Atherosclerosis is a disease in which plaque builds up inside your arteries. Arteries are blood vessels that carry oxygen-rich blood to your heart and other parts of your body.
Plaque is made up of fat, cholesterol, calcium, and other substances found in the blood. Over time, plaque hardens and narrows your arteries. This limits the flow of oxygen-rich blood to your organs and other parts of your body.
Atherosclerosis can lead to serious problems, including heart attack, stroke, or even death.
Atherosclerosis can affect any artery in the body, including arteries in the heart, brain, arms, legs, pelvis, and kidneys. As a result, different diseases may develop based on which arteries are affected.
Ischemic heart disease
Ischemic heart disease happens when the arteries of the heart cannot deliver enough oxygen-rich blood to the tissues of the heart when it is needed during periods of stress or physical effort.
Coronary heart disease, also called coronary artery disease, is a type of ischemic heart disease caused by the buildup of plaque in the coronary arteries that supply oxygen-rich blood to your heart.
This buildup can partially or totally block blood flow in the large arteries of the heart. If blood flow to your heart muscle is reduced or blocked, you may have angina (chest pain or discomfort) or a heart attack.
Coronary microvascular disease is another type of ischemic heart disease. It occurs when the heart’s tiny arteries do not function normally.
Carotid Artery Disease
Carotid (ka-ROT-id) artery disease occurs if plaque builds up in the arteries on each side of your neck (the carotid arteries). These arteries supply oxygen-rich blood to your brain. If blood flow to your brain is reduced or blocked, you may have a stroke.
Peripheral Artery Disease
Peripheral artery disease (P.A.D.) occurs if plaque builds up in the major arteries that supply oxygen-rich blood to your legs, arms, and pelvis. If blood flow to these parts of your body is reduced or blocked, you may have numbness, pain, and, sometimes, dangerous infections.
Chronic Kidney Disease
Chronic kidney disease can occur if plaque builds up in the renal arteries. These arteries supply oxygen-rich blood to your kidneys. Over time, chronic kidney disease causes a slow loss of kidney function. The main function of the kidneys is to remove waste and extra water from the body.
Causes of Atherosclerosis
The exact cause of atherosclerosis isn’t known. However, studies show that atherosclerosis is a slow, complex disease that may start in childhood. It develops faster as you age.
Atherosclerosis may start when certain factors damage the inner layers of the arteries. These factors include:
- High amounts of certain fats and cholesterol in the blood
- High blood pressure
- High amounts of sugar in the blood due to insulin resistance or diabetes
Plaque may begin to build up where the arteries are damaged. Over time, plaque hardens and narrows the arteries. Eventually, an area of plaque can rupture (break open).
When this happens, blood cell fragments called platelets (PLATE-lets) stick to the site of the injury. They may clump together to form blood clots. Clots narrow the arteries even more, limiting the flow of oxygen-rich blood to your body.
Depending on which arteries are affected, blood clots can worsen angina (chest pain) or cause a heart attack or stroke.
Risk Factors associated with Atherosclerosis
The exact cause of atherosclerosis isn’t known. However, certain traits, conditions, or habits may raise your risk for the disease. These conditions are known as risk factors. The more risk factors you have, the more likely it is that you’ll develop atherosclerosis.
You can control most risk factors and help prevent or delay atherosclerosis. Other risk factors can’t be controlled.
Major Risk Factors
- 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 time. If you have diabetes or chronic kidney disease, high blood pressure is defined as 130/80 mmHg or higher. (The mmHg is millimeters of mercury—the units used to measure blood pressure.)
- Smoking. Smoking 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. This condition occurs if the body can’t use its insulin properly. Insulin is a hormone that helps move blood sugar into cells where it’s used as an energy source. Insulin resistance may lead to diabetes.
- Diabetes. With this disease, the body’s blood sugar level is too high because the body doesn’t make enough insulin or doesn’t use its insulin properly.
- Overweight or obesity. The terms “overweight” and “obesity” refer to body weight that’s greater than what is considered healthy for a certain height.
- Lack of physical activity. A lack of physical activity can worsen other risk factors for atherosclerosis, such as unhealthy blood cholesterol levels, high blood pressure, diabetes, and overweight and obesity.
- Unhealthy diet. An unhealthy diet can raise your risk for atherosclerosis. Foods that are high in saturated and trans fats, cholesterol, sodium (salt), and sugar can worsen other atherosclerosis risk factors.
- Older age. As you get older, your risk for atherosclerosis increases. Genetic or lifestyle factors cause plaque to build up in your arteries as you age. By the time you’re middle-aged or older, enough plaque has built up to cause signs or symptoms. In men, the risk increases after age 45. In women, the risk increases after age 55.
- Family history of early heart disease. Your risk for atherosclerosis increases if your father or a brother was diagnosed with heart disease before 55 years of age, or if your mother or a sister was diagnosed with heart disease before 65 years of age.
