Atherosclerosis is a chronic, inflammatory disease of the arterial wall. It is a dynamic natural process that affects medium and large-sized arteries.
Cardiovascular disease is a major cause of mortality and morbidity in western countries and soon will be the leading cause of death worldwide. This is due to the increasing prevalence of risk factors such as diabetes and obesity.
The main cause of cardiovascular disease is atherosclerosis, a chronic inflammation initiated by hyperlipidemia and characterized by the development of lipid-rich plaques on the inner walls of the arteries. These plaques are made up of cholesterol (LDL cholesterol), calcium, fat, fibrin, and other substances.
The smaller particles of the LDL cholesterol get oxidized when they react with the free radicals. This oxidized cholesterol triggers an inflammation process that attracts the white blood cells (WBCs) called macrophages. This happens because the WBCs of our immune system function to fight inflammation and infection.
The WBCs surround the oxidized LDL forming new fat cells, which bunch together, stick to the inner walls of the arteries, and form atherosclerotic plaques.
Atherosclerosis is a slowly progressive disease, these plaques grow, and over time can cause your arteries to narrow and block blood flow to the organ of supply. The plaque can also get dislodged and form a blood clot leading to thrombotic occlusion of the overlying artery. Atherosclerosis can begin as early as childhood.
As wrongly believed, atherosclerosis is not just a heart problem; it can affect any artery in your body. While atherosclerosis of the coronary arteries is more common in men, atherosclerosis of the cerebral arteries is equally common in both sexes.
The main critical conditions caused by this condition are a heart attack, stroke, peripheral vascular disease, and kidney problems depending on which arteries are badly affected. However, if detected early, these conditions can be prevented and atherosclerosis can be treated.
Atherosclerosis is considered a specific type of arteriosclerosis in which the blood vessels become thick and stiff and restrict the flow of blood to your organs and tissues
Symptoms of atherosclerosis
Mild atherosclerosis usually does not have any symptoms. Atherosclerosis symptoms present when an artery is narrowed or clogged to the extent that it cannot supply enough blood to its organ of supply.
Even when a plaque ruptures, you may not have symptoms until the clot has caused significant narrowing or occlusion of an artery.
Your symptoms may start when the lumen of your artery is blocked to the tune of 70% or more. This amount of blockage significantly impedes blood flow and oxygen supply to an organ or tissue causing symptoms to present.
Symptomatic atherosclerosis is typically associated with men in their 40s and women in their 50s to 60s.
Many people don’t even know they have this condition until they experience its complication such as a heart attack or stroke.
Symptoms of moderate to severe atherosclerosis depend on the arteries that are significantly narrowed by atherosclerotic plaques.
If you have developed atherosclerosis in your heart arteries, you may have symptoms of a heart attack, which may set in days, weeks, or even months before the heart attack.
Symptoms of atherosclerosis of coronary arteries include
Chest pain can initially only come after exercising due to angina and later due to a heart attack.
- The chest pain may be mild discomfort or severe, crushing pain.
- It may radiate to one or both arms or shoulders.
- There may be discomfort in your neck or jaw.
- You could experience nausea or vomiting.
- You could have palpitations
- There are may be anxiety, sweating, or dizziness.
- Women may also experience shortness of breath, fatigue, and insomnia.
Symptoms of atherosclerosis of carotid arteries.
Carotid arteries supply blood to the brain and neck. Their blockage causes symptoms related to stroke, which is caused by marked narrowing or occlusion of arteries supplying blood and oxygen to the brain. Symptoms of atherosclerosis in arteries of the brain:
- Difficulty in concentrating
- Slurred speech
- Difficulty in walking or standing up straight
- Blurred vision or temporary loss of vision in one eye
- Numbness of one side of the face, arms, and legs
- Drooping muscles in your face
- Severe headache
- Loss of consciousness
Initially, a transient ischemic attack (TIA) can also present with these symptoms, which if left untreated, may progress to a stroke.
Symptoms of atherosclerosis in peripheral arteries of limbs
If you have developed atherosclerosis in the arteries of your arms and legs, you may have symptoms and signs of peripheral artery disease (PAD). These include
- Painful cramps in one or both the hips, thighs, or calf muscles after walking or climbing stairs
- There may be pain in the leg when walking (claudication pain)
- Decreased blood pressure in the affected limb
- The leg or foot of the affected side may feel cold when compared with the other side.
- You may develop sores on your toes, foot, or leg of the affected side that won’t heal.
