Microangiopathy

Microangiopathy (or microvascular disease, or small vessel disease) is an angiopathy (i.e.disease of blood vessels) affecting small blood vessels in the body. It can be contrasted to macroangiopathy.

The term cerebral small vessel disease refers to a group of pathological processes with various aetiologies that affect the small arteries, arterioles, venules, and capillaries of the brain. Age-related and hypertension-related small vessel diseases and cerebral amyloid angiopathy are the most common forms.

Small vessel coronary disease is a type of coronary heart disease (CHD) that affects the heart's arterioles and capillaries. Small vessel coronary disease is also known as cardiac syndrome X, microvascular dysfunction, non-obstructive coronary disease, or microvascular angina.

Pathophysiology

One cause of microangiopathy is long-term diabetes mellitus. In this case, high blood glucose levels cause the endothelial cells lining the blood vessels to take in more glucose than normal (these cells do not depend on insulin). They then form more glycoproteins on their surface than normal, and also cause the basement membrane to grow thicker and weaker. The walls of the vessels become abnormally thick but weak, and therefore they bleed, leak protein, and slow the flow of blood through the body. Then some cells, for example in the retina (diabetic retinopathy) or kidney (diabetic nephropathy), may not get enough blood and may be damaged. Nerves, if not sufficiently supplied with blood, are also damaged which may lead to loss of function (diabetic neuropathy).