Atherosclerosis is a condition wherein the walls of arteries become clogged with fats, cholesterol, and other substances, commonly known as plaque.
Normally, the flow of the blood through the arteries resembles the flow of water through a pipe. Over the time, the plaque build-up in the arteries hardens and narrows the arteries, which further limits the flow of oxygen-rich blood to the heart and other organs of the body.
Atherosclerosis restricts the blood flow through the artery. The most commonly affected arteries are the arteries of the heart (coronary arteries), arteries of the neck (carotid arteries) and arteries of the legs.
Sometimes, the accumulated plaque in the arterial wall can burst, leading to the formation of a blood clot (thrombus) which can further block the blood flow to the organs.
Atherosclerosis can lead to serious complications such as heart attack, stroke or even death. This disease normally starts early in life and many people have an accumulated plaque by the middle age. Most people do not present any symptoms until the artery is blocked by at least half.
Pathophysiology
Atherosclerosis may start in early childhood. The exact cause is not known, but atherosclerosis is believed to start when the inner lining of the artery gets damaged. This damage can result from high blood pressure, high levels of cholesterol and triglycerides (a type of fat) in the body, high levels of insulin in the blood, obesity, inflammation from diseases such as arthritis, lupus or infections and chemicals from smoking tobacco.
The blood vessel reacts to this injury by depositing plaque (made from fatty substances, cholesterol, calcium and other substances) on the inner lining of the artery. This makes the blood vessels narrower, making the blood flow harder. The organs and tissues connected to the blocked arteries do not receive enough blood to function properly. The pieces of plaque may break off and enter the blood (as a blood clot) which can also block the blood flow to any specific organ in the body.
Risk factors
The risk factors for atherosclerosis include:
- Age
- High blood pressure
- Diabetes
- High levels of cholesterol and triglycerides
- Obesity
- Smoking
- A family history of early heart disease
- Lack of exercise
- Unhealthy diet
- High levels of a protein called as C-reactive protein in the blood
- Stress
- Alcohol
Symptoms
Mild atherosclerosis does not have any symptoms. A patient does not usually present symptoms until the artery is narrowed or clogged and cannot supply adequate blood flow to organs and tissues. Sometimes, a blood clot can completely block the blood flow, break apart and can trigger a heart attack or stroke.
Symptoms of atherosclerosis include:
- Heart arteries: Atherosclerosis in heart arteries can lead to symptoms such as pain or discomfort and squeezing or pressure in the chest (Angina), shortness of breath and problems with the rate or rhythm of the heartbeat, tiredness, sleep problems and lack of energy.
- Brain arteries: Atherosclerosis in arteries leading to brain can lead to symptom such as sudden numbness or weakness in arms or legs, inability to move, difficulty speaking, slurring of speech, temporary loss of vision, problems breathing, drooping muscles in the face, confusion, dizziness, trouble walking, loss of balance or coordination, sudden and severe headaches. These symptoms signal a transient ischemic attack (TIA), which if not treated may progress to a stroke.
- Peripheral arteries: Atherosclerosis in the arteries in the arms, legs, and pelvis can lead to symptoms of peripheral artery disease such as numbness, leg pain, and cramps when walking or exercising and sometimes dangerous infections.
- Kidney arteries: Atherosclerosis in arteries leading to kidneys can lead to tiredness, changes in urination, loss of appetite, nausea, swelling in hands or feet, itchiness or numbness, trouble concentrating, high blood pressure or kidney failure.
Diagnosis
Your doctor will examine your medical history; conduct a physical examination and blood tests.
Tests for diagnosis of atherosclerosis include:
- Physical examination: During the physical examination, the doctor might listen to your arteries for abnormal whooshing sound, also called as Bruit, by placing a stethoscope over the affected artery. Your doctor may check to see any weak or absent pulses in the leg or foot as it can be a sign of a blocked artery.
- Ankle/brachial index: This test compares the blood pressure in your ankle with the blood pressure in your arms to see the blood flow. This helps to diagnose peripheral artery disease.
- Blood tests: These tests are done to measure the cholesterol, sugar, proteins, and triglyceride (lipid) levels in the blood. Abnormal levels of these may be a sign of risk of atherosclerosis.
- EKG: Also known as an electrocardiogram, EKG is a painless test that helps to detect and record the electrical activity of the heart. This test helps to note the breathing rate and rhythm of the heart. An EKG also shows signs of heart damage and heart attack.
- Chest X-ray: A chest x-ray helps to take pictures of organs inside your chest, heart, lungs and blood vessels. A chest x-ray can also show signs of heart failure.
