Blood coagulation and fibrinolysis after experimental subarachnoid hemorrhage

Aneurysmal rebleeding poses a serious risk in patients with subarachnoid hemorrhage (SAH). Studies have shown that antifibrinolytic therapy with tranexamic acid has a dramatic effect on the rate of rebleeding. Therefore, changes in the fibrinolytic system could be hypothesized. We have used an experimental SAH rat model to demonstrate serial changes in the haemostatic system as evaluated by ThromboelastographyA (R) (TEG). In the SAH group, a shorter reaction time (R-time) and higher maximum amplitude (MA) were observed. In the saline group, only a shorter R-time was observed. The study has shown that a hypercoagulable state is present immediately after experimental SAH is induced as determined by TEG. The reduction in R-time and rise in MA observed in the SAH group indicate that blood in the subarachnoid space is necessary to accomplish a full systemic coagulation response. This abnormality in coagulation profile seems to be a response to the acute traumatic event caused by induction of SAH.