Coronary Microvascular Disease

What Is

Coronary microvascular disease (MVD) is heart disease that affects the tiny coronary (heart) arteries. In coronary MVD, the walls of the heart's tiny arteries are damaged or diseased.

Coronary MVD is different from traditional coronary heart disease (CHD), also called coronary artery disease. In CHD, a waxy substance called plaque (plak) builds up in the large coronary arteries.

Plaque narrows the heart's large arteries and reduces the flow of oxygen-rich blood to your heart muscle. The buildup of plaque also makes it more likely that blood clots will form in your arteries. Blood clots can mostly or completely block blood flow through a coronary artery.

In coronary MVD, however, the heart's tiny arteries are affected. Plaque doesn't create blockages in these vessels as it does in the heart's large arteries.

Coronary Microvascular Disease

Figure A shows the small coronary artery network (microvasculature), containing a normal artery and an artery with coronary MVD. Figure B shows a large coronary artery with plaque buildup.

Overview

Both men and women who have coronary microvascular disease often have diabetes or high blood pressure. Some people who have coronary microvascular disease may have inherited heart muscle diseases.

Diagnosing coronary microvascular disease has been a challenge for doctors. Standard tests used to diagnose coronary heart disease aren’t designed to detect coronary microvascular disease. More research is needed to find the best diagnostic tests and treatments for the disease.

Outlook

Most of what is known about coronary MVD comes from the National Heart, Lung, and Blood Institute's Wise study (Women's Ischemia Syndrome Evaluation).

The WISE study started in 1996. The goal of the study was to learn more about how heart disease develops in women.

Currently, research is ongoing to learn more about the role of hormones in heart disease and to find better ways to diagnose coronary MVD.

Studies also are under way to learn more about the causes of coronary MVD, how to treat the disease, and the expected health outcomes for people with coronary MVD.

Other Names
  • Cardiac syndrome X
  • Nonobstructive coronary heart disease
Causes

The same risk factors that cause atherosclerosis may cause coronary microvascular disease. Atherosclerosis is a disease in which plaque builds up inside the arteries.

Risk factors for atherosclerosis include:

  • Diabetes. It is a disease in which the body’s blood sugar level is too high because the body doesn’t make enough insulin or doesn’t use its insulin properly.
  • Family history of early heart disease. Your risk of atherosclerosis increases if your father or a brother was diagnosed with heart disease before age 55, or if your mother or a sister was diagnosed with heart disease before age 65.
  • 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.)
  • 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 for energy. Overtime, insulin resistance can lead to diabetes.
  • Lack of physical activity. Physical inactivity can worsen some other risk factors for atherosclerosis, such as unhealthy blood cholesterol levels, high blood pressure, diabetes, and overweight or obesity.
  • Older age. As you age, your risk for atherosclerosis increases. The process of atherosclerosis begins in youth and typically progresses over many decades before disease develops. 
  • Overweight and obesity. The terms “overweight” and “obesity” refer to body weight that’s greater than what is considered healthy for a certain height.
  • Smoking. Smoking can damage and tighten blood vessels, lead to unhealthy cholesterol levels, and raise blood pressure. Smoking also doesn’t allow enough oxygen to reach the body’s tissues.
  • Unhealthy blood cholesterol levels. This includes high LDL (“bad”) cholesterol and low HDL (“good”) cholesterol.
  • 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 risk factors for atherosclerosis.

In women, coronary microvascular disease also may be linked to low estrogen levels occurring before or after menopause. Also, the disease may be linked to anemia or conditions that affect blood clotting. Anemia is thought to slow the growth of cells needed to repair damaged blood vessels.

Researchers continue to explore other possible causes of coronary microvascular disease.

Risk Factors

Coronary microvascular disease can affect both men and women. However, women may be at risk for coronary microvascular disease if they have lower than normal levels of estrogen at any point in their adult lives. (This refers to the estrogen that the ovaries produce, not the estrogen used in hormone therapy.) Low estrogen levels before menopause can raise younger women’s risk for the disease. Causes of low estrogen levels in younger women can be mental stress or a problem with the function of the ovaries.

The causes of coronary microvascular disease and atherosclerosis are also considered risk factors for the disease.

Screening and Prevention

No specific studies have been done on how to prevent coronary microvascular disease.

Researchers don’t yet know how or in what way preventing coronary microvascular disease differs from preventing coronary heart disease. Coronary microvascular disease affects the tiny coronary arteries; coronary heart disease affects the large coronary arteries.

Taking action to control risk factors for heart disease can help prevent or delay coronary heart disease. You can’t control some risk factors, such as older age and family history of heart disease. However, you can take steps to prevent or control other risk factors, such as high blood pressure, overweight and obesity, high blood cholesterol, diabetes, and smoking.

