Atypical presentation of subclavian steal syndrome mimicking transient ischemic attack: successful endovascular management with angiographic correlation—a case report

Subclavian steal syndrome is an uncommon vascular disorder caused by stenosis or occlusion of the subclavian artery proximal to the vertebral artery origin. It classically presents with vertebrobasilar symptoms such as vertigo, syncope, or diplopia; however, atypical transient neurological presentations may delay diagnosis. A 71-year-old patient presented with recurrent slurred speech and left upper limb weakness without vertigo or diplopia. Examination revealed absent measurable blood pressure and absent radial pulse in the left arm, carotid bruits, and mild distal left upper limb weakness. Computed tomography angiography and digital subtraction angiography demonstrated severe left subclavian artery stenosis with collateral circulation consistent with subclavian steal physiology. The patient underwent successful percutaneous transluminal balloon angioplasty and stenting. Post-stenting angiography confirmed restored antegrade flow without residual steal phenomenon, and the neurological and limb symptoms improved after revascularization. This case emphasizes that subclavian steal syndrome can mimic transient ischemic attack and may present without classic vertebrobasilar symptoms. Careful vascular examination, early vascular imaging, and timely endovascular management are important to prevent diagnostic delay and improve clinical outcomes.