Microvascular Coronary Disease (Small Vessel Disease)

What is coronary microvascular disease (small vessel disease)?

Microvascular disease affects arteries that branch off from your heart’s main blood vessels (coronary microvasculature).

It’s also known as:

• Small artery disease.
• Small vessel disease.
• Cardiac X syndrome.
• Microvessel disease.
• Nonobstructive coronary heart disease.

What is the role of the coronary microvasculature?

The coronary microvasculature is a network of tiny blood vessels in your heart. Many of them are the size of a few human hairs. These vessels control blood flow and capillary exchange within your heart.

Capillary exchange is a complex process during which tiny vessels deliver oxygen-rich blood and receive oxygen-poor blood from nearby tissue. The exchange also involves gases, nutrients and waste products.

How is coronary microvascular disease different from coronary artery disease?

Both conditions raise your risk of a heart attack. But the ways they affect your heart are different:

• Coronary artery disease impacts the larger vessels called coronary arteries that overlay your heart. This condition most commonly occurs when fatty deposits (plaques) that form inside your arteries reduce or block blood flow completely.
• Coronary microvascular disease affects the microvasculature (small blood vessels that come off of the large blood vessels) and prevents blood from nourishing your heart tissue. It occurs due to blood vessel damage or malfunction of the small blood vessels, not plaque buildup.

Who is more likely to experience microvascular coronary disease?

Small vessel disease is more likely to affect women than men. This is especially true in people with low estrogen levels, which occurs around menopause.

Other risk factors for include:

• Autoimmune disease, including vasculitis.
• Having overweight/obesity.
• Diabetes.
• Eating a diet that’s high in salt, saturated fat and processed foods.
• High blood pressure.
• High cholesterol.
• Rheumatologic disorders, such as lupus or rheumatoid arthritis.
• Sedentary lifestyle with low levels of physical activity.
• Smoking.

What causes microvascular coronary disease?

The condition affects the smooth muscle function of your heart’s smallest arteries. In a healthy heart, these muscles narrow and widen to keep up with your heart’s changing needs. With coronary microvascular disease, damage occurs to the inner walls of small vessels. This damage can cause spasms that disrupt blood flow to your heart.

What are the symptoms of small vessel disease?

The primary symptom is a type of chest pain called angina that lasts 10 minutes or longer, even when resting. Pain may increase with mental stress and, less often, with physical exertion. Microvascular coronary disease symptoms can make it challenging to go about daily life.

Symptoms may also include:

• Fatigue.
• Shortness of breath.
• Sleep issues, including insomnia.

Chest pain can also be a symptom of a heart attack. Dial 911 or go to the closest emergency room if:

• You have chest pain that doesn't go away or gets worse.
• Chest pain is accompanied by other heart attack symptoms. These include difficulty breathing or pain that runs down your back, neck or arms.

How is coronary microvascular disease diagnosed?

Diagnosing microvascular heart disease is challenging because microvessels are too small to assess using standard heart tests. Seeing a cardiologist who specializes in small vessel disease can help you receive an accurate diagnosis and timely care.

Cardiac catheterization with coronary flow reserve (CFR) is the gold standard for diagnosing microvascular coronary disease. This sophisticated test measures the microvessel’s ability to quickly expand and deliver more blood based on your body’s needs.

Additional tests to measure coronary blood flow may include:

• Nuclear cardiac stress test (PET scan).
• Cardiac MRI with perfusion.

What treatments are available for patients with microvascular coronary disease?

Treatment often involves medications to help blood vessels work more effectively and lower the risk of complications.

Care may include:

• Angiotensin-converting-enzyme (ACE) inhibitors.
• Anticoagulants.
• Aspirin.
• Beta-blockers.
• Calcium channel blockers.
• Diuretics.
• Statins.

How can I prevent small vessel disease?

Taking good care of your heart can help you feel your best and lower the risk of complications. This includes:

• Being more physically active. You may benefit from cardiac rehab if you're new to exercising.
• Eating a heart-healthy diet.
• Keeping blood pressure within a healthy range.
• Maintaining a weight that's healthy for you.
• Quitting smoking.
• Reducing high blood sugar.

What is the outlook for people with small vessel disease?

With successful treatment, many people feel better and resume daily activities. You may need ongoing follow-up care to make sure therapies are working as they should.

What is living with microvascular heart disease like?

Taking medications and making lifestyle changes can take some getting used to. Some drugs cause unpleasant side effects, like feeling dizzy. It’s important to discuss these challenges with your healthcare provider. They can make recommendations or use other medications to help you get the most out of treatment.

Your healthcare provider may recommend keeping a daily record of symptoms and vital signs, like blood pressure. This information makes it easier to adjust treatments to your needs and preferences.

A note from Cleveland Clinic

Coronary microvascular disease happens when there’s a disruption of blood flow through the heart’s smallest blood vessels. Unlike coronary artery disease, which is due to a blockage, microvascular heart disease (small vessel disease) occurs when there’s blood vessel damage. The condition causes lasting chest pain and raises your heart attack risk. Medications and lifestyle changes help many people get symptom relief and avoid complications.