Testing for asymptomatic carotid disease in patients with arterial disease elsewhere

Moderate to severe asymptomatic carotid atherosclerosis is found in 2–7% of the European population aged over 60 years; however the prevalence is highest in those with peripheral arterial disease (25%).The number of individuals needed to scan to prevent one extra stroke through referral for endarterectomy is 143 for claudicants, 250 for those with aortic aneurysmal disease and 333 for those with contralateral symptomatic carotid stenosis.The cost per stroke saved with surgery is approximately £76,000, through a policy of testing claudicants for asymptomatic carotid atherosclerosis, then offering carotid endarterectomy. Through implementing large scale testing of claudicants aged 60 years in England and Wales, 0.2% of the total number of strokes per year would be saved at a cost of £17 million. The main cost driver is the amount of unnecessary surgery performed (number needed to treat=20).