Effect of antifibrinolytic therapy on subarachnoid fibrosis in dogs after experimental subarachnoid haemorrhage.

The effect of antifibrinolytic therapy on posthaemorrhagic subarachnoid fibrosis was observed experimentally in dogs with the scanning electron microscope (SEM). The subchronic subjects, given intravenous injections of tranexamic acid (1 mg/day) for 12 days and sacrificed 3 weeks after cisternal blood injection, showed residual clot with thick fibrosis, especially around the haemorrhage. The chronic subjects, to which the same procedure was applied and which were sacrificed three months after cisternal blood injection, showed significant increases in the subarachnoid fibrosis, most remarkably in the parasagittal region. Tranexamic acid is widely used for preventing the recurrence of subarachnoid haemorrhage. However, it was revealed in this study that antifibrinolytic therapy might increase chronic posthaemorrhagic subarachnoid fibrosis, which is considered to be responsible for communicating hydrocephalus by disturbing epicortical CSF flow.