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.

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.

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).

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

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)

For renal artery stenosis, you may start by seeing your family doctor or a general practitioner. However, you may be referred to a doctor who specializes in conditions that affect the heart and blood vessels (cardiologist) or kidneys (nephrologist).

Here's some information to help you get ready for your appointment as well as what to expect from your doctor.

What you can do

To prepare for your appointment:

  • Write down symptoms you have, including any that may seem unrelated to the reason for which you scheduled the appointment.
  • Make a list of all medications, vitamins and supplements that you take, including dosages.
  • Be prepared to report key medical information to your doctor, including past or current smoking or use of other tobacco products.
  • Ask a family member or friend to come along. Sometimes it can be difficult to remember all of the information provided to you during an appointment. Someone who accompanies you may remember something that you missed or forgot.
  • Write down questions to ask your doctor.

For renal artery stenosis, some basic questions to ask your doctor include:

  • What's the most likely cause of my symptoms?
  • Are there any other possible causes for my symptoms?
  • What kinds of tests do I need? Do these tests require any special preparation?
  • Is this condition temporary or long lasting?
  • What treatments are available, and which do you recommend?
  • What side effects can I expect from treatment?
  • I have other health conditions. How can I best manage them together?
  • Do I need to follow any dietary restrictions? What about activity restrictions?
  • Is there a generic alternative to the medicine you're prescribing for me?
  • What's the appropriate level for my blood pressure? Is there anything I can do to help bring it down?
  • Do you have any printed material that I can take with me? What websites do you recommend?

In addition to the questions that you've prepared, don't hesitate to ask other questions as they occur to you during your appointment.

What to expect from your doctor

Your doctor is likely to ask you a number of questions, such as:

  • When did you first begin experiencing symptoms?
  • Are you a current or past smoker, or do you use any other type of tobacco products?
  • Does anything seem to improve or worsen your symptoms?
  • Do you know your average blood pressure values?
  • Have you had your kidney function measured?
  • Does anyone in your family have a history of high blood pressure or kidney disease?

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.

Treatment for renal artery stenosis may involve lifestyle changes, medication or a procedure. Sometimes a combination of treatments is the best approach. Depending on your overall health and symptoms, observation may be all that you need.

Lifestyle changes

If your blood pressure is moderately or severely elevated, you may need to make certain lifestyle changes, such as:

  • Maintain a healthy weight or lose weight if you're overweight
  • Eat healthy foods
  • Limit salt in your diet
  • Be physically active
  • Reduce your stress levels
  • Drink alcohol or caffeinated beverages in moderation, if at all
  • Don't smoke

Medication

High blood pressure — even when mainly related to renal artery stenosis — often can be successfully treated with medications. Finding the right medication or combination of medications may require time and patience.

Some medications commonly used to treat high blood pressure associated with renal artery stenosis include:

  • Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs), which help relax your blood vessels and block the formation or effects of a natural body chemical called angiotensin II, which narrows blood vessels.
  • Diuretics, also known as water pills, which help your body eliminate excess sodium and water.
  • Beta blockers and alpha-beta blockers, which may have the effect of making your heart beat slowly and less forcefully or widening (dilating) your blood vessels, depending on which medication you use.
  • Calcium channel blockers, which help relax blood vessels.

If atherosclerosis is the underlying cause of renal artery stenosis, your doctor may also recommend aspirin and a cholesterol-lowering medication. Which medications are best for you depends on your individual situation.

Procedures

For certain people — for instance, those with uncontrolled high blood pressure and a complication such as pulmonary edema or worsening kidney function — a procedure may be recommended to restore blood flow through the renal artery and improve blood flow (perfusion) to the kidney.

Procedures to treat renal artery stenosis may include:

  • Renal angioplasty and stenting. In this procedure, doctors open wider the narrowed renal artery and place a device inside your blood vessel that holds the walls of the vessel open and allows for better blood flow.
  • Renal artery bypass surgery. During a bypass procedure, doctors graft a substitute blood vessel to the renal artery to make a new route for blood to reach your kidneys. Sometimes this means connecting the renal artery to a vessel from somewhere else, such as the liver or spleen.
  • Renal endarterectomy. This procedure involves removing the buildup of fats, cholesterol and other substances (plaques) from the renal artery and may be done during surgery to repair the aorta.

Recent results from clinical trials that compared renal angioplasty and stenting with medication alone didn't show a difference between the two treatment approaches on reducing high blood pressure and improving kidney function.

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.

Doctors at Mayo Clinic provide many diagnosis and treatment options for renal artery stenosis. Mayo Clinic is one of the largest kidney disease treatment centers in the United States.

Doctors trained in kidney diseases and high blood pressure (nephrology and hypertension) vascular and endovascular surgery, diagnostic and therapeutic (interventional) radiology, heart and blood vessel diseases (cardiovascular diseases), and vascular medicine work together to evaluate and treat each person.

At Mayo Clinic, we assemble a team of specialists who take the time to listen and thoroughly understand your health issues and concerns. We tailor the care you receive to your personal health care needs. You can trust our specialists to collaborate and offer you the best possible outcomes, safety and service.

Mayo Clinic is a not-for-profit medical institution that reinvests all earnings into improving medical practice, research and education. We're constantly involved in innovation and medical research, finding solutions to improve your care and quality of life. Your doctor or someone on your medical team is likely involved in research related to your condition.