Symptoms and signs of atherosclerosis in the arteries leading to your kidneys include:
- High blood pressure
- Kidney failure, which will be treated with dialysis or a kidney transplant
- Swollen ankles or feet due to fluid retention
- Shortness of breath due to pulmonary edema (a sudden buildup of fluid in the lungs)
What causes atherosclerosis?
It’s not clear exactly what causes atherosclerosis or what initiates it. It is believed to be due to multiple factors.
Atherosclerosis is a slow, progressive disease that may begin as early as childhood. There is a gradual buildup of plaque and thickening caused by inflammation that develops on the inner side of the walls of the arteries. This interferes with the supply of blood and oxygen to the vital body organs and extremities.
Atherosclerosis may start with damage to the inner layer of an arterial wall (endothelium). This damage develops gradually and occurs over time. The damage may be caused by multiple risk factors that are described below:
Once the inner wall of an artery is damaged, blood cells, cholesterol, and other substances adhere and accumulate at the injury site and form a plaque, which can harden and narrow the lumen of the arteries.
This disrupts the blood supply to the organs and tissues supplied by the blocked arteries, which then are not able to function properly.
Eventually, pieces of the fatty plaques may get dislodged and enter your bloodstream. This may cause a blood clot, which can occlude the artery and block the blood flow to a specific part of your body, such as your heart causing a heart attack.
Similarly, the blood clot can travel to any other part of your body and block blood flow to another organ.
Factors that may increase your risk of atherosclerosis include:
- High blood pressure. In people with higher blood pressure, the arteries swell and stretch more than normal with each heartbeat. This can damage the endothelium, the delicate inner lining of all arteries, which can cause the arteries to become stiffer over time.
- High cholesterol. If your LDL cholesterol blood levels are too high, it can get deposited up on the inner walls of your arteries. Over time, this deposit can build up and form a plaque.
- High triglycerides. The lipoprotein particles that carry triglycerides (VLDL) in the bloodstream may deposit in the heart arteries in a manner similar to LDL.
- Smoking. Cigarette smoking is widely accepted as a major risk factor for the development of atherosclerosis. The toxins in tobacco smoke damage the inner walls of the arteries, which makes it easier for cholesterol and other substances to deposit on the arterial walls.
- Obesity. Obesity is a well-known risk factor for atherosclerosis and accelerates its formation by causing an increase in blood pressure, glucose level, lipid profiles, and systemic inflammation.
- Diabetes. Diabetes causes metabolic abnormalities including vascular dysfunction, inflammation, hemostasis, and alterations at the cellular level of vascular tissue, which significantly accelerates atherosclerosis.
- A family history of early heart disease. Family history is one of the biggest risk factors for atherosclerosis. Your risk increases significantly if your immediate male relatives (father or brother) were diagnosed before age 55, or if your immediate female relatives (mother or sister) were diagnosed before age 65 years.
- Lack of exercise. Inactivity contributes to endothelial dysfunction and atherosclerosis in people with a sedentary lifestyle. It ranks similarly to cigarette smoking, high blood pressure, and elevated cholesterol as risk factors.
- Advanced age. As you age, your arteries stiffen and lose elasticity making them more vulnerable to plaque buildup.
Among the above, cigarette smoking and a rich-fat diet (saturated fat) are the most risky factors that make you prone to developing atherosclerosis.
Complications of atherosclerosis
The complications of atherosclerosis include:
- Coronary artery disease. When the coronary arteries of the heart develop atherosclerosis, you may develop complications of coronary artery disease, such as heart attack (angina) or heart failure.
- Carotid artery disease. When atherosclerosis affects the carotid arteries that carry blood to the brain, you may develop a transient ischemic attack (TIA) or stroke.
- Peripheral artery disease. When atherosclerosis narrows the peripheral arteries in your arms or legs, blood circulation in your arms and legs will be affected causing complications of peripheral artery disease. There will be a loss of sensation to hot and cold, increasing your risk of burns or frostbite. In severe cases, poor circulation in your arms or legs can lead to tissue death (gangrene).
- Aneurysms. An aneurysm is a serious complication that can occur in any big artery in your body. An aneurysm is a bulge formed in the wall of your artery. Usually, there are no symptoms. The aneurysm may rupture causing pain and this is a medical emergency because of the internal bleeding.
- Chronic kidney disease. Atherosclerosis can cause narrowing of the renal arteries of the kidneys affecting the supply of blood and oxygen to them. Over time, kidney function will be affected.