Carotid stenosis is a progressive narrowing of the arteries in the neck that supply blood to the brain (carotid artery disease). This narrowing restricts the flow of oxygenated blood, significantly increasing the risk of an ischemic stroke. A stroke occurs when blood supply to the brain is cut off, causing brain cells to die. Understanding the condition, recognizing warning signs, and knowing diagnostic and treatment options are important steps in management.
Understanding the Carotid Arteries and Stenosis
The carotid system consists of two main arteries, one on each side of the neck, delivering most of the blood from the heart up to the brain, face, and head. Near the jaw, the common carotid artery divides into the external carotid artery (supplying the face and scalp) and the internal carotid artery (supplying the brain). The area where the common carotid splits, known as the bifurcation, is the most common site for plaque buildup.
Stenosis refers to the narrowing of the artery, and the underlying cause is nearly always atherosclerosis. Atherosclerosis is a disease process where fatty substances, cholesterol, and other waste products accumulate along the inner lining of the artery wall, forming plaque. This buildup stiffens the artery and gradually decreases the size of the lumen, the inner channel through which blood flows.
Several health conditions and lifestyle choices accelerate plaque formation. High blood pressure damages artery walls, creating sites where plaque adheres. Elevated cholesterol, particularly low-density lipoprotein (LDL), provides the material for deposits. Other major risk factors include diabetes, which negatively impacts blood vessel health, and smoking, which damages the arterial lining and promotes clotting.
Recognizing the Warning Signs
Carotid stenosis is often a “silent” disease, meaning many people have a significant blockage without symptoms. The first indication of the condition can be a full-blown stroke. However, the primary warning sign of dangerous narrowing is a transient ischemic attack (TIA), often called a “mini-stroke.”
A TIA is a temporary shortage of blood flow to the brain, causing stroke-like symptoms that resolve completely within minutes or an hour. These temporary blockages occur when a small piece of plaque or a blood clot breaks off and briefly lodges in a smaller artery before dissolving. Symptoms include sudden weakness or numbness on one side of the body, such as the face, arm, or leg.
Other TIA symptoms include sudden difficulty speaking or understanding speech and temporary vision loss in one eye, sometimes described as a curtain coming down. Although a TIA does not cause permanent damage, it signals a high risk for a major stroke, particularly within 48 hours. Recognizing these symptoms and seeking immediate medical attention can prevent a devastating stroke.
Diagnostic Procedures
Confirming carotid stenosis begins with a physical examination, where a doctor may listen to the neck for an abnormal sound called a bruit, indicating turbulent blood flow. The primary diagnostic test is the Carotid Duplex Ultrasound. This non-invasive test uses sound waves to create images of the artery structure and measure the speed of blood flow.
The ultrasound allows physicians to estimate the degree of narrowing (stenosis) by analyzing flow characteristics and comparing the blockage diameter to the normal artery diameter. Severity is classified into categories like mild, moderate, or severe, which directly influences the treatment decision. If ultrasound results are unclear or an interventional procedure is considered, other imaging techniques may be used.
Confirmatory tests include Computed Tomography Angiography (CTA) or Magnetic Resonance Angiography (MRA). Both CTA and MRA provide detailed, cross-sectional images of the arteries and the plaque, offering a complete picture of the anatomy before potential surgery. Ultrasound remains the first choice for screening, with complex imaging reserved for specific cases or intervention planning.
Treatment Approaches
Management of carotid stenosis is tailored to the patient, based primarily on the severity of narrowing and whether symptoms have occurred. For patients with mild to moderate stenosis or those without symptoms, the initial approach is intensive medical management. This strategy focuses on aggressive control of risk factors through lifestyle modifications, such as a heart-healthy diet, increased physical activity, and stopping smoking.
Pharmacological therapy plays a significant role in medical management, aiming to stabilize plaque and prevent blood clots. Antiplatelet medications like aspirin are commonly prescribed to reduce clotting, while statins lower cholesterol and help regress plaque buildup. Blood pressure medications are administered to reduce strain on the artery walls, slowing the progression of the disease.
Interventional procedures are generally reserved for patients with severe stenosis (typically greater than 70%) or those who have experienced symptoms like a TIA. The traditional surgical option is Carotid Endarterectomy (CEA), where a surgeon makes an incision in the neck, opens the carotid artery, and physically removes the plaque. This procedure is considered the gold standard for many patients.
A less invasive option is Carotid Artery Stenting (CAS), where a small mesh tube (stent) is deployed inside the artery to push the plaque aside and keep the vessel open. This procedure is often performed by threading a catheter from an artery in the groin or directly from the neck (TransCarotid Artery Revascularization, TCAR). The choice between CEA and stenting involves discussion with the vascular specialist, considering the patient’s overall health, anatomy, and associated risks.