Causes, Symptoms and Treatment of Atherosclerosis
Atherosclerosis is the build-up of a deposit known as plaque on the inner wall of the arteries. Plaque is made up of calcium, cholesterol and fat. As more of it is deposited, the amount of space left for blood to flow becomes narrowed and restricted. Plaque build-up takes place slowly over time, which is why older people are more likely to show symptoms.
Sometimes plaque can burst (rupture), which causes platelets to accumulate in the area and hence results in clotting. If this happens in the arteries of the heart it can result in angina or even heart attack (myocardial infarction). If it occurs in one of the carotid arteries, it can result in a stroke. Plaque rupture is thought to be typically caused by inflammation.
Plaque can form anywhere in the arterial system including the coronary artery, the carotid arteries, the renal arteries and the peripheral arteries, which are the arteries that transport oxygenated blood to your limbs and pelvic system. As a result of this, atherosclerosis can lead to other diseases including coronary heart disease, carotid artery disease, chronic kidney disease and peripheral arterial disease. There is another condition known as coronary microvascular disease, which is caused by plaque build-up in the smallest arteries of the heart.
Atherosclerosis should not be confused with arteriosclerosis, which is the term used to describe hardening of the arteries as opposed to plaque build-up.
Fast Facts about Atherosclerosis
- Atherosclerosis is the build-up of plaque on the inner wall of your arteries. Plaque is made up of calcium, cholesterol and fat
- It can lead to angina and to serious problems such as heart attack and stroke
- Risk factors include bad diet, obesity, smoking, excessive alcohol intake, lack of exercise, high blood pressure, diabetes/insulin resistance, stress, age and a family history of the disease
- Atherosclerosis can be detected by testing to see whether you have bruit (an abnormal sound made by the heart) or a weak pulse, but diagnosis can only be confirmed via tests such as chest X-ray, EKG, echocardiography, angiography and a CT scan
- Treatments include diet/lifestyle changes, medication with statins, fibrates or clotting inhibitors, and in more serious cases, surgery
Common Causes of Atherosclerosis
The build-up of atherosclerotic plaque is associated with a diet that is high in cholesterol and certain types of fat. Plaque is most likely to form where an artery wall has been damaged, because the damage and resultant scarring provides a site for the plaque to anchor itself more easily. Hypertension (high blood pressure) is one thing that can cause damage to artery walls. Another is the chemicals in cigarette smoke, which is why smoking is a huge risk factor in heart disease. Not only does smoking make it more likely that you will get damaged arteries, but it also increases your blood pressure. A third risk factor is diabetes. If you have diabetes, it means that your pancreas produces insufficient insulin, the hormone that encourages your cells to utilise the glucose in your blood. A lack of insulin therefore means that glucose builds up in the bloodstream because it can’t be used by your cells, and causes damage to your blood vessel walls.
Risk Factors for Atherosclerosis
As already mentioned, you have a greater risk of developing atherosclerosis if:
- You have a poor diet, one that contains too much fat (particularly trans and saturated fats) and so-called ‘bad’ LDL cholesterol, and not enough ‘good’ HDL cholesterol. Too much salt and sugar is also bad.
- You have high blood pressure.
- You are a smoker.
- You are overweight or obese.
- You have diabetes or insulin resistance. In diabetes, the body doesn’t produce enough insulin, while insulin resistance means that the body’s cells are less effective at utilizing insulin. Both diabetes and insulin resistance result in a build-up of glucose in the bloodstream, and hence increase the risk of arterial damage and atherosclerosis.
- You drink large amounts of alcohol. Alcohol increases the blood pressure, and raises levels of certain types of fat known as triglycerides in the blood.
- You are under stress and often find yourself in situations where you become angry.
You are more likely to get atherosclerosis if you are overweight or obese, and you don’t take any exercise.
Age is another risk factor – generally speaking, you are more at risk the older you are because plaque build-up occurs over time. If atherosclerosis runs in your family, then you yourself are also at greater risk.
There are a few other, perhaps less well-known risk factors for atherosclerosis. Studies show that people who suffer from obstructive sleep apnea are more at risk of developing (or are more likely to have) atherosclerosis. The exact nature of the link is as yet uncertain – we are not sure which condition causes the other, or if there is a third as yet unidentified cause that underlies the two.
Scientists have found that higher than normal levels of C-reactive protein in the blood are also an indication that atherosclerosis may be present. Studies on mice show that C-reactive protein may actually increase formation of atherosclerotic plaques.
Symptoms of Atherosclerosis
Atherosclerosis can build up for years before it actually causes symptoms. When symptoms do finally develop, they will vary depending on which arteries have experienced the plaque build-up. If the coronary arteries (the arteries in the heart) are affected, you may experience chest pain known as angina, which results from insufficient oxygen supply to the heart muscle. You may also have arrhythmia (irregular or abnormally fast/slow heartbeat), as well as shortness of breath. You might also have trouble sleeping and generally feel tired and lacking in energy.
