Heparin Treatment in Aneurysmal Subarachnoid Hemorrhage: A Review of Human Studies.

Aneurysmal subarachnoid hemorrhage (aSAH) remains a significant cause of stroke disability despite gradual reductions in physical morbidity and mortality. Heparin is an effective anti-inflammatory agent and may potentially prevent delayed neurological injury in the days to weeks after the hemorrhage. Various human studies have shown the safety of a continuous infusion of low-dose unfractionated heparin in the setting of subarachnoid hemorrhage as well as its efficacy in minimizing delayed neurological deficits including symptomatic cerebral vasospasm, vasospasm-related infarction, and cognitive dysfunction. Studies have also shown mixed results with low-molecular-weight heparin usage in this patient population. Heparin treatment is not associated with significant hemorrhagic complications; however, vigilance is essential for early detection of heparin-induced thrombocytopenia in order to prevent devastating sequelae. Multicenter randomized controlled trials are necessary for objective characterization of the effects of heparin.