Clinical Definition

Microvascular coronary dysfunction is a cardiovascular condition that affects the capillaries and arterioles connected to the myocardium. Microvascular dysfunction interferes with proper dilation of the small vessels carrying oxygen to the myocardium. Ischemia and angina may develop as a result of microvascular coronary dysfunction.

In Our Own Words

The heart pumps blood to the body through the aorta, but also saves some oxygen-rich blood for itself, which travels through the coronary arteries. The coronary arteries branch off into smaller arterioles and capillaries. When a person has microvascular coronary dysfunction (small vessel disease), the capillaries and arterioles that feed the heart do not open up and get wider as they should when blood flows through them.

Diseased vessels may even contract during exercise or increased demand on the heart. This poor functioning of the small vessels restricts blood flow and can cause symptoms just like the more widely known “obstructive” coronary artery disease that’s caused by a blockage. Small vessel disease may be more common in women and may be associated with heart attacks with atypical symptoms.