Asymptomatic Carotid Surgery Trial-2 (ACST-2): an international randomised trial to compare carotid endarterectomy with carotid artery stenting to prevent stroke

Around 5,000 patients with narrowed carotid arteries will be randomly assigned to either surgical removal of the blockage or a less invasive stent procedure, in a head-to-head trial to determine which better prevents stroke. Why this matters: About one million adults in Europe have atherosclerotic narrowing of one or both carotid arteries, putting them at substantially increased risk of stroke over the next 5 to 10 years, even with long-term medication. Previous trials showed that carotid endarterectomy (CEA) – surgical removal of the plaque – greatly reduces stroke risk, but carries a 3% risk of peri-operative stroke or death. Carotid artery stenting (CAS) is an increasingly popular alternative that may have lower immediate risks, but no large trial has reliably compared the two. Potential impact: If ACST-2 shows that CAS has lower peri-operative risks while matching CEA’s long-term benefits, it could shift clinical practice toward the less invasive procedure, reducing hospital stays and recovery times for thousands of patients. If CEA proves superior, it would reaffirm surgery as the standard. Either way, the findings will directly affect treatment decisions for the many patients with carotid stenosis who face a daily risk of disabling or fatal stroke. The trial also includes health economic evaluation to assess quality-of-life and cost-effectiveness.