Although age and a family history of early heart disease are risk factors, it doesn’t mean that you’ll develop atherosclerosis if you have one or both. Controlling other risk factors often can lessen genetic influences and prevent atherosclerosis, even in older adults.
Studies show that an increasing number of children and youth are at risk for atherosclerosis. This is due to a number of causes, including rising childhood obesity rates.
Emerging Risk Factors
Scientists continue to study other possible risk factors for atherosclerosis.
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 a sign of inflammation in the body.
Inflammation is the body’s response to injury or infection. Damage to the arteries’ inner walls seems to trigger inflammation and help plaque grow.
People who have low CRP levels may develop atherosclerosis at a slower rate than people who have high CRP levels. Research is under way to find out whether reducing inflammation and lowering CRP levels also can reduce the risk for atherosclerosis.
High levels of triglycerides (tri-GLIH-seh-rides) in the blood also may raise the risk for atherosclerosis, especially in women. Triglycerides are a type of fat.
Studies are under way to find out whether genetics may play a role in atherosclerosis risk.
Other Factors That Affect Atherosclerosis
Other factors also may raise your risk for atherosclerosis, such as:
- Sleep apnea. Sleep apnea is a disorder that causes one or more pauses in breathing or shallow breaths while you sleep. Untreated sleep apnea can raise your risk for 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, especially 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. Women should have no more than one drink containing alcohol a day.
Signs, Symptoms, and Complications
Atherosclerosis usually doesn’t cause signs and symptoms until it severely narrows or totally blocks an artery. Many people don’t know they have the disease until they have a medical emergency, such as a heart attack or stroke.
Some people may have signs and symptoms of the disease. Signs and symptoms will depend on which arteries are affected.
The coronary arteries supply oxygen-rich blood to your heart. If plaque narrows or blocks these arteries (causing a disease called ischemic heart disease), a common symptom is angina. Angina is chest pain or discomfort that occurs when your heart muscle doesn’t get enough oxygen-rich blood.
Angina may feel like pressure or squeezing in your chest. You also may feel it in your shoulders, arms, neck, jaw, or back. Angina pain may even feel like indigestion. The pain tends to get worse with activity and go away with rest. Emotional stress also can trigger the pain.
Other symptoms of ischemic heart disease are shortness of breath and arrhythmias (ah-RITH-me-ahs). Arrhythmias are problems with the rate or rhythm of the heartbeat.
Plaque also can form in the heart’s smallest arteries. This disease is called coronary microvascular disease (MVD). Symptoms of coronary MVD include angina, shortness of breath, sleep problems, fatigue (tiredness), and lack of energy.
The carotid arteries supply oxygen-rich blood to your brain. If plaque narrows or blocks these arteries (a disease called carotid artery disease), you may have symptoms of a stroke. These symptoms may include:
- Sudden weakness
- Paralysis (an inability to move) or numbness of the face, arms, or legs, especially on one side of the body
- Trouble speaking or understanding speech
- Trouble seeing in one or both eyes
- Problems breathing
- Dizziness, trouble walking, loss of balance or coordination, and unexplained falls
- Loss of consciousness
- Sudden and severe headache
Plaque also can build up in the major arteries that supply oxygen-rich blood to the legs, arms, and pelvis (a disease called peripheral artery disease).
If these major arteries are narrowed or blocked, you may have numbness, pain, and, sometimes, dangerous infections.
The renal arteries supply oxygen-rich blood to your kidneys. If plaque builds up in these arteries, you may develop chronic kidney disease. Over time, chronic kidney disease causes a slow loss of kidney function.
Early kidney disease often has no signs or symptoms. As the disease gets worse it can cause tiredness, changes in how you urinate (more often or less often), loss of appetite, nausea (feeling sick to the stomach), swelling in the hands or feet, itchiness or numbness, and trouble concentrating.
Your doctor will diagnose atherosclerosis based on your medical and family histories, a physical exam, and test results.
If you have atherosclerosis, a primary care doctor, such as an internist or family practitioner, may handle your care. Your doctor may recommend other health care specialists if you need expert care, such as:
- A cardiologist. This is a doctor who specializes in diagnosing and treating heart diseases and conditions. You may go to a cardiologist if you have peripheral artery disease (P.A.D.) or coronary microvascular disease (MVD).
- A vascular specialist. This is a doctor who specializes in diagnosing and treating blood vessel problems. You may go to a vascular specialist if you have P.A.D.
- A neurologist. This is a doctor who specializes in diagnosing and treating nervous system disorders. You may see a neurologist if you’ve had a stroke due to carotid artery disease.
- A nephrologist. This is a doctor who specializes in diagnosing and treating kidney diseases and conditions. You may go to a nephrologist if you have chronic kidney disease.
During the physical exam, your doctor may listen to your arteries for an abnormal whooshing sound called a bruit (broo-E). Your doctor can hear a bruit when placing a stethoscope over an affected artery. A bruit may indicate poor blood flow due to plaque buildup.
