Atherosclerosis

Atherosclerosis

Atherosclerosis, (ath-er-o-skler-O-sis) comes from the Greek words athero - meaning gruel or paste and sclerosis meaning hardness - and is a hardening of the arteries - it is the most common cause of heart disease.

Precisely what causes atherosclerosis remains unknown, but research suggests that atherosclerosis is a slow, complex disease which may start in childhood and as people age, it develops faster.

Atherosclerosis causes plaque to accumulate on the inner walls of arteries, the blood vessels which carry oxygen-rich blood throughout the body, and as the artery walls thicken, the pathway for blood narrows and this can decrease or block blood flow through the body.

The plaque build up is the result of high levels of cholesterol, fat, calcium, and other substances in the blood - high blood cholesterol levels increase the likelihood that plaque will build up on the artery walls - this process begins in the majority of people when they are children or teenagers and worsens as they get older.

As a rule atherosclerosis does not cause symptoms until an artery becomes narrowed or blocked, once this happens symptoms may include angina and cramping leg pain when walking - when the flow of oxygen-rich blood to organs and other parts of the body is reduced. serious problems, including heart attack, stroke, or even death can result.

Diseases Associated with Atherosclerosis

Atherosclerosis can affect any artery in the body, including arteries in the heart, brain, arms, legs, and pelvis and as a result, different diseases may develop based on which arteries are affected, such as coronary artery disease, carotid artery disease and peripheral arterial disease.

Coronary artery disease (CAD) or heart disease occurs when plaque builds up in the coronary arteries which supply oxygen-rich blood to the heart - when blood flow to the heart is reduced or blocked, it can lead to chest pain and heart attack - CAD is the leading cause of death in the United States - the symptoms of CAD are shortness of breath and arrhythmias (irregular heartbeats).

Angina, heart attack (Myocardial Infarction), Stroke (Cerebrovascular Accident), Transient Ischemic Attack (TIA) or mini-stroke and Peripheral Vascular Disease (Peripheral Arterial Disease) are also linked to atherosclerosis.

Angina is chest pain or discomfort that occurs when your heart muscle doesn't get enough oxygen-rich blood and may feel like pressure or a squeezing pain in the chest and also in the shoulders, arms, neck, jaw, or back - the pain tends to worsen with activity and goes away when resting - emotional stress can also can trigger the pain.

Carotid artery disease occurs when plaque builds up in the carotid arteries which supply oxygen-rich blood to the brain - when blood flow to the brain is reduced or blocked, it can lead to stroke - symptoms include sudden numbness, weakness, and dizziness.

Peripheral arterial disease (PAD) occurs when plaque builds up in the major arteries that supply oxygen-rich blood to the legs, arms, and pelvis - when blood flow to these parts of the body is reduced or blocked, it can lead to numbness, pain, and sometimes dangerous infections.

However, some people with atherosclerosis have no signs or symptoms and may not be diagnosed until after a heart attack or stroke.

Risk Factors for Atherosclerosis

Coronary artery disease is the leading cause of death in the United States and while the exact cause of atherosclerosis remains unknown, certain traits, conditions, or habits may raise a person's chance of developing it.

These conditions are known as risk factors and a person's chances of developing atherosclerosis increase with the number of risk factors they have - most risk factors can be controlled and atherosclerosis can be prevented or delayed - these include high Cholesterol and low-density lipoprotein (LDL) in the blood, low level of high-density lipoprotein (HDL) in the blood, Hypertension (high blood pressure), tobacco smoke, Diabetes Mellitus, Obesity, inactive lifestyle, age - a family history of heart disease is also a risk factor and the one which cannot be controlled.

Unhealthy blood cholesterol levels - this includes high LDL cholesterol (sometimes called bad cholesterol) and low HDL cholesterol (sometimes called good cholesterol).

High blood pressure - blood pressure is considered high if it stays at or above 140/90 mmHg over a period of time.

Smoking - this can damage and tighten blood vessels, raise cholesterol levels, and raise blood pressure - smoking also doesn't allow enough oxygen to reach the body's tissues.

Insulin resistance - Insulin is a hormone that helps move blood sugar into cells where it's used and insulin resistance occurs when the body cannot use its own insulin properly.

Diabetes - this is a disease in which the body's blood sugar level is high because the body doesn't make enough insulin or does not use its insulin properly.

Overweight or obesity - overweight is having extra body weight from muscle, bone, fat, and/or water - obesity is having a high amount of extra body fat.

Lack of physical activity - lack of activity can worsen other risk factors for atherosclerosis.

Age - as the body ages the risk for atherosclerosis increases and genetic or lifestyle factors cause plaque to gradually build in the arteries - by middle-age or older, enough plaque has built up to cause signs or symptoms, in men, the risk increases after age 45, while in women, the risk increases after age 55.

