboratory signs of disseminated intravascular coagulation, whereby aPl fell below the therapeutic range, elucidating that this method is a sensitive indicator for a hypercoagulable state and useful for the surveillance of therapy with antifibrinoltic agents.