Antifibrinolytic therapy for aneurysmal subarachnoid haemorrhage

Treatment to prevent blood-clot dissolution does not improve outcome after subarachnoid haemorrhage. A subarachnoid haemorrhage (SAH) is a bleed in the so-called subarachnoid space, which is the very small space between the brain and the skull, and which contains blood vessels that supply the brain. The cause of the bleeding usually is a rupture of a weak spot in one of these vessels. This weak spot is like a small balloon, or blister, which is called an aneurysm. A subarachnoid haemorrhage is a relatively uncommon type of stroke; it accounts for about 1 in 20 (5%) of all strokes. In contrast to common types of stroke, a subarachnoid haemorrhage often occurs at a relatively young age: half the patients are younger than 60 years. The outcome of patients after subarachnoid haemorrhage is generally poor: half the patients die within one month after the haemorrhage, and of those who survive the first month, half remain dependent for help with activities of daily living (e.g.: walking, dressing, bathing). One of the most important causes of poor outcome after SAH is the occurrence of a complication called rebleeding. Rebleeding is thought to originate from dissolution of the blood-clot at the site of the ruptured aneurysm. This dissolution probably results from natural fibrinolytic activity in the subarachnoid space after SAH. Since antifibrinolytic agents reduce this activity, antifibrinolytic therapy was suggested as a means of reducing the occurrence of rebleeds and therefore to result in a decrease of poor outcome after SAH. The review demonstrates that antifibrinolytic treatment does indeed reduce the risk of rebleeding. Surprisingly, clinical outcome - in terms of survival and being independent in activities of daily living - does not improve by antifibrinolytic treatment. Further analysis in the review shows that the beneficial effect of a reduced risk of rebleeding is in fact nullified by an increase in one of the other complications. Because there is no overall beneficial effect of antifibrinolytic treatment on outcome the reviewers conclude that antifibrinolytic drugs should not be used in the treatment of patients with aneurysmal SAH.