The effect of short-term antifibrinolytic therapy on experimental vasospasm.

Background: Antifibrinolytic therapy is effective in preventing rebleeding in cases of aneurysmal subarachnoid hemorrhage (SAH). The major disadvantage of this therapy is the increase in ischemic complications, which is supposed to be due to cerebral vasospasm. In this study the effect of short-term antifibrinolytic therapy on arterial vessel narrowing after SAH was investigated utilizing the rat femoral artery vasospasm model.

Methods: Twenty-four rats were divided into four groups of six animals each. Autologous blood (0.1 mL) was applied to the 1-cm segment of right femoral artery wrapped with a silicone cuff. In Group 1 the animals did not receive any treatment. In Groups 2, 3, and 4 150 mg/kg tranexamic acid (AMCA) was given orally for 3, 5, or 7 days respectively, starting from postoperative day 1. A 1 cm segment of each femoral artery was harvested on the 8(th) postoperative day. Morphologic analyses were performed using the parameters, radial wall thickness and cross luminal area under the light microscope. In addition, two samples from each group were examined by transmission electron microscope (TEM) to confirm the morphologic changes.

Results: There was a gradual decrease in cross luminal area and gradual increase in vessel wall thickness directly proportional with time. However, the vasospastic changes that occurred in Group 2 (received AMCA for 3 days) were not significantly different from those of Group 1 (nontreated).

Conclusion: It was concluded that antifibrinolytic treatment for the first 3 days may prove useful in cases of clinical aneurysmal SAH. However, if this treatment is used for more than 3 days, arterial vessel narrowing is significantly increased.