Overview

Renal artery stenosis is when one or more arteries that carry blood to the kidneys narrow. These are called the renal arteries.

Having narrowed renal arteries means the kidneys don't get enough oxygen-rich blood. The kidneys need enough blood flow to help filter waste products and remove excess fluids. Less blood flow to the kidneys may injure kidney tissue and raise blood pressure throughout the body.

Symptoms

Renal artery stenosis often doesn't cause symptoms until it's advanced. A healthcare professional may find the condition while testing for something else. Or your healthcare professional may suspect the condition if you have:

  • High blood pressure that begins suddenly or gets worse without a known cause.
  • High blood pressure that begins before age 30 or after age 55.

As renal artery stenosis advances, other signs and symptoms may include:

  • High blood pressure that's hard to manage.
  • A whooshing sound as blood flows through a narrowed vessel, called a bruit. A member of your healthcare team hears the sound through a stethoscope placed over your kidneys.
  • Fluid buildup and swelling in the body's tissues.

When to see a doctor

Make an appointment with your healthcare professional if you have lasting symptoms that worry you.

Causes

The two main causes of renal artery stenosis include:

  • Buildup on kidney arteries, also called renal arteries. Fats, cholesterol and other substances, called plaques, can build up in and on the kidney artery walls. This is called atherosclerosis.

    As the buildup grows, the plaque can harden. That lowers blood flow and causes kidney scarring. In time, the plaque narrows the artery. Atherosclerosis happens in many areas of the body. It's the most common cause of renal artery stenosis.

  • Fibromuscular dysplasia. In fibromuscular dysplasia, the muscle in the artery wall doesn't grow as it should. This often begins in childhood. The renal artery can have narrow sections and wider sections. This looks like beads in images of the artery.

    The renal artery can narrow so much that the kidney doesn't get enough blood. This 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 people assigned female at birth. It may be present at birth, called congenital.

Risk factors

Most often, renal artery stenosis results from narrowed kidney arteries. Risk factors for narrowed arteries in the kidneys and other parts of the body include:

  • Older age.
  • High blood pressure.
  • High cholesterol.
  • Diabetes.
  • Obesity.
  • Smoking and other tobacco use.
  • A family history of early heart disease.
  • Lack of exercise.

Complications

Possible complications of renal artery stenosis include:

  • High blood pressure.
  • Chronic kidney disease or kidney failure. Kidney disease can happen if high blood pressure is not managed over time. Kidney failure needs treatment with dialysis or a kidney transplant.
  • Fluid retention in the legs. This causes swollen ankles or feet.
By Mayo Clinic Staff