Coronary Artery Disease (CAD)

How coronary artery disease develops

Three main coronary arteries run over the surface of the heart, supplying its muscle with oxygen-rich blood. In CAD, cholesterol and inflammatory cells collect in the artery wall over years, forming plaques (atherosclerosis).

• Stable plaques gradually narrow the artery. At rest, enough blood gets through. During exercise or stress, the heart needs more oxygen than the narrowed artery can supply, causing angina.
• Unstable plaques can crack. A blood clot forms over the crack and can suddenly block the artery, causing acute coronary syndrome: unstable angina or a heart attack.

Many heart attacks come from plaques that were not severely narrowing the artery beforehand, which is why preventive treatment matters even when symptoms are mild.

Symptoms

Stable angina

• Pressure, tightness, squeezing, heaviness or burning in the center of the chest
• May spread to the arms (often the left), neck, jaw, back or upper belly
• Brought on by exertion, cold weather, heavy meals or emotional stress
• Lasts a few minutes and eases with rest or nitroglycerin

Other symptoms

• Shortness of breath with exertion
• Unusual tiredness
• Palpitations
• Some people, especially those with diabetes, older adults and women, have breathlessness, fatigue, nausea or indigestion-like discomfort rather than classic chest pain. CAD can also be "silent."

Heart attack symptoms

Chest pain or pressure lasting more than a few minutes, often with sweating, nausea, breathlessness, lightheadedness and anxiety. This is an emergency.

Risk factors

Diagnosis

• History and examination, including the type and triggers of chest pain and risk factors.
• Blood tests: cholesterol, blood sugar or HbA1c, kidney function. Troponin if a heart attack is suspected.
• ECG: may be normal at rest, or show signs of previous heart attack or strain.
• Stress testing: exercise ECG, stress echocardiogram, or nuclear perfusion scan, which show whether parts of the heart get too little blood during exertion.
• CT coronary angiography: a contrast CT scan that shows plaque and narrowing. Often a first-line test for chest pain.
• Coronary artery calcium score: a CT scan without contrast to measure calcified plaque, used to refine risk in people without symptoms.
• Invasive coronary angiography (cardiac catheterization): dye injected through a catheter shows blockages in detail, and stents can be placed at the same time.
• Echocardiogram: shows how well the heart pumps.

Treatment

Lifestyle

• Stop smoking: this sharply reduces the risk of heart attack.
• Heart-healthy eating: vegetables, fruit, whole grains, legumes, nuts, fish and olive oil. Limit salt, saturated fat, processed meat and added sugar.
• Regular exercise: at least 150 minutes a week of moderate activity, as advised by your doctor.
• Weight management, limiting alcohol, good sleep and stress management.
• Cardiac rehabilitation after a heart attack or procedure.

Medicines

• Statins and other cholesterol-lowering medicines (ezetimibe, PCSK9 inhibitors) to stabilize plaque and lower risk.
• Antiplatelet medicines such as aspirin, and after stents, a second antiplatelet drug for a period.
• Beta blockers and calcium channel blockers to reduce angina.
• Nitrates: short-acting nitroglycerin spray or tablets for angina attacks, and long-acting forms for prevention. Do not combine with erectile dysfunction medicines such as sildenafil.
• Ranolazine for persistent angina.
• ACE inhibitors or ARBs, especially with high blood pressure, diabetes, kidney disease or a weak heart.
• Diabetes medicines with proven heart benefits (SGLT2 inhibitors and GLP-1 receptor agonists) for people with diabetes.

Procedures

• Percutaneous coronary intervention (PCI): a balloon opens the narrowed artery and a stent keeps it open. It is the main emergency treatment for heart attacks. In stable CAD, it mainly relieves symptoms when medicines are not enough.
• Coronary artery bypass grafting (CABG): surgery using veins or arteries to bypass blockages. Often recommended for disease in several arteries, the left main artery, or with diabetes.

Complications

• Heart attack
• Heart failure from damaged heart muscle
• Arrhythmias, including atrial fibrillation and dangerous ventricular rhythms
• Sudden cardiac death

Outlook

CAD is a lifelong condition, but outcomes have improved greatly. With risk factor control, medicines and procedures when needed, many people live for decades with good quality of life. Taking medicines consistently, stopping smoking and staying active are the most important factors you control.

How CAD fits into cardiovascular disease

CAD is the most common form of cardiovascular disease, which also includes stroke, peripheral artery disease and other conditions caused by the same plaque process. Having CAD raises your risk of these too, and the same treatments help prevent them.

Frequently asked questions

What are the symptoms of coronary artery disease?

The main symptom is angina: pressure, tightness or heaviness in the chest during exertion or stress that eases with rest, sometimes spreading to the arm, jaw or back. Breathlessness and tiredness are also common. Some people, especially those with diabetes, have few or no symptoms until a heart attack.

What causes coronary artery disease?

CAD is caused by atherosclerosis, a buildup of cholesterol and inflammatory cells in the walls of the coronary arteries. High LDL cholesterol, high blood pressure, smoking, diabetes, obesity, inactivity, unhealthy diet and family history all speed up plaque formation.

Can coronary artery disease be reversed?

Plaque does not usually disappear, but intensive treatment can stabilize it and, in some studies, slightly reduce its size. High-intensity statins, stopping smoking, a heart-healthy diet, exercise and blood pressure control greatly lower the risk of heart attack and can relieve symptoms.

How is coronary artery disease diagnosed?

Doctors use the history, ECG and blood tests, followed by stress tests or CT coronary angiography to look for reduced blood flow or narrowed arteries. Invasive coronary angiography gives the most detailed view and allows stenting during the same procedure.

What is the difference between coronary artery disease and a heart attack?

Coronary artery disease is the long-term narrowing of heart arteries by plaque. A heart attack is a sudden event in which an artery becomes blocked, usually by a clot on a ruptured plaque, damaging heart muscle. CAD is the underlying condition that leads to most heart attacks.