Coronary Artery Disease

What it is

Coronary artery disease is narrowing or blockage of the heart’s arteries by plaque; in 2022 it caused 371,506 deaths in the U.S. It is also called CAD, coronary heart disease, or ischemic heart disease. The core problem is atherosclerosis, a process in which cholesterol, inflammatory cells, and fibrous material build up in the coronary arteries and reduce blood flow to the heart muscle. When the heart does not get enough oxygen-rich blood, it can cause chest pain called angina, shortness of breath, reduced exercise tolerance, heart attack, heart failure, abnormal heart rhythms, or sudden cardiac death.

CAD can be silent for years. In some people, the first sign is a heart attack rather than warning symptoms. CAD is one of the leading causes of illness and death worldwide, and it is strongly linked to smoking, diabetes, high blood pressure, abnormal cholesterol levels, obesity, physical inactivity, kidney disease, and family history of early heart disease. In India, ischemic heart disease is a major contributor to premature death, and risk often appears at younger ages than in many Western populations, partly because of high rates of diabetes, central obesity, and dyslipidemia.

A simple way to think about CAD is:

Term	Meaning
Stable angina	Predictable chest discomfort with exertion or stress
Acute coronary syndrome	Sudden reduction in blood flow, including unstable angina and heart attack
Silent ischemia	Reduced blood flow without obvious symptoms

How it works

CAD usually begins with injury and dysfunction in the inner lining of arteries, called the endothelium. Over time, low-density lipoprotein cholesterol enters the artery wall, becomes oxidized, and triggers inflammation. Immune cells, smooth muscle cells, and fibrous tissue then form plaque. Some plaques gradually narrow the artery and limit blood flow during exertion. Others are less obstructive but unstable, and if they rupture, a blood clot can form quickly and suddenly block the artery.

This is why a person with only moderate narrowing can still have a heart attack. The danger is not only how narrow the artery looks, but also whether the plaque is inflamed and prone to rupture.

Common risk factors include:

1. Smoking or tobacco exposure
2. High LDL cholesterol or low HDL cholesterol
3. High blood pressure
4. Diabetes or insulin resistance
5. Older age and male sex, though women are also affected and may have atypical symptoms
6. Family history of premature CAD
7. Chronic kidney disease, inflammatory disorders, obesity, poor sleep, and physical inactivity

In South Asian populations, including Indians, CAD risk can occur at lower body mass index values and with more abdominal fat, higher triglycerides, and earlier diabetes. That is one reason clinicians often pay close attention to waist circumference, blood sugar, and lipid patterns even when overall body weight does not seem very high.

Diagnosis / how it's measured

Diagnosis starts with symptoms, risk factors, physical examination, and basic tests. No single test fits every person. The choice depends on whether symptoms are stable or sudden, and on the estimated likelihood of CAD.

Common tests include:

Test	What it helps show
ECG/EKG	Heart rhythm changes, prior heart damage, or signs of active ischemia
Blood troponin	Heart muscle injury, especially in suspected heart attack
Echocardiogram	Pumping function and wall-motion abnormalities
Exercise stress test	Whether exertion triggers ischemia
Stress imaging	Reduced blood flow or abnormal contraction during stress
Coronary CT angiography	Noninvasive view of coronary narrowing and plaque
Invasive coronary angiography	Direct imaging of coronary blockages; can guide stenting

Blood pressure, fasting glucose or HbA1c, and a lipid profile are also important because they measure major drivers of CAD risk rather than the blockage itself. In some cases, clinicians use calcium scoring by CT to estimate plaque burden in people without known CAD but with uncertain risk.

Symptoms that raise concern include pressure, tightness, heaviness, or burning in the chest, especially with walking or climbing stairs; pain spreading to the arm, jaw, back, or upper abdomen; shortness of breath; sweating; nausea; and unexplained fatigue. Women, older adults, and people with diabetes may have less typical symptoms.

Evidence and uses

Treatment aims to do 2 things: reduce symptoms and lower the chance of heart attack, stroke, and death. The main evidence-based approaches are lifestyle change, medicines, and in selected cases procedures.

Lifestyle measures include stopping smoking, regular physical activity, weight management, good sleep, and a heart-healthy eating pattern that emphasizes vegetables, fruits, legumes, whole grains, nuts, and unsaturated fats while limiting trans fat, excess salt, and highly processed foods. In India, this often means improving the quality of common dietary patterns by reducing fried snacks, refined carbohydrates, excess ghee or vanaspati, and tobacco use, while increasing pulses, vegetables, and fiber-rich foods.

Medicines commonly used include:

Medicine class	Main role
Statins	Lower LDL cholesterol and reduce cardiovascular events
Antiplatelet drugs such as aspirin	Reduce clot formation in selected patients
Beta-blockers	Lower heart workload and help angina after heart attack
ACE inhibitors or ARBs	Help blood pressure control and protect high-risk patients
Nitroglycerin	Relieves angina symptoms
Other anti-anginal drugs	Used when symptoms persist or first-line drugs are not suitable

For some patients, revascularization improves symptoms and, in specific high-risk patterns, prognosis. The two main procedures are percutaneous coronary intervention, usually with a stent, and coronary artery bypass grafting. These are not substitutes for risk-factor control. Even after a stent or bypass, long-term medical therapy and lifestyle treatment remain essential.

When to see a clinician

Seek emergency care now for chest pressure, tightness, or pain lasting more than a few minutes, especially if it occurs at rest or comes with shortness of breath, sweating, nausea, fainting, or pain in the arm or jaw. A possible heart attack should not be watched at home.

Make a routine appointment if you have exertional chest discomfort, unusual breathlessness, declining exercise tolerance, erectile dysfunction with vascular risk factors, or major risk factors such as diabetes, smoking, high blood pressure, high cholesterol, or strong family history. People with known CAD need regular follow-up to review symptoms, blood pressure, cholesterol, diabetes control, and medication adherence.

Limitations and open questions

CAD is not always a simple problem of one large blockage. Some people have microvascular angina or coronary artery spasm, where symptoms occur despite no major obstruction on angiography. Standard tests may miss these patterns.

Risk prediction is also imperfect. A person can have few symptoms and still have dangerous plaque. Conversely, chest pain may come from causes other than CAD, including reflux, anxiety, lung disease, or musculoskeletal pain. This is why diagnosis depends on the full clinical picture rather than one symptom or one test.

Treatment evidence is strong for smoking cessation, statins, blood pressure control, diabetes management, and cardiac rehabilitation. But the best strategy for some groups, such as people with nonobstructive CAD, women with atypical symptoms, and patients with mixed plaque patterns, is still being refined. Research continues on inflammation, lipoprotein(a), imaging-guided prevention, and how to better identify high-risk plaque before it causes a heart attack.