Causes of Angina
Angina attacks are triggered by a reduced supply of oxygen-rich blood to the heart for a short period of time. There are three types of angina (stable, unstable, and variant), each with different causes and treatment options. The main angina causes are associated with coronary artery disease, but other factors, such as high blood pressure, can also trigger an attack.
What Causes Angina?
Angina pectoris, or angina for short, is caused by a temporary lack of oxygen-rich blood to the heart muscle. This decrease in blood flow can happen for a number of reasons, and will vary based on the type of angina. The most common cause of angina is coronary artery disease (CAD), or what most people refer to as just heart disease. Sometimes, other types of heart disease (such as aortic stenosis) or uncontrolled high blood pressure can cause this condition. There are also a number of factors that can trigger an angina attack.
Understanding Blood Flow to the Heart
In order to understand angina causes, it is often helpful to understand the heart and the coronary arteries. Like any muscle, the heart needs a constant supply of oxygen and nutrients, which are carried to it by the blood in the coronary arteries. Similar to other muscles, the harder the heart is working, the more oxygen and nutrients it needs. However, the coronary arteries can become narrowed or clogged, which can decrease the amount of blood that goes to the heart muscle. When the coronary arteries cannot supply enough oxygen-rich blood to the heart, angina symptoms can occur.
Causes of Angina: Coronary Artery Disease
The most common cause of angina is coronary artery disease. In coronary artery disease, the coronary arteries that carry oxygen-rich blood to the heart muscle are narrowed due to the buildup of fatty deposits called plaque. This is a condition called atherosclerosis. Some plaque is hard and stable, and leads to narrowed and hardened arteries; other plaque is soft and is more likely to break open and cause blood clots. The buildup of plaque on the inner walls of the arteries can cause angina by:
- Narrowing the artery to the point where the flow of blood is greatly reduced
- Forming blood clots that partially or totally block the artery.
Narrowing of the arteries usually results in stable angina symptoms. Unstable angina is usually caused by a blood clot that blocks the artery.