What are the signs and symptoms of atherosclerosis?

What is atherosclerosis?
Atherosclerosis is a condition that develops when fats, cholesterol, calcium, and other substances build up in and on the artery walls. This plaque formation narrows the arteries, making it harder for oxygen-rich blood to flow through. When an area of plaque ruptures, platelets can stick to the site of injury and form a blood clot, which further narrows the artery. In addition, this blood clot may break free and cause a blockage elsewhere in the body.

What causes atherosclerosis?
Atherosclerosis is caused by elevated cholesterol levels, particularly high levels of LDL cholesterol. LDL cholesterol is known as “bad” cholesterol, as it is the cholesterol carried by LDL particles and tends to get deposited around the body. In contrast, HDL cholesterol is considered “good” cholesterol, as the HDL particles collect cholesterol from around the body and deliver it to the body for recycling or excretion.

There are many factors that can contribute to elevated LDL cholesterol levels. People with certain genotypes have an increased risk, males generally have higher levels than females, and older people tend to have higher levels. Other contributing factors include excess alcohol consumption, a high-fat diet, low physical activity, and being overweight or obese.

Early changes from atherosclerosis
Sometimes the early atherosclerotic changes are called “silent” symptoms, as they often do undetected. High cholesterol levels can result in fatty deposits building up in the blood vessels, resulting in the formation of plaques that damage and decrease the diameter of the blood vessels. These plaques cause hardening of the arteries and blood clots often form in these narrowed blood vessels.

Painful symptoms
Atherosclerosis can severely decrease blood flow to certain tissues, and this is when individuals start to feel the effects of high cholesterol levels. Peripheral vascular disease occurs when a blood vessel is severely restricted in an arm, leg, or organs below the stomach. This causes extreme pain and cramping in the affected area, and can lead to ulcers, gangrene, and other infections. If the blood flow restriction occurs in the chest area, angina (chest pain) occurs. This pain is felt as a squeezing, suffocating, or burning feeling. Although angina is not a heart attack, it is a warning sign of an increased risk of a heart attack, and immediate medical attention should be received.

Serious symptoms
If atherosclerosis and associated blood clot occur in one of the blood vessels in the heart, the blood flow can be completely blocked. This is what occurs during a myocardial infarction (heart attack). The heart tissue usually supplied by the blocked blood vessel suddenly loses its blood and oxygen supply and can quickly die if the blockage is not removed. The severity of the heart attack depends on which blood vessel has been blocked. If the blockage occurs in a main coronary artery, a large area of heart tissue will be affected and a more serious heart attack occurs, with more severe consequences. If a smaller artery is blocked, less tissue damage occurs and the expected recovery is less complicated.

Heart attacks require immediate medical attention and no one should “tough out” a heart attack. The most common symptom of a heart attack is chest pain, which may extend to other upper body areas (shoulders, arms, back, neck, etc.). Some people experience severe unexplained pain in the upper body but do not actually experience any chest pain. Other symptoms include stomach pain, nausea, shortness of breath, anxiety, sweating, and dizziness. Often the symptoms are only mild to start, but if there is any suspicion of a heart attack, immediate medical attention is essential to minimize further complications.

If a blood vessel within the brain or supplying blood to the brain is blocked due to atherosclerosis and a blood clot, an atherothrombotic stroke occurs. Alternatively, a piece of plaque or blood clot can break loose from an atherosclerotic vessel in another part of the body and travel to the brain, and cause a blockage in a blood vessel in the brain. This is known as a cerebral embolism. Both stroke types result in the death of brain tissue in the regions lacking blood and oxygen supply due to the blood vessel blockage. Further brain damage (often after the stroke has occurred) can also occur due to the excessive accumulation of fluid in the brain, known as cerebral edema.

Immediate medical attention is essential for any indications of a stroke. The signs of a stroke occur very suddenly. They include numbness or weakness in the face or body, (especially on one side), confusion and trouble understanding or speaking, difficulty seeing out of one or both eyes, dizziness, loss of balance, and a severe headache. Not everyone will suffer from all of these symptoms, but if there is any possibility of a stroke, immediate medical attention must be received.

References:
1. Mozaffarian D, Benjamin EJ, Go AS, et al. (2015). Heart disease and stroke statistics—2015 update: a report from the American Heart Association. Circulation. 131: e29-322.
2. What is Cardiovascular Disease? American Heart Association.
3. Heart Disease in Women. National Heart, Lung and Blood Institute