Ruptured vertebrobasilar junction aneurysm unmasking subclavian steal syndrome

BACKGROUND: Subclavian steal occurs due to stenosis or occlusion of the subclavian artery or innominate artery proximal to the origin of the vertebral artery. Often asymptomatic, the condition may be unmasked due to symptoms of vertebrobasilar insufficiency triggered by strenuous physical exercise involving the affected upper limb. The association of vertebrobasilar junction (VBJ) aneurysms with subclavian steal syndrome has been rarely reported. Hereby, we present a case of VBJ aneurysm associated with subclavian steal treated successfully with endovascular coiling. CASE DESCRIPTION: A 65-year-old female presented in the emergency department with acute severe headache and vomiting with no focal neurological deficits. Non-contrast computed tomography of the brain showed modified Fischer Grade 3 subarachnoid hemorrhage. Subsequent digital subtraction angiogram (DSA) showed VBJ aneurysm directed inferiorly with the left subclavian artery occlusion. There was retrograde filling of the left vertebral artery on right vertebral injection, confirming the diagnosis of subclavian steal. Balloon assisted coiling of the VBJ aneurysm was performed while gaining access through the stenotic left vertebral artery ostium which provided a more favorable hemodynamic stability to the coil mass. CONCLUSION: Subclavian steal exerting undue hemodynamic stress on vertebrobasilar circulation can be an etiological factor for the development of the flow-related aneurysms. Access to the VBJ aneurysms may be feasible through the stenosed vertebral artery if angioplasty is performed before the coiling of the aneurysm.