Family history of early heart disease - the risk for atherosclerosis increases if a father or a brother was diagnosed with heart disease before 55 years of age, or if a mother or a sister was diagnosed with heart disease before 65 years of age but though age and a family history of early heart disease are risk factors, it does not mean that you will develop atherosclerosis if you have one or both. Making lifestyle changes and/or taking medicines to treat other risk factors can often lessen the genetic influences and prevent atherosclerosis from developing, even in older adults.

Emerging Risk Factors

Scientists continue to study other possible risk factors for atherosclerosis and have found that high levels of a protein called C-reactive protein (CRP) in the blood may raise the risk for atherosclerosis and heart attack - high levels of CRP are proof of inflammation in the body which is the body's response to injury or infection - damage to the arteries' inner walls appears to trigger inflammation and help plaque grow.

People with low CRP levels may get atherosclerosis at a slower rate than people with high CRP levels and research is currently under way to establish whether reducing inflammation and lowering CRP levels also can reduce the risk of atherosclerosis.

High levels of fats called triglycerides in the blood also may raise the risk of atherosclerosis, particularly in women.

Other Factors That Affect Atherosclerosis

Other risk factors also may raise your risk for developing atherosclerosis include:

Sleep apnoea - a disorder in which the breathing stops or gets very shallow while a person is sleeping - untreated sleep apnoea can raise the chances of high blood pressure, diabetes, and even a heart attack or stroke.

Stress - research shows that the most commonly reported "trigger" for a heart attack is an emotionally upsetting event-particularly one involving anger.

Alcohol - heavy drinking can damage the heart muscle and worsen other risk factors for atherosclerosis - men should have no more than two drinks containing alcohol a day, while women should have no more than one drink containing alcohol a day.

Diagnosing Atherosclerosis

Doctors have an arsenal of diagnostic tests and tools they can access to confirm the presence of Atherosclerosis - these include an angiogram (Arteriogram), cholesterol tests, a chest x-ray, a CT (computed tomography) scan, Duplex scanning, an echocardiogram, an electrocardiogram (ECG or EKG), an exercise stress test (cardiac stress test), an intravascular ultrasound, an MRI (magnetic resonance imaging) scan, a PET (positron emission tomography) scan and a pharmacologic stress test.

Blood Tests - blood tests check the levels of certain fats, cholesterol, sugar, and proteins in your blood and abnormal levels may indicate risk factors for atherosclerosis.

EKG (Electrocardiogram) - an EKG is a simple test that detects and records the electrical activity of the heart and shows how fast the heart is beating and whether it has a regular rhythm. It also shows the strength and timing of electrical signals as they pass through each part of the heart. Certain electrical patterns that the EKG detects can suggest whether CAD is likely. An EKG also can show signs of a previous or current heart attack.

Chest X Ray - a chest x ray takes a picture of the organs and structures inside the chest, including the heart, lungs, and blood vessels - a chest x ray can also reveal signs of heart failure.

Ankle/Brachial Index - this test compares the blood pressure in your ankle with the blood pressure in your arm to see how well your blood is flowing. This test can help diagnose PAD.

Echocardiography - this test uses sound waves to create a moving picture of your heart and provides information about the size and shape of your heart and how well your heart chambers and valves are working. The test also can identify areas of poor blood flow to the heart, areas of heart muscle that aren't contracting normally, and previous injury to the heart muscle caused by poor blood flow.

Computed Tomography Scan - a computed tomography, or CT, scan creates computer-generated images of the heart, brain, or other areas of the body. The test can often show hardening and narrowing of large arteries.

Stress Testing - during stress testing, exercise is used to make the heart work hard and beat fast while heart tests are performed - if a person is unable to exercise, medicines are given to speed up the heart rate. When the heart is beating fast and working hard, it needs more blood and oxygen and arteries narrowed by plaque cannot supply enough oxygen-rich blood to meet the heart's needs - a stress test can show possible signs of CAD, such as:

  • Abnormal changes in the heart rate or blood pressure
  • Symptoms such as shortness of breath or chest pain
  • Abnormal changes in your heart rhythm or your heart's electrical activity

During a stress test, if a person is unable to exercise for as long as is considered normal for their age, it may be a sign that not enough blood is flowing to the heart. - but other factors besides CAD can prevent a person from exercising long enough (for example, lung diseases, anaemia, or poor general fitness).

Some stress tests use a radioactive dye, sound waves, positron emission tomography (PET), or cardiac magnetic resonance imaging (MRI) to take pictures of your heart when it's working hard and when it's at rest. - these imaging stress tests can show how well blood is flowing in the different parts of the heart and can also can show how well the heart pumps blood when it beats.

Angiography - angiography is a test that uses dye and special x -rays to show the insides of arteries and can reveal whether plaque is blocking the arteries and how severe the plaque is. A thin, flexible tube called a catheter is put into a blood vessel in the arm, groin (upper thigh), or neck. A dye that can be seen on x -ray is then injected into the arteries and by looking at the x-ray picture, a doctor can see the flow of blood through the arteries.

