What is coronary artery disease?
Coronary artery disease — sometimes called CAD or ischaemic heart disease — is the most common form of heart disease, and the leading cause of heart attacks worldwide. It develops when the arteries that supply blood to the heart become narrowed or hardened, reducing the amount of oxygen-rich blood that can reach the heart muscle.
It is a condition that builds silently over many years, often without any warning signs — until a heart attack or other cardiac event makes it impossible to ignore.
What causes it?
Coronary artery disease is caused by a process called atherosclerosis — the gradual build-up of fatty deposits, known as plaque, inside the walls of the coronary arteries. Plaque is made up of cholesterol, fat, calcium, inflammatory cells and other substances that accumulate over time.
As plaque builds up, it narrows the artery and reduces blood flow. The artery wall also becomes less flexible and more prone to damage. If a piece of plaque ruptures, the body responds by forming a blood clot at the site — and it is this clot that can block the artery entirely and trigger a heart attack.
Atherosclerosis doesn't only affect the heart. The same process can occur in arteries throughout the body, contributing to stroke, peripheral artery disease and other conditions.
What are the risk factors?
The risk factors for coronary artery disease are closely linked to those for heart attack and cardiovascular disease more broadly. They include high blood pressure, high LDL ("bad") cholesterol, type 2 diabetes, smoking, physical inactivity, carrying excess weight, a family history of heart disease, older age and being male. Chronic inflammation — increasingly understood as a key driver of plaque development — is also a significant factor.
Having one risk factor raises your risk. Having several compounds it considerably. Importantly, many of the most powerful risk factors are modifiable.
What are the symptoms?
Many people with coronary artery disease have no symptoms at all for years. When symptoms do appear, the most common is angina — a feeling of chest tightness, pressure, heaviness or pain, often triggered by physical exertion or stress and relieved by rest. Angina occurs when the heart muscle isn't receiving enough blood to meet its demands.
Other symptoms can include shortness of breath, fatigue and, in some cases, palpitations. For some people, the first sign of coronary artery disease is a heart attack.
How is it diagnosed?
Coronary artery disease can be diagnosed through a range of tests depending on symptoms and risk level. These include electrocardiograms (ECGs), exercise stress tests, coronary CT angiography — which creates detailed images of the coronary arteries — and invasive coronary angiography, where dye is injected into the arteries to identify blockages.
Blood tests measuring cholesterol, blood sugar and markers of inflammation also form part of risk assessment.
How is it treated?
Treatment for coronary artery disease typically involves a combination of lifestyle changes, medication and, in some cases, procedures to restore blood flow.
Lifestyle changes — including eating a heart-healthy diet, being physically active, not smoking and managing weight — remain central to both prevention and management.
Medications commonly used include statins to lower cholesterol, blood pressure medications, antiplatelet drugs to reduce clotting risk and, where appropriate, newer agents that target specific pathways in cardiovascular disease.
When blockages are significant, procedures such as percutaneous coronary intervention (PCI, or angioplasty) — where a balloon and stent are used to open a narrowed artery — or coronary artery bypass grafting (CABG) surgery may be recommended.