This ischemia can either be temporary, yielding a transient ischemic attack (TIA), or permanent resulting in a thromboembolic stroke.

The plaque build-up can narrow or constrict the artery lumen, a condition called stenosis.

National Institute for Health and Clinical Excellence (NICE) guidelines recommend that people with moderate to severe (50–99% blockage) stenosis, and symptoms, should have "urgent" endarterectomy within 2 weeks.

Pieces of plaque can break off and block the small arteries above in the brain, which causes a stroke.

[16] Typically duplex ultrasound scan is the only investigation required for decision making in carotid stenosis as it is widely available and rapidly performed.

The investigation chosen will depend on the clinical question and the imaging expertise, experience and equipment available.

[23] The U.S. Preventive Services Task Force recommends against routine screening for carotid artery stenosis in those without symptoms as of 2021.

[citation needed] The goal of treating carotid artery stenosis is to reduce the risk of stroke.

The type of treatment depends on the severity of the disease and includes:[citation needed] Clinical guidelines (such as those of the American Heart Association (AHA)[28] and National Institute for Clinical Excellence (NICE)[29]) recommend that all patients with carotid stenosis be given medications to control their vascular risk factors, usually blood pressure lowering medications (if they have hypertension), diabetes medication (if they have diabetes), and recommend exercise, weight reduction (if overweight) and smoking cessation (for smokers).

[citation needed] According to the American Heart Association, interventions beyond medical management is based upon whether patients have symptoms:[citation needed] All interventions for carotid revascularization (carotid endarterectomy, carotid stenting, and transcarotid artery revascularization) carry some risk of stroke; however, where the risk of stroke over time from medical management alone is high, intervention may be beneficial.