Heart-healthy lifestyle changes and ongoing medical care can help you lower your risk for heart disease.

Heart-Healthy Lifestyle Changes

Your doctor may recommend heart-healthy lifestyle changes if you have coronary microvascular disease. Heart-healthy lifestyle changes include:

Heart-Healthy Eating

Your doctor may recommend a heart-healthy eating plan, which should include:

  • Fat-free or low-fat dairy products, such as skim milk
  • Fish high in omega-3 fatty acids, such as salmon, tuna, and trout, about twice a week
  • Fruits, such as apples, bananas, oranges, pears, and prunes
  • Legumes, such as kidney beans, lentils, chickpeas, black-eyed peas, and lima beans
  • Vegetables, such as broccoli, cabbage, and carrots
  • Whole grains, such as oatmeal, brown rice, and corn tortillas. 

When following a heart-healthy diet, you should avoid eating:

  • A lot of red meat
  • Palm and coconut oils
  • Sugary foods and beverages

Two nutrients in your diet make blood cholesterol levels rise:

  • Saturated fat—found mostly in foods that come from animals
  • Trans fat (trans fatty acids)—found in foods made with hydrogenated oils and fats, such as stick margarine; baked goods, such as cookies, cakes, and pies; crackers; frostings; and coffee creamers. Some trans fats also occur naturally in animal fats and meats.

Saturated fat raises your blood cholesterol more than anything else in your diet. When you follow a heart-healthy eating plan, only 5 percent to 6 percent of your daily calories should come from saturated fat. Food labels list the amounts of saturated fat. To help you stay on track, here are some examples:

If you eat:Try to eat no more than:

1,200 calories a day

 8 grams of saturated fat a day

1,500 calories a day

10 grams of saturated fat a day

1,800 calories a day

12 grams of saturated fat a day

2,000 calories a day

13 grams of saturated fat a day

2,500 calories a day

17 grams of saturated fat a day

Not all fats are bad. Monounsaturated and polyunsaturated fats actually help lower blood cholesterol levels.

Some sources of monounsaturated and polyunsaturated fats are:

  • Avocados
  • Corn, sunflower, and soybean oils
  • Nuts and seeds, such as walnuts
  • Olive, canola, peanut, safflower, and sesame oils
  • Peanut butter
  • Salmon and trout
  • Tofu

Sodium

You should try to limit the amount of sodium that you eat. This means choosing and preparing foods that are lower in salt and sodium. Try to use low-sodium and “no added salt” foods and seasonings at the table or while cooking. Food labels tell you what you need to know about choosing foods that are lower in sodium. Try to eat no more than 2,300 milligrams of sodium a day. If you have high blood pressure, you may need to restrict your sodium intake even more.

Dietary Approaches to Stop Hypertension

Your doctor may recommend the Dietary Approaches to Stop Hypertension (DASH) eating plan if you have high blood pressure. The DASH eating plan focuses on fruits, vegetables, whole grains, and other foods that are heart healthy and low in fat, cholesterol, and sodium and salt.

The DASH eating plan is a good heart-healthy eating plan, even for those who don’t have high blood pressure. Read more about DASH.

Alcohol

Try to limit alcohol intake. Too much alcohol can raise your blood pressure and triglyceride levels, a type of fat found in the blood. Alcohol also adds extra calories, which may cause weight gain.

Men should have no more than two drinks containing alcohol a day. Women should have no more than one drink containing alcohol a day. One drink is:

  • 12 ounces of beer
  • 5 ounces of wine
  • 1½ ounces of liquor

Maintaining a Healthy Weight

Maintaining a healthy weight is important for overall health and can lower your risk for coronary heart disease. Aim for a Healthy Weight by following a heart-healthy eating plan and keeping physically active.

Knowing your body mass index (BMI) helps you find out if you’re a healthy weight in relation to your height and gives an estimate of your total body fat. To figure out your BMI, check out the National Heart, Lung, and Blood Institute’s (NHLBI) online BMI calculator or talk to your doctor. A BMI:

  • Below 18.5 is a sign that you are underweight.
  • Between 18.5 and 24.9 is in the normal range.
  • Between 25 and 29.9 is considered overweight.
  • Of 30 or more is considered obese.

A general goal to aim for is a BMI below 25. Your doctor or health care provider can help you set an appropriate BMI goal.

Measuring waist circumference helps screen for possible health risks. If most of your fat is around your waist rather than at your hips, you’re at a higher risk for heart disease and type 2 diabetes. This risk may be high with a waist size that is greater than 35 inches for women or greater than 40 inches for men. To learn how to measure your waist, visit Assessing Your Weight and Health Risk

If you’re overweight or obese, try to lose weight. A loss of just 3 percent to 5 percent of your current weight can lower your triglycerides, blood glucose, and the risk of developing type 2 diabetes. Greater amounts of weight loss can improve blood pressure readings, lower LDL cholesterol, and increase HDL cholesterol.

