Asymptomatic carotid stenosis: how should it be managed?

OBJECTIVE: To discuss the implications of recent studies on carotid endarterectomy for asymptomatic carotid stenosis. DATA SOURCES: Trials of the effectiveness of carotid endarterectomy in asymptomatic carotid stenosis, including the Asymptomatic Carotid Atherosclerosis Study (ACAS). RESULTS: In the ACAS study, carotid endarterectomy for asymptomatic moderate to severe carotid stenosis (60%-99% luminal obstruction) reduced the absolute risk of ipsilateral stroke or death at five years by 5.9%. This means that about 17 patients need to be operated on to prevent one stroke or death over five years. To operate on all Australians with asymptomatic 60%-99% carotid stenosis would cost an estimated $A1.24 billion and prevent 800 strokes per year, or only 3% of all first strokes in Australia. RECOMMENDATIONS: In order to identify who will benefit from carotid endarterectomy and who will remain symptom-free without it, patients should continue to be allocated to the ongoing Asymptomatic Carotid Surgery Trail. Otherwise, carotid endarterectomy should be reserved for patients at high risk of stroke (i.e., with 95%-99% carotid stenosis) who are medically fit for surgery and willing to take the small short term risk of surgery for a possible greater long term benefit.