coronary artery disease
Meaning of coronary artery disease: Narrowing causes symptoms during exertion, but it is a plaque that suddenly ruptures which causes most heart attacks.
Definition of coronary artery disease
Coronary artery disease is narrowing or blockage of the coronary arteries, the vessels supplying oxygen-rich blood to the heart muscle itself. It develops as atherosclerosis, a build-up of fatty plaque within the artery wall, gradually reduces the space available for blood to flow. The condition is also called coronary heart disease and abbreviated CAD.
How does the narrowing develop?
Atherosclerosis begins with injury to the thin lining of the artery, inflicted across years by raised blood pressure, circulating LDL cholesterol, tobacco smoke and high blood sugar. LDL particles enter the wall at the damaged point, are chemically altered there, and draw in immune cells that engulf them and become foam cells. The accumulating mass of fat, cells and debris forms a plaque inside the wall, covered by a fibrous cap. Early on the artery enlarges outward to accommodate the plaque, so the channel stays open and nothing is felt. Only as the plaque grows further does the channel narrow enough to limit flow.
What does reduced flow cause?
Heart muscle already extracts a large share of the oxygen from the blood reaching it at rest, so it cannot compensate for a poor supply by taking more. It depends instead on flow increasing during exertion. A narrowed artery can deliver enough at rest but not enough during effort, and the shortfall causes angina: chest pressure or tightness during exertion or emotional stress that eases within minutes of stopping. Breathlessness may accompany it or replace it. Presentations are not always typical, and pain felt in the jaw, arm, back or upper abdomen, or breathlessness and fatigue with no chest pain at all, occur often enough that their absence does not rule the disease out.
What causes a heart attack?
| Stable narrowing | Plaque rupture | |
|---|---|---|
| What happens | Flow limited by a fixed narrowing | The fibrous cap tears and a blood clot forms on it |
| Timing | Predictable, brought on by exertion | Sudden, often at rest |
| Result | Angina that eases with rest | Abrupt blockage and death of heart muscle |
| Size of the plaque | Usually substantial | Often modest before it ruptures |
The plaque most likely to rupture is not necessarily the largest, which is why a heart attack can be the first sign of disease in someone who never experienced angina. Established risk factors include smoking, high blood pressure, raised cholesterol, diabetes, physical inactivity, obesity and a family history of the disease appearing early in a close relative. Management ranges from addressing those risk factors and using medication through to opening the artery with a stent or routing blood around the blockage, as in a coronary artery bypass.
Also known as
Used in a sentence
Cardiac catheterization confirmed significant coronary artery disease requiring further intervention.
Good to know
Coronary artery disease describes the underlying narrowing of the vessels, whereas a heart attack refers to the acute event occurring when blood flow through a narrowed or blocked artery is suddenly and severely interrupted.
Word origin
Where “coronary artery disease” comes from
Coronary, from Latin corona, meaning crown, describes the arteries' crown-like encirclement of the heart, the structure to which the disease refers.