Coronary Artery Stenosis
Coronary artery stenosis is a narrowing of one or more coronary arteries that reduces blood flow to the heart muscle. It is most often caused by atherosclerotic plaque buildup, although less common causes include spasm, dissection, inflammation, congenital anomalies, and prior radiation. The clinical importance of a stenosis depends on its severity, location, the amount of heart muscle it supplies, and how it affects blood flow. Imaging—including coronary CT angiography and invasive coronary angiography—plays a central role in identifying and grading stenoses and guiding treatment.
What is it?
The coronary arteries are the vessels that supply oxygen-rich blood to the heart muscle. Coronary artery stenosis is a narrowing of the inside (lumen) of one or more of these arteries, which can reduce the amount of blood reaching the muscle they supply—particularly during physical activity or stress. The narrowing is typically measured as a percentage of the lumen diameter compared with the surrounding normal artery, with stenoses generally classified as minimal, mild, moderate, severe, or, when there is complete blockage, total occlusion.
The most common cause of coronary stenosis is atherosclerotic plaque—a buildup of cholesterol, inflammatory cells, smooth muscle, and calcium within the artery wall. Over time, plaque can grow and bulge into the lumen, narrowing the channel through which blood flows. Less common causes include coronary artery spasm (sudden, temporary tightening of a coronary artery), spontaneous coronary artery dissection (a tear within the artery wall), coronary embolism (a clot or other material traveling to a coronary artery), vasculitis, prior chest radiation, congenital anomalies, and rare conditions affecting the artery wall.
The clinical importance of a coronary stenosis depends on several factors. The most significant include the severity of the narrowing, the location (with more proximal stenoses generally affecting more heart muscle), the amount of myocardium supplied by the affected artery, the presence and quality of collateral blood vessels, and the patient’s overall pattern of disease. Importantly, the percentage narrowing seen on imaging is one of several factors that influence symptoms and risk; the physiological significance—whether the stenosis actually limits blood flow—is increasingly evaluated using tools such as fractional flow reserve (FFR) or CT-derived FFR.
Symptoms vary widely. Many people with mild to moderate stenoses have no symptoms, particularly when blood flow can still meet the heart’s needs. As stenoses become more severe, classic angina may develop: chest pressure, tightness, or discomfort that occurs with exertion or stress and improves with rest. Symptoms may also include shortness of breath, fatigue, reduced exercise tolerance, lightheadedness, or pain radiating to the neck, jaw, arm, or back. Some patients—particularly women, older adults, and those with diabetes—may have atypical symptoms or no clear chest pain at all. When a stenotic plaque ruptures or otherwise becomes unstable, sudden formation of a blood clot can lead to acute coronary syndromes such as unstable angina or heart attack, with severe and sustained symptoms.
Evaluation typically combines clinical assessment with testing. ECG provides information about heart rhythm and signs of prior or ongoing ischemia. Stress testing—using exercise or pharmacologic stress with ECG, echocardiography, or nuclear imaging—evaluates how the heart performs under increased demand and helps identify functionally significant disease. Coronary CT angiography (CCTA) uses contrast-enhanced CT to directly visualize the coronary arteries and is increasingly used as a first-line test in patients with stable chest pain and intermediate risk; modern CCTA can also provide functional information through CT-derived FFR. Invasive coronary angiography, performed during cardiac catheterization, remains the standard for definitive evaluation and is typically used when intervention is anticipated or when noninvasive testing is inconclusive. FFR and other physiologic measurements help determine whether a moderate stenosis is causing limited blood flow.
Important to Know
Management of coronary artery stenosis is highly individualized and depends on the severity and location of narrowing, whether it is causing symptoms, how much heart muscle is at risk, and the patient’s overall cardiovascular risk. Even significant stenoses can sometimes be managed primarily with medications and lifestyle changes if symptoms are well controlled and the amount of muscle at risk is limited.
Lifestyle measures are foundational: not smoking, regular physical activity, a heart-healthy diet, weight management, limited alcohol, stress reduction, good sleep, and treatment of sleep apnea when present. These steps can slow plaque progression, improve symptoms, and reduce the risk of future cardiovascular events.
Medications play a central role for nearly all patients. Statins and other lipid-lowering therapies reduce LDL cholesterol, stabilize plaque, and reduce the risk of heart attacks. Blood pressure control, diabetes management (including newer agents with cardiovascular benefit), antiplatelet medications, and anti-anginal medications (such as beta-blockers, calcium channel blockers, and nitrates) are tailored to individual needs.
When stenoses are significant and cause persistent symptoms despite optimal medical therapy, threaten substantial amounts of heart muscle, or occur in the setting of an acute coronary syndrome, procedures may be considered. Percutaneous coronary intervention (PCI) uses catheter-based techniques, often including stents, to open narrowed arteries. Coronary artery bypass grafting (CABG) creates new pathways around blocked arteries using vessels from elsewhere in the body. The choice between PCI, CABG, and continued medical therapy is individualized, often guided by formal assessment of the pattern and physiologic significance of the stenoses.
Cardiac rehabilitation—a structured program of supervised exercise, education, and risk factor management—is highly beneficial after PCI, CABG, and in many patients with stable disease. Care is typically coordinated by primary care clinicians and cardiologists, with input from interventional cardiologists, cardiothoracic surgeons, electrophysiologists, dietitians, and others.
Even moderate or non-flow-limiting stenoses are important to recognize, because they reflect ongoing atherosclerotic disease and increased risk of future events. Aggressive risk factor control in patients with any identified coronary disease has been shown to substantially improve outcomes.
Red flag symptoms include sudden severe chest pain or pressure (especially radiating to the jaw, arm, or back), severe shortness of breath, fainting, palpitations with lightheadedness, signs of stroke, profuse sweating, or signs of shock. These warrant immediate emergency evaluation, as they may indicate a heart attack or another life-threatening cardiovascular condition.