Coronary Microvascular Disease


Consider this scenario: You're admitted to a hospital with angina (chest pain). You undergo an X-ray imaging test called an angiogram to see if you have blockages in the arteries that supply blood to your heart. The test is clear, but you have been experiencing angina. A stress test finds that portions of your heart aren’t receiving enough oxygen-rich blood. Both you and your doctor know that something is wrong. Now what?

Scenarios like this are common in individuals who might have coronary microvascular disease (also known as small vessel disease). As the name implies, this is a disease of the smaller (micro) blood vessels (vascular) that are 100–200 micrometers in diameter (a human hair is roughly 100 micrometers in diameter) and supply the heart with blood. In patients with coronary microvascular disease, blood doesn’t flow properly through these tiny blood vessels. The heart muscle may not have enough oxygen-rich blood, or oxygen may be cut off entirely to portions of the heart muscle. While microvascular disease can be present in men* (assigned male at birth) and women* (assigned female at birth), it’s more common in women1, and it’s one of the factors that can make heart disease in women harder to diagnose.

What medical professionals now know about heart disease in women who don’t have blockages in the coronary arteries is thanks to a National Heart, Lung, and Blood Institute (NHLBI) study started in 1996. Research from this study called the Women’s Ischemia Syndrome Evaluation (WISE) identified microvascular disease as one reason some diagnostic tests may not show women’s heart disease.

In addition to problems with the tiny blood vessels in the heart, microvascular disease can be caused by high blood pressure or issues with the heart muscle or heart valves. Your doctor may arrange an echocardiogram (heart ultrasound) to check for abnormalities.

Medical researchers are still working to understand microvascular disease and why it’s more prevalent in women. Researchers are exploring whether a drop in the hormone estrogen after menopause may play a role in the development of coronary microvascular disease.

Why coronary microvascular disease matters

The effects of coronary microvascular disease on women’s health are substantial:

  • Even without evidence of blockages in the major heart arteries, women with ongoing chest pain have high five-year rates of cardiovascular events such as heart attacks. This might be due to coronary microvascular disease among these women. Further research studies are needed to understand this condition better.
  • Many women with chest pain or suspected reduced blood flow to the heart don’t have blockages in the major coronary arteries, making their heart disease more challenging to diagnose for the treating heart specialist.
  • Women with symptoms of heart disease but no blockages in the major arteries have a higher risk for depression and a lower quality of life.
  • Coronary microvascular disease may contribute to the later development of coronary artery disease (CAD), which occurs when there are blockages in the larger arteries that supply the heart with blood.

*The term “women” in the context of “women’s cardiovascular health” applies to individuals assigned female at birth (AFAB) who have a female biological reproductive system, which includes a vagina, uterus, ovaries, Fallopian tubes, accessory glands, and external genital organs.

*The term “men” in the context of “cardiovascular health” applies to individuals assigned male at birth (AMAB) who have a male biological reproductive system, which includes a penis, scrotum, testes, epididymis, vas deferens, prostate, and seminal vesicles.

Black female doctor showing digital tablet to senior patient

Women's Cardiovascular Health

It's important for women to learn about their cardiovascular health, as women overall seem to have poorer outcomes from heart disease treatment than men.