Causes

The two main causes of renal artery stenosis include:

• Buildup on kidney (renal) arteries. Fats, cholesterol and other substances (plaque) can build up in and on your kidney artery walls (atherosclerosis). As these deposits get larger, they can harden, reduce blood flow, cause kidney scarring and eventually narrow the artery. Atherosclerosis occurs in many areas of the body and is the most common cause of renal artery stenosis.

• Fibromuscular dysplasia. In fibromuscular dysplasia, the muscle in the artery wall grows abnormally, often from childhood. The renal artery can have narrow sections alternating with wider sections, giving a bead-like appearance in images of the artery.

  The renal artery can narrow so much that the kidney doesn't get an adequate supply of blood and can lead to high blood pressure at a young age. This can happen in one or both kidneys. Experts don't know what causes fibromuscular dysplasia, but the condition is more common in women and may be something that's present at birth (congenital).

Narrowed kidney arteries and fibromuscular dysplasia can affect other arteries in your body as well as your kidney arteries and cause complications.

Rarely, renal artery stenosis results from other conditions such as inflammation of the blood vessels or a growth that develops in your abdomen and presses on your kidneys' arteries.