Endothelial Dysfunction

What is endothelial dysfunction?

Endothelial dysfunction affects your endothelium. This thin layer of cells lines the inside of blood vessels. Dysfunction means the cells don’t work the way they should. Instead of keeping blood vessels open (dilated), the cells cause your blood vessels to constrict or narrow.

The condition is caused by vasospasm — a type of coronary artery disease. This means your coronary arteries become narrow even though there isn’t a physical blockage. Endothelial dysfunction also increases the risk of coronary artery disease from atherosclerosis.

What does the endothelium do?

A single layer of endothelial cells lines the inside of all blood vessels (arteries, veins and capillaries), making your endothelium one of your body’s largest organ systems.

Endothelial cells secrete (release) substances that control the opening and closing of arteries (vascular tone). This vascular tone determines blood pressure and dictates how hard your heart has to work to pump blood.

Your endothelium also:

• Controls fluids and electrolytes in your blood.
• Helps your body clot blood when needed.
• Keeps toxins out of tissues.
• Regulates tissue inflammation.

How common is endothelial dysfunction?

For many years, health specialists thought the endothelium was merely a barrier in blood vessels. When they recognized it as an organ system, they were able to identify endothelial dysfunction as a distinct condition.

These discoveries occurred in the late 1990s. That means recognition of the condition is still fairly new. Experts aren’t yet sure how many people develop it.

What causes endothelial dysfunction?

Endothelial dysfunction occurs when there isn’t enough nitric oxide (NO) inside of your blood vessel walls. Your endothelium itself makes nitric oxide, which acts as a vasodilator, opening up your blood vessels for your blood to flow freely.

A drop in nitric oxide can lead to:

• Narrowed blood vessels, which can contribute to high blood pressure.
• Inflammation in your artery walls, which can lead to atherosclerosis.
• Increased platelet production, which causes blood clots.
• Porous blood vessel walls, which expose tissues to damaging lipoproteins and other toxic substances.

What are the symptoms of endothelial dysfunction?

Angina, or chest pain, is the main symptom of endothelial dysfunction in coronary arteries. This chest pain is the result of your arteries closing when they should be open. The chest pain is often worse during physical activity.

Some people develop continued angina even at rest, which can signal a heart attack. Symptoms include unrelenting chest pain, extreme fatigue and shortness of breath. This is a medical emergency that requires immediate treatment.

What are the risk factors for endothelial dysfunction?

Certain factors may increase your risk of endothelial dysfunction. Your risk is higher if you have:

• Diabetes.
• High blood pressure (hypertension).
• High blood sugar (hyperglycemia).
• High cholesterol.
• Metabolic syndrome.
• Smoking.
• Obesity.
• Certain autoimmune diseases.

What conditions are linked to endothelial dysfunction?

Endothelial dysfunction increases the risk of cardiovascular diseases and other conditions like:

• Atherosclerosis and coronary artery disease.
• Blood clots and strokes.
• Enlarged heart (hypertrophic cardiomyopathy).
• Heart attacks and heart failure.
• High blood pressure (hypertension).
• Kidney failure.
• Peripheral artery disease (PAD).
• Pulmonary hypertension (PH).
• Small vessel disease (coronary microvascular disease).

What are the complications of endothelial dysfunction?

Endothelial dysfunction can lead to acute coronary syndrome. This combination of three different types of coronary artery disease increases the risk of plaque rupturing inside a blood vessel. A ruptured plaque can block blood flow to your heart muscle, causing a heart attack.

How is endothelial dysfunction diagnosed?

Healthcare providers use imaging tests to view blood flow through blood vessels directly. These tests let your healthcare provider check for signs of endothelial dysfunction. These tests include:

• Electrocardiogram (EKG).
• Angiogram, including coronary computed tomography angiogram (CCTA).

They can also use certain types of stress imaging to see if there’s decreased blood flow through your blood vessels that cause decreased function in your heart. These imaging tests include:

• Echocardiogram (echo).
• MRI.
• Positron emission tomography (PET) scan.

How is endothelial dysfunction treated?

If you have coronary or peripheral artery disease due to endothelial dysfunction, your healthcare provider may also recommend medications, such as:

• Aspirin or medications to prevent blood clots.
• Blood pressure medicines like calcium channel blockers.
• Cholesterol-lowering drugs like statins.
• Nitrates to open up blood vessels.

If you have endothelial dysfunction, you can also minimize your symptoms with dietary and lifestyle changes. These include:

• Eating a heart-healthy diet and getting regular exercise.
• Limiting alcohol consumption.
• Losing weight (if needed) and maintaining a healthy weight.
• Finding healthy ways to manage stress.
• Getting help to quit smoking and avoiding secondhand smoke.
• Managing conditions like high blood pressure, diabetes and high cholesterol.

What is the outlook for people with endothelial dysfunction?

Endothelial dysfunction is highly treatable with proper lifestyle changes and medications. However, some people with nonobstructive coronary artery disease continue to have chest pain despite treatments.

Chronic chest pain can interfere with daily activities. It may lead to anxiety and depression. Psychotherapy, medication and stress management techniques can help.

When should I call the doctor?

Call your healthcare provider if you experience:

• Chest pain.
• Shortness of breath.
• Signs of a heart attack.
• Unexplained fatigue.

What should I ask my provider?

You may want to ask your healthcare provider:

• What caused the endothelial dysfunction?
• Do I need medications?
• What lifestyle and dietary changes should I make?
• Am I at risk for heart disease? How can I lower this risk?
• Should I look out for signs of complications?

A note from Cleveland Clinic

Endothelial dysfunction is a type of coronary artery disease. A lack of nitric oxide gas inside of your blood vessel walls causes arteries to narrow. This narrowing slows blood flow to your heart. The condition causes angina (chest pain) and increases your risk of heart conditions. Experienced healthcare providers can identify symptoms and perform imaging tests to make a diagnosis. You can make lifestyle and dietary changes and take medications to treat endothelial dysfunction. These steps can lower your risk of serious heart problems.