" Endarterectomy Combined With Optimal Medical Therapy (OMT) vs OMT Alone in Patients With Asymptomatic Severe Atherosclerotic Carotid Artery Stenosis at Higher-than-average Risk of Ipsilateral Stroke "

Carotid artery stenosis >= 50% affects about 3% of subjects >= 60 years and accounts for up to 15% of all ischemic strokes. Overall, patients with asymptomatic carotid stenosis have a low risk of ipsilateral stroke on modern medical therapy. It is therefore uncertain whether the benefit of carotid surgery still justifies the perioperative risk of stroke or death, and whether revascularisation is good value for money considering competing demands on health services. Several imaging techniques have been developed to identify patients with asymptomatic carotid stenosis at higher-than-average risk of ipsilateral stroke. Specifically, the presence of transcranial Doppler (TCD)-detected embolic signals, intraplaque haemorrhage on magnetic resonance imaging, TCD-measured impaired cerebral vasomotor reserve or rapid stenosis progression have all been shown to involve an at least 3-fold higher risk of ipsilateral stroke. However, before recommendations for clinical practice can be made regarding the use of these tools, their utility must be demonstrated in a formal randomised clinical trial. Our hypothesis is that the use of these predictors can identify a subset of patients with asymptomatic carotid stenosis who could benefit from prophylactic endarterectomy.

Carotid endarterectomy The procedure will be carried out with the technique routinely used by each surgeon. Operative reports and perioperative complications will be collected. CEA will have to be performed as soon as possible, within 60 days after randomization.

Optimal medical therapy OMT will be applied to all patients and started immediately after randomisation.

OMT will be defined by the adhoc committee and follow relevant guidelines. It will include:

• Antiplatelet therapy. If the patient requires anticoagulation for any reason (e.g. atrial fibrillation), the patient should be treated with an appropriate anticoagulant according to the practice at the centre as an alternative to antiplatelet therapy.
• Antihypertensive treatment, if required, to achieve a target blood pressure < 140/90 mmHg (higher targets may be defined by the OMT committee for selected conditions, e.g. contralateral carotid occlusion) Application of structured programs, such as stepped-care approach using ranking of antihypertensive drugs will be used.
• High-dose statin treatment (target LDL < 0.7 g/l). A stepped-care approach with raking of lipid-lowering drugs will also be used.
• Patients smoking at the time of randomisation will be encouraged to stop and join a smoking cessation and support program.
• Other lifestyle modification: reduction of alcohol consumption, choosing healthy food, increasing regular physical activity, reduction of body weight if relevant.

OMT may be modified during the course of the trial to take account revised guidelines or new evidence.