Your doctor also may check to see whether any of your pulses (for example, in the leg or foot) are weak or absent. A weak or absent pulse can be a sign of a blocked artery.
Types of Diagnostic Tests
Your doctor may recommend one or more tests to diagnose atherosclerosis. These tests also can help your doctor learn the extent of your disease and plan the best treatment.
Blood tests check the levels of certain fats, cholesterol, sugar, and proteins in your blood. Abnormal levels may be a sign that you’re at risk for atherosclerosis.
An EKG is a simple, painless test that detects and records the heart’s electrical activity. The test shows how fast the heart is beating and its rhythm (steady or irregular). An EKG also records the strength and timing of electrical signals as they pass through the heart.
An EKG can show signs of heart damage caused by CHD. The test also can show signs of a previous or current heart attack.
Chest X Ray
A chest x ray takes pictures of the organs and structures inside your chest, such as your heart, lungs, and blood vessels. A chest x ray can reveal signs of heart failure.
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 P.A.D.
Echocardiography (echo) uses sound waves to create a moving picture of your heart. The test provides information about the size and shape of your heart and how well your heart chambers and valves are working.
Echo 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 (CT) scan creates computer-generated pictures of the heart, brain, or other areas of the body. The test can show hardening and narrowing of large arteries.
A cardiac CT scan also can show whether calcium has built up in the walls of the coronary (heart) arteries. This may be an early sign of CHD.
During stress testing, you exercise to make your heart work hard and beat fast while heart tests are done. If you can’t exercise, you may be given medicine to make your heart work hard and beat fast.
When your heart is working hard, it needs more blood and oxygen. Plaque-narrowed arteries can’t supply enough oxygen-rich blood to meet your heart’s needs.
A stress test can show possible signs and symptoms of CHD, such as:
- Abnormal changes in your heart rate or blood pressure
- Shortness of breath or chest pain
- Abnormal changes in your heart rhythm or your heart’s electrical activity
As part of some stress tests, pictures are taken of your heart while you exercise and while you rest. These imaging stress tests can show how well blood is flowing in various parts of your heart. They also can show how well your heart pumps blood when it beats.
Angiography (an-jee-OG-ra-fee) is a test that uses dye and special x rays to show the inside of your arteries. This test can show whether plaque is blocking your arteries and how severe the blockage is.
A thin, flexible tube called a catheter is put into a blood vessel in your arm, groin (upper thigh), or neck. Dye that can be seen on an x-ray picture is injected through the catheter into the arteries. By looking at the x-ray picture, your doctor can see the flow of blood through your arteries.
Other tests are being studied to see whether they can give a better view of plaque buildup in the arteries. Examples of these tests include magnetic resonance imaging (MRI) and positron emission tomography (PET).
Treatment for Atherosclerosis
Treatments for atherosclerosis may include heart-healthy lifestyle changes, medicines, and medical procedures or surgery. The goals of treatment include:
- Lowering the risk of blood clots forming
- Preventing atherosclerosis-related diseases
- Reducing risk factors in an effort to slow or stop the buildup of plaque
- Relieving symptoms
- Widening or bypassing plaque-clogged arteries
Sometimes lifestyle changes alone aren’t enough to control your cholesterol levels. For example, you also may need statin medications to control or lower your cholesterol. By lowering your blood cholesterol level, you can decrease your chance of having a heart attack or stroke. Doctors usually prescribe statins for people who have:
- Coronary heart disease, peripheral artery disease, or had a prior stroke
- High LDL cholesterol levels
Doctors may discuss beginning statin treatment with people who have an elevated risk for developing heart disease or having a stroke.
Your doctor also may prescribe other medications to:
- Lower your blood pressure
- Lower your blood sugar levels
- Prevent blood clots, which can lead to heart attack and stroke
- Prevent inflammation
Take all medicines regularly, as your doctor prescribes. Don’t change the amount of your medicine or skip a dose unless your doctor tells you to. You should still follow a heart healthy lifestyle, even if you take medicines to treat your atherosclerosis.
Medical Procedures and Surgery
If you have severe atherosclerosis, your doctor may recommend a medical procedure or surgery.
Percutaneous coronary intervention (PCI), also known as coronary angioplasty, is a procedure that’s used to open blocked or narrowed coronary (heart) arteries. PCI can improve blood flow to the heart and relieve chest pain. 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. In CABG, arteries or veins from other areas in your body are used to bypass or go around your 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. For this surgery, a healthy blood vessel is used to bypass a narrowed or blocked artery in one of the legs. The healthy blood vessel redirects blood around the blocked artery, improving blood flow to the leg.
Carotid endarterectomy is a type of surgery to remove plaque buildup from the carotid arteries in the neck. This procedure restores blood flow to the brain, which can help prevent a stroke.