Coronary Stenosis
Coronary stenosis is the narrowing of one or more coronary arteries—the blood vessels that supply oxygen-rich blood to the heart muscle. This narrowing is most commonly caused by atherosclerotic plaque buildup within the artery walls, reducing blood flow to the heart. When the coronary arteries become significantly narrowed (typically 50-70% or more), the heart may not receive adequate oxygen during times of increased demand such as exercise or stress, causing chest pain (angina). Severe stenosis or complete blockage can lead to heart attack. Coronary stenosis is the underlying problem in coronary artery disease, the leading cause of death in the United States.
What is it?
The heart has three main coronary arteries: the left anterior descending (LAD) artery, which supplies the front and left side of the heart; the left circumflex artery, which wraps around the left side; and the right coronary artery (RCA), which supplies the right side and bottom of the heart. These arteries branch extensively, forming a network that delivers oxygen and nutrients to every part of the heart muscle. Coronary stenosis develops when atherosclerotic plaques—deposits of cholesterol, fat, calcium, and inflammatory cells—accumulate within the arterial walls. Over decades, these plaques grow larger, progressively narrowing the vessel lumen (the inner space through which blood flows).
The severity of stenosis is expressed as a percentage of the vessel diameter that is obstructed. Mild stenosis (less than 50% narrowing) usually doesn’t restrict blood flow enough to cause symptoms. Moderate stenosis (50-70% narrowing) may cause symptoms during significant exertion. Severe stenosis (70-90% narrowing) typically produces symptoms with minimal exertion or even at rest. Critical stenosis (over 90% narrowing) causes severe symptoms and carries high risk of complete blockage. The location of stenosis is also clinically important—blockage of the LAD, particularly the proximal LAD, is especially serious because it supplies a large portion of the left ventricle. Risk factors are identical to those for atherosclerosis: age, male gender (men develop disease earlier), family history, high LDL cholesterol, low HDL cholesterol, hypertension, diabetes, smoking, obesity, sedentary lifestyle, unhealthy diet, chronic stress, and inflammatory conditions. While most coronary stenosis develops gradually over decades, some individuals experience rapid progression, particularly those with diabetes, poorly controlled risk factors, or genetic predisposition.
Important to Know
The hallmark symptom of significant coronary stenosis is angina—chest discomfort typically described as pressure, tightness, heaviness, or squeezing in the center or left side of the chest. Angina may radiate to the arms (especially left), shoulders, neck, jaw, or back. Classic “stable angina” occurs predictably with exertion or emotional stress and is relieved by rest or nitroglycerin within minutes. Other symptoms include shortness of breath with exertion or at rest, unusual fatigue or weakness, nausea, sweating, lightheadedness, and palpitations. Some individuals, particularly women, elderly patients, and diabetics, may experience “atypical” symptoms such as indigestion-like discomfort, unexplained fatigue, or subtle shortness of breath without classic chest pain. Silent ischemia—reduced blood flow without symptoms—can also occur. Complete or near-complete blockage causes myocardial infarction (heart attack) with symptoms including severe, crushing chest pain lasting more than a few minutes, shortness of breath, cold sweat, nausea or vomiting, and sense of impending doom. Diagnosis involves multiple approaches: non-invasive stress testing (exercise EKG, nuclear stress test, or stress echocardiography) to detect reduced blood flow during exertion; coronary CT angiography (CCTA), a non-invasive scan providing detailed images of coronary arteries and stenosis; and invasive coronary angiography (cardiac catheterization), the gold standard where contrast dye is injected directly into coronary arteries during real-time X-ray imaging, allowing precise measurement of stenosis severity. Treatment depends on stenosis severity, symptoms, and overall cardiac risk. Medical management includes antiplatelet agents (aspirin, clopidogrel) to prevent clot formation, statins to lower cholesterol and stabilize plaques, beta-blockers to reduce heart rate and oxygen demand, ACE inhibitors or ARBs for blood pressure control and cardiac protection, nitrates for angina symptom relief, and calcium channel blockers in select patients. Lifestyle modifications are essential: smoking cessation, heart-healthy diet (Mediterranean diet), regular exercise (as tolerated and cleared by physician), weight management, stress reduction, and diabetes control. Revascularization procedures restore blood flow: percutaneous coronary intervention (PCI or angioplasty) where a balloon-tipped catheter is threaded to the stenosis, inflated to compress the plaque, and a metal stent is placed to hold the artery open; and coronary artery bypass grafting (CABG), open-heart surgery creating new routes around blocked arteries using vessels from elsewhere in the body, typically reserved for severe multi-vessel disease or left main stenosis. Prognosis varies widely based on stenosis severity, number of vessels involved, left ventricular function, completeness of revascularization, and risk factor control. With appropriate treatment, many patients with coronary stenosis live active, productive lives. However, coronary stenosis is a chronic condition requiring lifelong management, medication adherence, regular follow-up, and sustained lifestyle modifications to prevent disease progression and reduce event risk.