Atherosclerosis is a condition where the arteries become narrowed and hardened due to a buildup of plaque around the artery wall. This plaque is usually made up of fat, cholesterol, calcium, and other substances found in the blood. Over time, this buildup causes the arteries to become less flexible, restricting blood flow or even blocking it altogether.

The process of atherosclerosis begins with damage to the endothelium, the inner lining of the artery. This damage can be caused by factors such as high blood pressure, smoking, high cholesterol, or diabetes. Once the endothelium is damaged, cholesterol and other substances in the blood start to accumulate at the site, leading to the formation of plaque.

As the plaque grows, it can lead to several serious health problems, including:

1. Coronary Artery Disease (CAD): This occurs when the coronary arteries become affected by atherosclerosis. Reduced blood flow to the heart can cause chest pain (angina) and other symptoms of heart disease, and a complete blockage can cause a heart attack.
2. Carotid Artery Disease: When atherosclerosis affects the arteries in the neck, which supply blood to the brain, it can lead to symptoms like transient ischemic attacks (TIAs) or strokes.
3. Peripheral Artery Disease (PAD): This happens when atherosclerosis affects the arteries that supply blood to the limbs, particularly the legs, leading to pain and fatigue in the affected limbs.
4. Chronic Kidney Disease: Atherosclerosis can also affect the renal arteries and impair kidney function over time.

Risk factors for atherosclerosis include unhealthy diet, lack of exercise, smoking, obesity, high blood pressure, high cholesterol levels, age, and a family history of early heart disease. Lifestyle changes and medications are typically used to manage and treat atherosclerosis, aiming to reduce the risk factors and prevent the progression of the disease.