Managing Stress

Research shows that the most commonly reported “trigger” for a heart attack is an emotionally upsetting event—particularly one involving anger. Also, some of the ways people cope with stress—such as drinking, smoking, or overeating—aren’t healthy.

Learning how to manage stress, relax, and cope with problems can improve your emotional and physical health. Consider healthy stress-reducing activities, such as:

  • A stress management program
  • Meditation
  • Physical activity
  • Relaxation therapy
  • Talking things out with friends or family

Physical Activity

Routine physical activity can lower many coronary heart disease risk factors, including LDL (“bad”) cholesterol, high blood pressure, and excess weight. Physical activity also can lower your risk for diabetes and raise your HDL cholesterol level. HDL is the “good” cholesterol that helps prevent coronary heart disease.

Everyone should try to participate in moderate-intensity aerobic exercise at least 2 hours and 30 minutes per week, or vigorous aerobic exercise for 1 hour and 15 minutes per week. Aerobic exercise, such as brisk walking, is any exercise in which your heart beats faster and you use more oxygen than usual. The more active you are, the more you will benefit. Participate in aerobic exercise for at least 10 minutes at a time spread throughout the week.

Read more about physical activity at:

Talk with your doctor before you start a new exercise plan. Ask your doctor how much and what kinds of physical activity are safe for you.

Quitting Smoking

If you smoke, quit. Smoking can raise your risk for coronary heart disease and heart attack and worsen other coronary heart disease risk factors. Talk with your doctor about programs and products that can help you quit smoking. Also, try to avoid secondhand smoke.

If you have trouble quitting smoking on your own, consider joining a support group. Many hospitals, workplaces, and community groups offer classes to help people quit smoking.

Read more about quitting smoking at Smoking and Your Heart.

Ongoing Medical Care

Learn more about heart disease and the traits, conditions, and habits that can raise your risk for developing it. Talk with your doctor about your risk factors for heart disease and how to control them.

If lifestyle changes aren’t enough, your doctor may prescribe medicines to control your risk factors. Take all of your medicines as your doctor advises. Visit your doctor regularly and have recommended testing.

Know your numbers. Ask your doctor for these three tests and have the results explained to you:

  • Blood pressure measurement.
  • Fasting blood glucose. This test is for diabetes.
  • Lipoprotein panel. This test measures total cholesterol, LDL (“bad”) cholesterol, HDL (“good”) cholesterol, and triglycerides (a type of fat in the blood).

Finally, know your family history of heart disease. If you or someone in your family has heart disease, tell your doctor.

Signs, Symptoms, and Complications

The signs and symptoms of coronary microvascular disease (MVD) often differ from the signs and symptoms of traditional coronary heart disease (CHD).

Many women with coronary MVD have angina (an-JI-nuh or AN-juh-nuh). 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.

Angina also is a common symptom of CHD. However, the angina that occurs in coronary MVD may differ from the typical angina that occurs in CHD. In coronary MVD, the chest pain usually lasts longer than 10 minutes, and it can last longer than 30 minutes. Typical angina is more common in women older than 65.

Other signs and symptoms of coronary MVD are shortness of breath, sleep problems, fatigue (tiredness), and lack of energy.

Coronary MVD symptoms often are first noticed during routine daily activities (such as shopping, cooking, cleaning, and going to work) and times of mental stress. It's less likely that women will notice these symptoms during physical activity (such as jogging or walking fast).

This differs from CHD, in which symptoms often first appear while a person is being physically active—such as while jogging, walking on a treadmill, or going up stairs.

Diagnosis

Your doctor will diagnose coronary microvascular disease (MVD) based on your medical history, a physical exam, and test results. He or she will check to see whether you have any risk factors for heart disease.

For example, your doctor may measure your weight and height to check for overweight or obesity. He or she also may recommend tests for high blood cholesterol, metabolic syndrome, and diabetes.

Your doctor may ask you to describe any chest pain, including when it started and how it changed during physical activity or periods of stress. He or she also may ask about other symptoms, such as fatigue (tiredness), lack of energy, and shortness of breath. Women may be asked about their menopausal status.

Specialists Involved

Cardiologists and doctors who specialize in family and internal medicine might help diagnose and treat coronary MVD. Cardiologists are doctors who specialize in diagnosing and treating heart diseases and conditions.

