A journey into the carotid artery microenvironment in high resolution: challenging the stenosis-symptoms paradigm.

Atherosclerosis is the most frequent cause of extracranial cerebrovascular disease, and represents an important cause of stroke and transient ischemic attack, being responsible for up to 15% to 20% of all ischemic strokes (1). Carotid artery stenosis has long been recognized as an important risk factor. In most studies of carotid artery stenosis intervention, clinically important stenosis, beyond which point the stroke risk is increased, are those greater than 50% to 60% diameter stenosis (2). Patients with asymptomatic carotid stenosis are at increased annual risk (2% to 5%) for ipsilateral carotid territory ischemic stroke (3,4).