What is atherosclerosis?
The clogging of the arteries due to progressive fat deposition and plaque (fatty and fibrous tissue) formation is known as atherosclerosis. Arteries carry oxygen and nutrients from the heart to the rest of the body. Plaque build-up leads to narrowing and hardening of the arteries, restricting the blood and nutrient supply to the organs. Plaque deposition can increase the risk of blood clot formation that can block the blood flow to the heart, brain or other organs of the body.
The precise cause of atherosclerosis is not known. Atherosclerosis can start with an injury or damage of the inner layer (endothelium) of the arteries due to:
- High blood pressure
- Elevated levels of cholesterol and triglycerides
- Insulin resistance, diabetes or obesity
The inner layer of the blood vessels is damaged by smoking and high blood pressure. Cholesterol, fat, platelets, calcium and cellular debris then accumulate in the arterial walls at the site of the damage. This accumulation can also stimulate the cells of the arterial wall to produce other substances which in turn, can result in the formation of atherosclerotic lesions. Around these cells, fats can accumulate, narrowing and thickening the arterial walls, which reduces the blood flow and oxygen supply to vital organs.
Atherosclerosis can occur in any artery in our body, including the heart, brain, legs and kidneys. Blood clots form at the site of these atherosclerotic changes, which can block the blood flow to different organs. When the oxygen supply to the heart is reduced, it can lead to a heart attack and when the oxygen supply to the brain is restricted, stroke can occur. Gangrene occurs when the oxygen supply to the extremities is cut off.
The deposition of the plaque occurs gradually over time; the risk factors for atherosclerosis include:
- High blood pressure and cholesterol levels
- Obesity or overweight
- High-fat diet
- Excessive alcohol intake
- Family history of atherosclerosis and cardiovascular disease
- South Asian, African or African-Caribbean descent
Until there is a marked narrowing or clogging of the arteries, symptoms aren’t evident.
The commonly reported symptoms depend on the organ (heart, brain, extremities, kidneys, etc.) whose blood vessels are narrowed due to atherosclerosis and the overlying thrombosis. These symptoms may include:
- Heart: Chest pain, fatigue, shortness of breath
- Brain: Confusion, giddiness, transient ischemic attacks, stroke, loss of consciousness
- Extremities: Pain in the legs or arm or wherever a blocked artery is present, muscle weakness
- Kidneys: chronic renal failure
Your doctor will conduct a physical examination and check for:
- Any weakening of pulse
- Any abnormal bulging of an artery (an aneurysm)
- Lowered blood pressure in an affected limb
- Listen to your heart for any atypical sounds
The diagnostic tests can include:
- Blood tests: To check cholesterol levels
- Doppler ultrasound: It uses sound waves to form a picture of the artery which can show atherosclerotic depositions or a blockage.
- Ankle-brachial index test: This looks for a blockage in your limbs by comparing the blood pressure in each of the limbs.
- Computed tomography angiography (CTA) or Magnetic resonance arteriography (MRA): Here pictures of the major arteries of the body are created using advanced techniques. These diagnostic techniques can detect any hardening or narrowing of the arteries.
- Cardiac angiogram: A radioactive dye is injected into the arteries which show up on X-rays, revealing any blockages in the arteries.
- An electrocardiogram (EKG): It measures the electrical activity of the heart to check for regions with decreased blood supply.
- Stress test: The blood pressure and EKG are monitored while one exercises.
Treatment involves changes in your lifestyle which aim at limiting your fat and cholesterol intake.
Medications are prescribed to prevent the worsening of atherosclerosis. Some of them include:
- Cholesterol-lowering medication: These include statins and derivatives of fibric acid.
- Thrombolytic therapy: It involves injecting a drug into the affected artery to dissolve a blood clot.
- Anticoagulants and Antiplatelet Drugs: These drugs are prescribed to prevent the blood from clotting and clogging the arteries.
- Calcium channel or beta blockers: These drugs are prescribed for lowering the blood pressure.
- Angiotensin-converting enzyme (ACE) inhibitors: They help in preventing the narrowing of the arteries.
- Diuretics: To aid in lowering of your blood pressure.
When the symptoms are severe in nature, surgical procedures may be required which can include:
- Angioplasty and stent placement: Angioplasty involves the use of a thin, flexible tube (catheter) and a balloon to expand the artery. A stent (mesh tube) is usually placed in the artery to keep the artery open.
- Bypass surgery: A blood vessel from another part of the body or a synthetic tube is used for diverting the blood around the narrowed or blocked artery.
- Endarterectomy: The fatty deposits are removed surgically from the artery.
Following changes in your lifestyle can help in prevention as well as progression of atherosclerosis:
- Adopting a low-fat diet which is low in saturated fats and cholesterol
- Avoiding fatty foods
- Including fish in your diet
- Exercising regularly
- Stop smoking, if you are a smoker
- Losing weight if you are overweight or obese
- Moderating/reducing your alcohol consumption
Complications of atherosclerosis can include:
- Coronary Artery Disease: It occurs when the coronary arteries of the heart harden. These arteries are responsible for providing blood and oxygen to the heart muscles. Plaque deposition will prevent blood flow to the heart.
- Carotid Artery Disease: The carotid arteries are present in the neck and supply blood to the brain. Plaque build-up in their walls can reduce the circulation of blood and oxygen to the brain which can lead to a transient ischemic attack (TIA) or stroke.
- Peripheral Artery Disease: The legs, arms, and lower body get blood and oxygen supply through the arteries. Hardening of the arteries can lead to reduced circulation in such regions.
- Kidney Disease: When the renal arteries supplying oxygenated blood to the kidneys are narrowed, it can lead to kidney failure.
- Aneurysms: Any bulges in your artery are referred as aneurysms. These can burst and lead to medical emergencies. Abdominal aneurysms are common due to atherosclerosis.
Seek immediate medical attention, if you notice any early symptoms and signs of inadequate blood flow to vital organs like heart, brain or kidneys. Early diagnosis and treatment can avert potential emergencies like a heart attack or a stroke.
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- What is atherosclerosis? National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/health-topics/topics/atherosclerosis. Accessed 29 Jun. 16.
- American Heart Association. http://www.heart.org/HEARTORG/Conditions/Cholesterol/WhyCholesterolMatters/Atherosclerosis_UCM_305564_Article.jsp#.V3NrSJN97R1. Accessed 29 Jun. 16.
- NHSChoices. http://www.nhs.uk/conditions/atherosclerosis/Pages/Introduction.aspx. Accessed 29 Jun. 16.
- Lusis AJ. Atherosclerosis. Nature. 2000;407(6801):233-241.