Coil embolization of intracranial dissecting vertebral artery aneurysms with subclavian steal.

Subclavian steal phenomenon occurs when cerebral blood flow is diverted to supply the arm. We report 3 patients with asymptomatic subclavian steal phenomenon with retrograde blood flow in the vertebral artery who presented with subarachnoid hemorrhage due to dissecting aneurysms of the involved vertebral artery. The association of subclavian steal phenomenon complicated by subarachnoid hemorrhage due to dissecting vertebral aneurysms has not been previously described.