Surgeries and Procedures for Atherosclerosis

Surgeries and procedures for atherosclerosis include Angioplasty, Stent placement, Coronary Artery Bypass surgery, Carotid artery surgery and Atherectomy. Such procedures may involve the use of medical devices such as stent and drug-eluting stent or a cardiac angioplasty or atherectomy device.

Angioplasty is a procedure to open blocked or narrowed coronary (heart) arteries and can improve the blood flow to the heart, relieve chest pain, and possibly prevent a heart attack. Sometimes a small mesh tube called a stent is placed in the artery to keep it open after the procedure.

Coronary artery bypass grafting (CABG) is a type of surgery - where arteries or veins from other areas in the body are used to bypass the narrowed coronary arteries. CABG can improve blood flow to your heart, relieve chest pain, and possibly prevent a heart attack.

Bypass grafting also can be used for leg arteries - with this surgery, a healthy blood vessel is used to bypass a narrowed or blocked blood vessel in one of the legs, the healthy blood vessel redirects blood around the artery, improving blood flow to the leg.

Carotid artery surgery removes plaque build-up from the carotid arteries in the neck, opens the arteries and improves blood flow to the brain. Carotid artery surgery can help prevent a stroke.

Depending on their condition a doctor may refer a patient with Atherosclerosis to a cardiologist (a doctor who specializes in treating people with heart problems) if they have coronary artery disease (CAD) - or a vascular specialist (a doctor who specializes in treating people with blood vessel problems) if they have peripheral arterial disease (PAD) - or a neurologist (a doctor who specializes in treating people with disorders of the nervous system) if they have had a stroke due to carotid artery disease.

Treatments for Atherosclerosis

The treatment of Atherosclerosis aims to relieve symptoms and reduce the risk factors in an effort to slow, stop, or reverse the build-up of plaque. Treatment will include lowering the risk of blood clots forming, widening or bypassing clogged arteries and preventing diseases related to atherosclerosis, along with lifestyle changes.

If cholesterol levels are high a doctor may recommend Therapeutic Lifestyle Changes (TLC) - a three-part program that includes a healthy diet, physical activity, and weight management.

With the TLC diet, less than 7% of daily calories should come from saturated fat found mainly in meat, poultry and dairy products and no more than 35% of daily calories should come from all fats, including saturated, trans, monounsaturated, and polyunsaturated fats and less than 200 mg of cholesterol daily.

Foods high in soluble fibre are also part of a healthy eating plan as they help block the digestive track from absorbing cholesterol. These foods include: whole grain cereals such as oatmeal and oat bran, fruits such as apples, bananas, oranges, pears, and prunes, legumes such as kidney beans, lentils, chick peas, black-eyed peas, and lima beans.

A diet high in fruits and vegetables can increase important cholesterol-lowering compounds in the diet called plant stanols or sterols, which work like soluble fibre.

Fish is also an important part of a heart healthy diet as fish is a good source of omega-3 fatty acids, which may help protect the heart from blood clots and inflammation and reduce the risk for heart attack - two fish meals should be eaten each week - fish high in omega-3 fats are salmon, tuna (canned or fresh), and mackerel.

It is also good to limit the amount of sodium (salt) that is eaten by choosing low-sodium and low-salt foods and "no added salt" foods and seasonings at the table or when cooking and examining food labels for sodium content.

There are also a range of medications which can be used to treat Atherosclerosis - these include anticoagulants, aspirin, beta blockers, bile acid sequestrants, calcium channel blockers, Ezetimibe, Fibrates, Glycoprotein IIb/IIIa Receptor Inhibitors, Niacin (Nicotinic Acid), Nitrates, Platelet Inhibitors, Statins (HMG-CoA Reductase Inhibitors) and Thrombolytics

Preventing and Managing Atherosclerosis

The main treatment for atherosclerosis is lifestyle changes which along with ongoing medical care, can help a person live a healthier life.

Atherosclerosis is best prevented and managed by a healthy lifestyle and a healthy diet, where high blood pressure and high blood cholesterol are controlled, regular exercise undertaken and a healthy weight is maintained - diabetes mellitus must be prevented or managed and smoking stopped or never started.

Even though improvements in treatments have reduced the number of deaths from atherosclerosis-related diseases and have improved the quality of life for people with these diseases, the number of people diagnosed with atherosclerosis still remains high.

Scientists continue to search for ways to improve the health of people who have atherosclerosis or are likely to get it by finding more effective medicines, identifying those most at risk earlier and exploring alternative treatments.

Those with atherosclerosis are urged to work closely with their doctor and other health carers to avoid serious problems such as heart attack and stroke and take steps to control the disease.