Appointments & care

At Mayo Clinic, we take the time to listen, to find answers and to provide you the best care.

Renal artery stenosis is the narrowing of one or more arteries that carry blood to your kidneys (renal arteries).

Narrowing of the arteries prevents normal amounts of oxygen-rich blood from reaching your kidneys. Your kidneys need adequate blood flow to help filter waste products and remove excess fluids. Reduced blood flow may increase blood pressure in your whole body (systemic blood pressure) and injure kidney tissue.

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Renal artery stenosis may cause no signs or symptoms until the condition reaches an advanced state. Most people with renal artery stenosis have no signs and symptoms. The condition may be discovered incidentally during testing for some other reason. Your doctor may also suspect a problem if you have:

• High blood pressure that begins suddenly
• High blood pressure that begins before age 30 or after age 55

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

• High blood pressure that's difficult to treat
• A whooshing sound as blood flows through a narrowed vessel (bruit), which your doctor hears through a stethoscope placed over your kidneys
• Elevated protein levels in the urine or other signs of abnormal kidney function
• Worsening kidney function during treatment for high blood pressure
• Fluid overload and swelling in your body's tissues
• Treatment-resistant heart failure

When to seek medical advice

Make an appointment with your doctor if you have any persistent signs or symptoms that worry you.

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The two main causes of renal artery stenosis include:

• Atherosclerosis of the renal arteries. Atherosclerosis is the buildup of fats, cholesterol and other substances (plaques) in and on your artery walls. As the deposits get larger, they can harden, reduce blood flow and cause scarring of the kidney. Eventually, narrowing of the artery can result. Most cases of renal artery stenosis occur because of atherosclerosis.
• Fibromuscular dysplasia. In fibromuscular dysplasia, the muscle in the artery wall grows abnormally. The renal artery can have narrow sections alternating with wider sections, giving a beadlike appearance in images of the artery. The renal artery can narrow so much that the kidney doesn't receive an adequate supply of blood and can become damaged. 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).

Atherosclerosis and fibromuscular dysplasia can affect other arteries in your body as well as your kidney (renal) arteries and cause complications.

Rarely, renal artery stenosis results from other conditions such as inflammation of the blood vessels (vasculitis); a nervous system disorder that causes tumors to develop on nerve tissue (neurofibromatosis); or a growth that develops in your abdomen and presses on your kidneys' arteries (extrinsic compression).

Source: http://www.mayoclinic.com

Appointments & care

At Mayo Clinic, we take the time to listen, to find answers and to provide you the best care.

For diagnosis of renal artery stenosis, your doctor may start with:

• A physical exam that includes your doctor listening through a stethoscope over the kidney areas for sounds that may mean the artery to your kidney is narrowed
• A review of your medical history
• Blood and urine tests to check your kidney function
• Blood and urine tests to measure the levels of hormones that regulate blood pressure

Imaging tests commonly done to diagnose renal artery stenosis include:

• Doppler ultrasound. High-frequency sound waves help your doctor see the arteries and kidneys and check their function. This procedure also helps your doctor find blockages in the blood vessels.
• Computerized tomography (CT) scan. During a CT scan, an X-ray machine linked to a computer creates a detailed image that shows cross-sectional images of the renal arteries. You may receive a dye injection to show blood flow.
• Magnetic resonance angiography (MRA). MRA uses radio waves and strong magnetic fields to produce detailed 3-D images of the renal arteries and kidneys. A dye injection into the arteries outlines blood vessels during imaging.
• Renal arteriography. This special type of X-ray exam helps your doctor check blood flow and find the blockage in the renal arteries. Before an X-ray is taken, your doctor injects a dye into the renal arteries through a long, thin tube (catheter) to outline the arteries and show blood flow more clearly. This test is often performed at the time of restoring the blood vessel opening with a stent.

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Possible complications of renal artery stenosis include:

• High blood pressure (renovascular hypertension)
• Kidney failure, requiring treatment with dialysis or a kidney transplant
• Fluid retention (edema) in your legs, causing swollen ankles or feet
• Shortness of breath due to sudden buildup of fluid in the lungs (flash pulmonary edema)

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As a part of your treatment plan for renal artery stenosis, your doctor may recommend making certain lifestyle changes:

• Maintain a healthy weight. When your weight increases, so does your blood pressure. If you're overweight, even losing 10 pounds may help to lower your blood pressure.
• Restrict salt in your diet. Salt and salty foods cause your body to retain fluid. This may increase the volume of your blood and, in turn, increase your blood pressure.
• Be physically active. Being physically active on a regular basis may help you lose weight, lower your risk of heart disease, lower your cholesterol and lower your blood pressure. Check with your doctor before beginning an exercise program, especially if you have high blood pressure and haven't been active in the past.
• Reduce stress. Stress can increase your blood pressure temporarily. This increase varies, depending on your level of stress and how your body reacts to it.
• Drink alcohol in moderation, if at all. Too much alcohol may increase your blood pressure.
• Don't smoke. Tobacco injures blood vessel walls and speeds up the process of hardening of the arteries. If you smoke, ask your doctor to help you quit.

Source: http://www.mayoclinic.com

Most cases of renal artery stenosis result from atherosclerosis. Risk factors for atherosclerosis of the renal arteries are the same as for atherosclerosis anywhere else in your body and include:

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

Source: http://www.mayoclinic.com