Cerebral Vasospasm and Delayed Cerebral Ischemia after Warfarin-Induced Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) associated with anticoagulation is a rare event. About 30% of in-hospital patients with aneurysmal SAH develop delayed cerebral ischemia (DCI); however, the occurrence of vasospasm and DCI in patients with nonaneurysmal SAH is still controversial.

This study is a case report of a patient experiencing an anticoagulation-induced SAH complicated by vasospasm and DCI.

A 38-year-old woman presented to our hospital with a sudden onset of severe headache. Head computed tomography (CT) showed bleeding in the posterior fossa subarachnoid space. There was no aneurysm in the CT angiography. The International Normalized Ratio at hospital admission was 9. Anticoagulation was held, and she was treated with fresh frozen plasma (15 mg/kg) and parenteral vitamin K. The patient remained in the intensive care unit and had daily transcranial Doppler (TCD) monitorization. TCD examination detected increased blood flow velocities in the basilar and vertebral arteries, meeting criteria for definitive vasospasm. CT angiography confirmed the presence of posterior circulation vasospasm. Magnetic resonance (MR) imaging 2 weeks after the bleeding showed a small area of restricted diffusion in the left superior cerebellar artery territory. MR angiography showed resolution of the vasospasm at this time point and TCD velocities normalized.

In conclusion, this case report suggests that vasospasm and consequent DCI is a possible mechanism of secondary lesion after anticoagulation-induced SAH. To our knowledge, this is the first report of vasospasm and DCI due to warfarin-associated SAH.