Carotid Artery Disease: Warning Signs Before Stroke

Stroke is the fifth leading cause of death and the leading cause of long-term disability in the United States, according to the CDC. What most people do not know is that up to 80 percent of strokes are considered preventable, according to the American Heart Association^[1], and that carotid artery disease, which develops silently over decades, accounts for approximately 15 to 20 percent of all ischemic strokes. The window to intervene is measured in years. The stroke itself happens in seconds.

What Carotid Artery Disease Is

The carotid arteries are the two main vessels that run up either side of the neck, supplying blood to the brain. Carotid artery disease is the accumulation of atherosclerotic plaque within these vessels. Over time, plaque narrows the artery, restricting blood flow. More dangerously, unstable plaque can rupture, causing a clot that travels directly to the brain.

Carotid plaque typically begins accumulating at the carotid bifurcation, the point where the common carotid artery divides into the internal and external branches. This is a zone of turbulent blood flow, which promotes endothelial damage and accelerates plaque deposition. The internal carotid artery, which supplies the brain directly, is the critical vessel.

Why Carotid Disease Has No Warning Signs

Carotid stenosis is asymptomatic in the majority of people who have it. The artery narrows gradually over years, and the brain compensates through its collateral circulation. Only when stenosis becomes severe, typically above 70 percent, does flow-related ischemia begin to produce symptoms. And often, the first clinical event is a stroke rather than a warning sign.

A transient ischemic attack, or TIA, is sometimes called a mini-stroke. It produces stroke symptoms that resolve completely within 24 hours. TIAs are caused by brief interruptions of blood flow to the brain, often from a small clot that breaks off from a carotid plaque. Critically, a TIA is a major warning: approximately 10 to 15 percent of people who have a TIA will have a full stroke within 90 days.^[1]

The Carotid Duplex Ultrasound: What It Detects

Carotid duplex ultrasound combines B-mode imaging, which creates detailed structural pictures of the artery wall, with Doppler flow analysis, which measures blood velocity. Together these two modalities assess plaque presence, plaque characteristics, stenosis degree, and flow hemodynamics simultaneously.

The study evaluates both the right and left carotid systems. It measures intima-media thickness as a marker of subclinical atherosclerosis, characterizes any plaque found in terms of size, echogenicity, and surface features, and quantifies stenosis using velocity criteria validated against angiographic studies.

When Carotid Stenosis Is Found: What Happens Next

What happens next depends entirely on how severe the stenosis is. Mild narrowing usually means monitoring and risk factor control, while severe stenosis can require referral to a vascular specialist for procedures like carotid endarterectomy or stenting. Here is how recommendations break down by stenosis percentage:

• ›Mild stenosis under 50 percent: medical management, risk factor control, and surveillance imaging every two to three years
• ›Moderate stenosis 50 to 69 percent: intensified medical management, more frequent surveillance, and symptom monitoring
• ›Severe stenosis 70 to 99 percent: cardiology or vascular surgery referral for consideration of carotid endarterectomy or stenting^[2]
• ›Symptomatic stenosis with TIA or stroke history: urgent evaluation as the 90-day stroke risk is highest in this group

Who Should Have a Carotid Duplex

• ›Adults over 55 with any cardiovascular risk factor
• ›Anyone with a history of transient ischemic attack or prior stroke
• ›Patients with known coronary artery disease, where carotid disease prevalence is 20 to 40 percent^[3]
• ›Individuals with a carotid bruit detected on physical examination
• ›Anyone with a family history of stroke before age 65
• ›Patients with hypertension, diabetes, or smoking history of any duration