Diagnostic Tests

The risk factors for coronary MVD and traditional coronary heart disease (CHD) often are the same. Thus, your doctor may recommend tests for CHD, such as:

  • Coronary angiography (an-jee-OG-rah-fee). This test uses dye and special
    x rays to show the insides of your coronary arteries. Coronary angiography can show plaque buildup in the large coronary arteries. This test often is done during a heart attack to help find blockages in the coronary arteries.
  • Stress testing. This test shows how blood flows through your heart during physical stress, such as exercise. Even if coronary angiography doesn't show plaque buildup in the large coronary arteries, a stress test may still show abnormal blood flow. This may be a sign of coronary MVD.
  • Cardiac MRI (magnetic resonance imaging) stress test. Doctors may use this test to evaluate people who have chest pain.

Unfortunately, standard tests for CHD aren't designed to detect coronary MVD. These tests look for blockages in the large coronary arteries. Coronary MVD affects the tiny coronary arteries.

If test results show that you don't have CHD, your doctor might still diagnose you with coronary MVD. This could happen if signs are present that not enough oxygen is reaching your heart's tiny arteries.

Coronary MVD symptoms often first occur during routine daily tasks. Thus, your doctor may ask you to fill out a questionnaire called the Duke Activity Status Index (DASI). The questionnaire will ask you how well you're able to do daily activities, such as shopping, cooking, and going to work.

The DASI results will help your doctor decide which kind of stress test you should have. The results also give your doctor information about how well blood is flowing through your coronary arteries.

Your doctor also may recommend blood tests, including a test for anemia. Anemia is thought to slow the growth of cells needed to repair damaged blood vessels.

Research is ongoing for better ways to detect and diagnose coronary MVD. Currently, researchers have not agreed on the best way to diagnose the disease.

Treatment

Relieving pain is one of the main goals of treating coronary microvascular disease (MVD). Treatments also are used to control risk factors and other symptoms. Treatments may include medicines, such as:

  • ACE inhibitors and beta blockers to lower blood pressure and decrease the heart’s workload
  • Aspirin to help prevent blood clots or control inflammation
  • Nitroglycerin to relax blood vessels, improve blood flow to the heart muscle, and treat chest pain
  • Statin medicines to control or lower your blood cholesterol.

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.

If you’re diagnosed with coronary MVD and also have anemia, you may benefit from treatment for that condition. Anemia is thought to slow the growth of cells needed to repair damaged blood vessels.

If you’re diagnosed with and treated for coronary MVD, you should get ongoing care from your doctor. Research is under way to find the best treatments for coronary MVD.

Living With

If you have coronary microvascular disease (MVD), you can take action to control it. Follow the steps described in "How Can Coronary Microvascular Disease Be Prevented?"

Coronary MVD, like traditional coronary heart disease, increases your risk for a heart attack. If you have signs or symptoms of a heart attack, call 9–1–1 at once.

These signs and symptoms may include chest pain, upper body discomfort, shortness of breath, and nausea (feeling sick to your stomach). For more detailed information about the warning signs of a heart attack, go to the section on warning signs below.

Ongoing Care

If you have coronary MVD, see your doctor regularly to make sure the disease isn't getting worse. Work with your doctor to keep track of your cholesterol, blood pressure, and blood sugar levels. This will help your doctor adjust your treatment as needed.

You may need to see a cardiologist (heart specialist) in addition to your primary care doctor. Talk with your doctor about how often you should schedule office visits or blood tests. Between those visits, call your doctor if you have any new symptoms or your symptoms worsen.

You should:

  • Know your symptoms and how and when to seek medical help.
  • Be able to describe the usual pattern of your symptoms.
  • Know which medicines you take and when and how to take them.
  • Know how to control your symptoms, including angina.
  • Know the limits of your physical activity.
  • Learn ways to avoid or cope with stress.

Warning Signs

If you have coronary MVD, learn the warning signs of a heart attack. The signs and symptoms of a heart attack include:

  • Chest pain or discomfort. This involves uncomfortable pressure, squeezing, fullness, or pain in the center or left side of the chest that can be mild or strong. This pain or discomfort often lasts more than a few minutes or goes away and comes back.
  • Upper body discomfort in one or both arms, the back, neck, jaw, or upper part of the stomach.
  • Shortness of breath, which may occur with or before chest discomfort.
  • Nausea (feeling sick to your stomach), vomiting, light-headedness or fainting, or breaking out in a cold sweat.
  • Sleep problems, fatigue (tiredness), and lack of energy.

If you think you're having a heart attack, call 9–1–1 at once. Early treatment can prevent or limit damage to your heart muscle. Do not drive to the hospital or let someone else drive you. Instead, call an ambulance so that medical personnel can begin life-saving treatment on the way to the emergency room.

Let the people you see regularly know you're at risk for a heart attack. They can seek emergency care if you suddenly faint, collapse, or have other severe symptoms.

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