- Echocardiography: It is also known as Echo, and uses sound waves to create a moving picture of your heart. This test shows the size and shape of your heart and also provides information on how well the heart chambers and valves are working. This test can also help to identify areas of poor blood flow to the heart, and any previous injury to the heart muscles caused due to poor blood flow.
- Computed Tomography Scan: Also known as a CT scan, this scan creates computer-generated images of the heart, brain and other parts of the body. This test helps to show the hardening and narrowing of arteries. Cardiac CT scan also helps to show whether there is deposition of calcium on the wall of the heart arteries.
- Stress testing: This test is done by making you exercise so that the heart works harder and beats fast while conducting the heart tests. When your heart is working harder, it needs more oxygen and blood supply. Arteries with deposited plaque cannot supply enough oxygen-rich blood to meet the heart’s needs. A stress test can show possible signs and symptoms such as abnormal changes in heart rate, blood pressure, shortness of breath and abnormal changes in your heart rhythm.
- Angiography: This test uses a dye and special x-rays to show the inside pictures of the arteries. This test can show the plaque blocking the arteries and how severe the blockage is.
Complications
The complications of atherosclerosis include:
- Coronary artery disease: This occurs due to blockage and narrowing of the arteries close to the heart, leading to chest pain, heart attack or heart failure.
- Carotid artery disease: This disease occurs when the arteries close to the brain are blocked and can lead to transient ischemic attack, also called a mini-stroke or stroke.
- Peripheral artery disease: This complication occurs when the arteries in your arms or legs are narrowed and blocked leading to circulation problems.
- Aneurysms: It is a serious complication of atherosclerosis, which can occur in any part of the body. An aneurysm is defined as a bulge in the weakened wall of the artery. Bursting of an aneurysm can lead to life-threatening internal bleeding.
- Chronic kidney disease: It is a complication where the arteries supplying blood and nutrients to the heart become narrow and blocked. This can affect kidney function.
Treatment and Prevention
The management of this disease can be done through lifestyle changes, surgery, medications and other procedures.
Lifestyle modifications
A patient with atherosclerosis can reduce the risk of heart disease and stroke by controlling the blood pressure, diabetes, and cholesterol. It is important to lead a healthy lifestyle by quitting smoking, increasing physical activity, eating a balanced and healthy diet, reducing weight, drinking less alcohol and managing stress.
Medications
Your doctor may prescribe certain medications to:
- Reduce fats and cholesterol in the blood (statins)
- Control blood pressure [Angiotensin Converting Enzyme (ACE) inhibitors, beta-blockers, calcium channel blockers and diuretics
- Reduce the risk of developing a blood clot (anticoagulants and antiplatelet agents)
Surgery
Surgery may be recommended to manage severe atherosclerosis. The procedures for treatment of atherosclerosis include:
- Percutaneous Coronary Intervention (PCI): This is also called an angioplasty with a stent. A balloon (stent) is inserted into the narrowed and blocked vessel to inflate and widen it. It may help in improving the blood flow to the heart and relieve chest pain.
- Carotid endarterectomy: This is a surgery done to remove plaque from the carotid artery (brain arteries). This helps to restore the blood flow to the brain which can help in the prevention of stroke.
- Coronary artery bypass surgery (CABG): In this kind of surgery, the blood is redirected around the narrowed or blocked artery by using arteries or veins from other parts of the body. It helps to improve blood flow, relieves chest pain and prevents a heart attack.
Treating and managing atherosclerosis has improved in recent years and has helped reduce the number of deaths from atherosclerosis-related diseases. Adopting a healthy lifestyle can prevent or delay this disease and the ongoing medical care as well surgery can help you avoid complications of atherosclerosis and live a long and healthy life.
References:
- Atherosclerosis | National Heart, Lung, and Blood Institute (NHLBI) [Internet]. Nhlbi.nih.gov. 2018 [cited 3 September 2018]. Available from: https://www.nhlbi.nih.gov/health-topics/atherosclerosis
- Arteriosclerosis / atherosclerosis – Symptoms and causes [Internet]. Mayo Clinic. 2018 [cited 3 September 2018]. Available from: https://www.mayoclinic.org/diseases-conditions/arteriosclerosis-atherosclerosis/symptoms-causes/syc-20350569
- Atherosclerosis [Internet]. Heart and Stroke Foundation of Canada. 2018 [cited 3 September 2018]. Available from: http://www.heartandstroke.ca/heart/conditions/atherosclerosis?qt1m4dc=1
