Surgical therapies may be recommended to improve cerebral blood flow if the extracranial internal carotid artery is narrowed by atherosclerosis.

Carotid endarterectomy
This involves opening the artery and scooping out the accumulated atherosclerotic material, along with any thrombus that has formed. This procedure has demonstrated benefits that must be weighed against its risks, including the chance of a heart attack or stroke that may be fatal. Carotid endarterectomy has been shown to be effective in reducing risk of initial or recurrent stroke if there is symptomatic carotid stenosis >70% and if total surgical risk for the paitent is <6%.  Carotid endarterectomy has also been shown to be better than medical therapy for asymptomatic carotid stenosis >60% in men, if total surgical risk is <3%.

Endovascular therapy
Angioplasty with or without stenting is a relatively new procedure for improving flow in the extracranial carotid artery and in some intracranial vessels that are not accessible surgically. In angioplasty, a catheter is used to position a balloon inside the artery. The balloon is then inflated to enlarge the arterial lumen and restore more normal blood flow. In stenting, the artery is held open by a permanent support after the angioplasty is done. Trials are currently underway to compare angioplasty with endarterectomy.

Surgery in the vertebral-basilar system is relatively less common, and there are no randomized controlled trials comparing these procedures with medical therapies. However several small case series suggest that either surgery or angioplasty may be beneficial in situations where medical therapy does not relieve symptoms.