The vast majority of patients with carotid plaque do not have any symptoms. They are usually detected on physical examination by carotid ultrasound. Smaller plaques generally do not have a significant impact on the blood supply to the brain. Larger carotid plaques can lead to severe narrowing of the carotid artery and may present with symptoms such as dizziness and transient blackouts. If plaque has formed in the carotid artery, it often indicates that plaque may also exist in other parts of the systemic arteries, such as the coronary arteries, when the risk of acute myocardial infarction is greatly increased.