Atherosclerotic cardiovascular disease (ASCVD) refers to conditions caused by atherosclerosis, a process where a substance called plaque builds up inside the arteries. This buildup, composed of fats, cholesterol, and calcium, thickens and hardens the artery walls. Over time, this process narrows the arteries, restricting the flow of oxygen-rich blood to organs. ASCVD is the primary underlying cause of cardiovascular disease globally.
The Process of Atherosclerosis
The development of atherosclerosis is a slow, progressive disease that can begin in childhood and advances with age. The process starts with damage to the endothelium, the thin inner lining of an artery. This initial injury can be caused by various factors, including high cholesterol and high blood pressure.
When LDL cholesterol crosses the damaged endothelium, it becomes oxidized and triggers an inflammatory response. The body sends white blood cells (monocytes) to the injury site. These monocytes transform into macrophages that consume the oxidized LDL, and as they become engorged, they are termed “foam cells” due to their appearance.
This accumulation of foam cells forms a fatty streak, an early visible sign of atherosclerosis. Over years, these fatty streaks evolve into more complex plaques. Smooth muscle cells migrate and multiply, forming a fibrous cap over the site. This structure, the atherosclerotic plaque, narrows the artery and can either remain stable or become prone to rupture.
Key Risk Factors for Development
The factors contributing to atherosclerosis fall into two categories. Non-modifiable risk factors are ones you cannot control, such as age, sex, and family history. The risk of atherosclerosis increases as people get older, and men are generally at a higher risk than women until later in life. A family history of premature heart disease also increases an individual’s risk.
Modifiable risk factors are those that can be managed through lifestyle changes or medical treatment. High blood pressure places mechanical stress on the artery walls, promoting endothelial damage. High levels of LDL cholesterol in the blood provide the material for plaque formation. Other factors include:
- Tobacco use, which damages the endothelium and promotes plaque development.
- Diabetes, which accelerates atherosclerosis by creating a pro-inflammatory state.
- Obesity.
- An unhealthy diet and lack of physical activity.
- Excessive alcohol consumption.
Conditions Caused by Atherosclerosis
Atherosclerosis causes clinical diseases when plaque buildup severely narrows an artery or when a plaque ruptures, leading to a blood clot. The specific condition that develops depends on the location of the affected arteries.
When atherosclerosis affects the arteries supplying the heart, it is called coronary artery disease (CAD). The narrowing of these arteries can cause chest pain (angina), especially during physical activity. If a plaque ruptures and a clot completely blocks blood flow, it results in a myocardial infarction, or heart attack.
In arteries leading to the brain, atherosclerosis causes cerebrovascular disease. A temporary blockage can lead to a transient ischemic attack (TIA), which causes stroke-like symptoms but no permanent brain injury. If a blood clot causes a prolonged blockage, it results in an ischemic stroke, depriving brain tissue of oxygen and leading to cell death.
Atherosclerosis in the arteries of the limbs, most commonly the legs, is called peripheral artery disease (PAD). Reduced blood flow to the leg muscles can cause pain and cramping during physical activity, a symptom called claudication. In severe cases, PAD can lead to constant pain, non-healing sores, or tissue death (gangrene).
Diagnosis and Treatment Approaches
Diagnosing ASCVD involves a physical exam, family history review, and various tests. Blood tests are used to check levels of cholesterol and blood sugar. An electrocardiogram (ECG) measures the heart’s electrical activity to detect poor blood flow, while imaging tests like a CT scan or angiogram can identify blockages.
Treatment for ASCVD focuses on slowing the progression of atherosclerosis and managing symptoms to prevent major events like a heart attack or stroke.
Lifestyle Changes
These changes include adopting a heart-healthy diet low in saturated fats, engaging in regular physical exercise, quitting smoking, and maintaining a healthy weight.
Medications
Medications are often prescribed to manage underlying risk factors. Statins are widely used to lower LDL cholesterol, and other drugs may be used to control high blood pressure or manage diabetes. Antiplatelet medications, like aspirin, can help prevent the formation of blood clots.
Surgical Procedures
For severe blockages, more invasive procedures may be necessary. Angioplasty involves inserting a catheter with a balloon to open the narrowed artery, often followed by the placement of a stent to keep it open. In cases of extensive blockages, bypass surgery is performed to create a new path for blood flow around the blocked artery.