Asymptomatic Carotid Surgery Trials (ACST) 
Asymptomatic Carotid Surgery Trials (ACST)
Click for Full ACST 2 Protocol or Summary Protocol
Background
Atherosclerotic narrowing of the carotid arteries can cause stroke. In Europe at least one million people and about 100,000 people in the UK have severe stenosis (narrowing) in one or both or their carotid arteries.
ACST-1 (1993-2003) was an multi centre international trial comparing CEA with best medical treatment versus no immediate procedure. The trial randomised 3000 patients with substantial carotid artery disease but no recent neurological symptoms (stroke or TIA). The five year paper (May 2004) showed that carotid endarterectomy (CEA) reduced the risk of stroke when compared to best medical treatment alone.
Its successor, ACST-2, is a large simple international randomised trial comparing CEA with CAS in patients with asymptomatic carotid stenosis where there is substantial uncertainty which treatment is more appropriate. ACST-2 seeks to randomise such individuals between CEA and CAS to compare both the immediate hazards of the two procedures (1 month), and the subsequent stroke rates over the next 5 to 10 years.
ACST-2 can only succeed if many thousands of patients are randomised. The workload per patient has been minimised, so that the study can be integrated easily into routine health care.
The need for a large scale randomised trial comparing CEA vs CAS
A Cochrane meta-analysis of CEA vs CAS trials (mainly in symptomatic patients) stated that ‘the current evidence does not support a widespread change in clinical practice away from recommending CEA as the treatment of choice for suitable carotid artery stenosis. There is a strong case to continue recruitment in the current randomised trials comparing carotid stenting with endarterectomy'. Multicentre trials, undertaken mainly in symptomatic patients (eg, ICSS, SPACE, EVA-3S, CREST & SAPPHIRE ) have not yet resolved this uncertainty. Much larger trials are now needed, particularly in asymptomatic patients. The European Stroke Initiative recommendations for stroke management supported this, and stated that ‘carotid angioplasty (balloon dilatation), with or without stenting, is not routinely recommended for patients with asymptomatic carotid stenosis. It may be considered in the context of randomised clinical trials' .
Randomisation Starts 15th January 2008