If the carotid arteries are affected, the first sign that anything is wrong might be a stroke. Symptoms of stroke are tingling, paralysis, numbness or weakness in your face or limbs, often just on one side. You may get dizzy or have trouble talking or understanding what is said to you. You might have problems with vision, and you may also get a headache which feels different from a “normal” headache. Stroke can result in long-term brain damage and physical disability. Instead of having a full-blown stroke, you might get “warning” symptoms, including:
- A bruit. This is a noise made by the heart which suggests that blood flow has been restricted in some way, and may be discovered by your doctor during a routine examination with a stethoscope.
- A transient ischemic attack. Also known as a mini-stroke, this has the same symptoms as a stroke but these symptoms disappear in a day or less.
If the peripheral arteries are affected, you might experience feeling of numbness and pain when walking, poor healing of wounds and even infection. Atherosclerosis in the renal arteries can cause chronic kidney disease with symptoms such as nausea and urinary problems.
Certain physical symptoms, such as a bruit (detected by listening to your heart with a stethoscope), or a weak pulse anywhere in your body, can indicate that there is poor circulation and hence a possible blockage. Blood tests will also detect some of the common “markers” for atherosclerosis – e.g. high levels of cholesterol, sugar, fats and C-reactive protein.
However, other tests must be carried out to confirm that you have atherosclerosis. These tests include electrocardiography (EKG), which shows any abnormalities in your heart rate and rhythm; a chest X-ray; echocardiography (an ultrasound-based technique that detects areas where blood isn’t flowing properly); a CT scan; and an angiography, which is another X-ray based test that uses a contrast agent to make your arteries show up better in the X-ray picture.
Since any problems are more likely to show up while your heart is under stress, you may be given a stress test during EKG or echocardiography, which involves exercising or taking drugs in order to make your heart beat faster and work harder.
Another test is the ankle/brachial index, which is used to diagnose peripheral arterial disease. This involves measuring the blood pressure in your ankle and arm, and comparing the two.
Treatment Options for Atherosclerosis
There are three main approaches to treatment: lifestyle alterations, drugs and surgical procedures.
Lifestyle changes involve losing weight, taking more exercise, giving up smoking, improving your diet and managing your stress levels more effectively. Ensure that you eat a diet rich in vegetables, fresh fruit, legumes, whole grains/fiber and foods that contain high levels of omega-3 fatty acids, like oily fish (e.g. tuna, salmon and mackerel). You should also cut down your intake of salt, sugar and alcohol.
Your doctor may suggest an eating plan called DASH (Dietary Approaches to Stop Hypertension), or the TLC (Therapeutic Lifestyle Changes) program, which encompasses diet, exercise and weight control.
The second treatment strategy is drugs/medication. These include statins, which reduce levels of ‘bad’ LDL cholesterol and triglycerides, and also help to increase levels of ‘good’ HDL cholesterol. Drugs known as fibrates (e.g. gemfibrozil and fenofibrate) can also be used to lower triglyceride levels. Other drugs that reduce cholesterol levels include bile acid sequestrants and plant sterols. If you are diagnosed with atherosclerosis you may also be prescribed drugs to reduce blood pressure and the risk of clotting; examples of anticlotting agents include aspirin and clopidogrel.
When it comes to surgical procedures, there are several options. One is angioplasty and stenting of the affected artery. This technique involves inserting a catheter into a blood vessel and threading it along until it reaches the site of the plaque. The catheter has a balloon on the end, which is inflated in order to compress the plaque and thus reduce the blockage/narrowing. A mesh tube known as a stent can then be placed in the artery to prevent further blockage.
If you have plaque in the carotid arteries, there is a technique known as carotid endarterectomy where an incision is made in your neck while you’re under anesthetic, to expose the carotid artery. The artery is then cut open and the plaque is taken out.
If you have atherosclerosis in your coronary arteries, you may be recommended to have coronary artery bypass grafting, where healthy blood vessels from elsewhere in the body are used to bypass the atherosclerotic section of coronary artery so that the blood flows through the graft instead. Bypass grafting may also be used for blocked arteries in the legs.
Prevention of Atherosclerosis
You should work out which risk factors you have and if possible reduce them, either by changing your lifestyle (quitting smoking, eating a better diet, losing weight, reducing your alcohol consumption and cutting down your stress levels), or by taking medication as directed by your doctor.
If you have a family history of atherosclerosis there is nothing you can do about this, although you should tell your doctor about it so that he or she knows you are at greater risk.
Coping with Atherosclerosis
You should try to lose weight, take more exercise, stop smoking, reduce alcohol intake and improve your diet. Enlist the help of your family and friends to improve your lifestyle, and follow any eating or lifestyle programs that your doctor recommends.
If you are prescribed medication to treat or prevent atherosclerosis, you should take these as directed and report any problems to your doctor.
If your symptoms are making you feel depressed or anxious, counselling or joining a support group may be of benefit.
If you develop signs of a stroke or think you might be having a heart attack, call emergency immediately. Tell anyone you live with about the signs of stroke so that they can get help for you if needed.
Where to Get More Information: Atherosclerosis Journal