Our patients tell us that the quality of their interactions, our attention to detail and the efficiency of their visits mean health care — and trusted answers — like they've never experienced.

Why Choose Mayo Clinic

What Sets Mayo Clinic Apart

Diagnosis at Mayo Clinic begins with:

  • A physical exam that includes your doctor listening through a stethoscope for sounds that may mean the artery to your kidney is narrowed
  • Questions about your medical and family history
  • Blood tests to evaluate kidney function and exclude other conditions

Doctors who specialize in the interpretation of medical images (radiologists) conduct tests to check your blood vessels and kidneys. You may need one or more of the following imaging tests to find the narrowing in the renal artery and determine how severe it is:

  • 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.
  • Specialized testing to evaluate oxygen delivery to the kidney. Blood oxygen level dependent (BOLD) magnetic resonance imaging evaluates how much oxygen your affected kidneys are receiving to determine whether restoring blood flow in your kidneys' arteries may be of benefit.
  • 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 is often performed at the time of restoring the blood vessel opening with a stent.

Read more about CT scan and ultrasound.

If a renal artery is narrowed or blocked, your doctor will talk with you about your treatment options. Treatment depends on the cause of the blockage and severity of your blood pressure and kidney dysfunction. Mayo Clinic doctors work to reduce your risk of kidney failure, improve blood pressure and relieve narrowing in the renal arteries.

Lifestyle changes, blood pressure medications and other medications to control cardiovascular risk factors can help some people prevent or slow the development of renal artery stenosis. Lifestyle changes such as eating healthy, being physically active and stopping smoking are also important parts of treatment.

Surgery

When lifestyle changes and medications aren't enough to manage renal artery stenosis, you may need repair of the arteries (revascularization) to restore blood flow to your kidneys.

Revascularization options include:

  • Renal angioplasty and stenting. This procedure opens the narrowed arteries. During an angioplasty, your doctor threads a long, thin tube (catheter) through an artery to the affected area. The doctor inflates a balloon on the tip of the catheter and flattens the fat and cholesterol buildup (plaques) onto the artery walls. In most cases, your doctor also will place a small wire tube (stent) to keep your artery open.
  • Renal artery bypass. You may need open surgery if you have severe renal artery stenosis that isn't receptive to stenting or if stenting has failed. During a bypass, your doctor grafts a substitute artery to the renal artery to make a new route for blood to reach your kidneys.
  • Renal endarterectomy. This procedure involves removing plaques in the renal arteries. Your doctor makes an incision in the aorta to remove the plaque from the renal artery, then stitches closed the aortic incision.

In some cases, careful management and observation may be all you need.

Mayo Clinic works with hundreds of insurance companies and is an in-network provider for millions of people. In most cases, Mayo Clinic doesn't require a physician referral. Some insurers require referrals or may have additional requirements for certain medical care. All appointments are prioritized on the basis of medical need.

At Mayo Clinic, specialists from the Vascular Center work with specialists trained in interventional radiology, kidney diseases and high blood pressure (nephrology and hypertension), and heart and blood vessel diseases (cardiovascular diseases) to diagnose and treat people with renal artery stenosis.

For appointments or more information, call the Central Appointment Office at 800-446-2279 (toll-free) 8 a.m. to 5 p.m. Mountain Standard Time, Monday through Friday or complete an online appointment request form.

At Mayo Clinic, specialists from the Vascular Center work with specialists trained in interventional radiology, kidney diseases and high blood pressure (nephrology and hypertension), and heart and blood vessel diseases (cardiovascular diseases) to diagnose and treat people with renal artery stenosis.

For appointments or more information, call the Central Appointment Office at 904-953-0853 8 a.m. to 5 p.m. Eastern time, Monday through Friday or complete an online appointment request form.

At Mayo Clinic, the Gonda Vascular Center brings together the expertise of doctors trained in interventional radiology, kidney diseases and high blood pressure (nephrology and hypertension), heart and blood vessel diseases (cardiovascular diseases), vascular and endovascular surgery, and heart surgery (cardiac surgery) to diagnose and treat people with renal artery stenosis. In addition, doctors in the Cardiovascular Health Clinic offer evaluation and preventive services to help you lessen your risk of blood vessel diseases such as renal artery stenosis.

For appointments or more information, call the Central Appointment Office at 507-538-3270 7 a.m. to 6 p.m. Central time, Monday through Friday or complete an online appointment request form.

See information on patient services at the three Mayo Clinic locations, including transportation options and lodging.

Doctors at Mayo Clinic have a long-standing interest in research related to renal artery stenosis. Findings from research studies can lead to new and improved treatments. Current research efforts focus on:

  • Assessing the most effective renal artery stenosis treatments
  • Exploring how renal artery stenosis develops
  • Determining the most appropriate treatment for people who have high blood pressure caused by renal artery stenosis
  • Increasing recovery of kidney function after treatment
  • Exploring new methods of boosting kidney repair after restoring blood flow

Researchers at Mayo Clinic are studying new diagnostic tools such as the multidetector computerized tomography (CT) scan and blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI). Mayo Clinic researchers developed these imaging tools, which use 3-D images to assess kidney function. BOLD MRI can show whether your kidney is getting sufficient oxygen and can recover after renal revascularization.

Current clinical trials underway include repair of injured kidney tissue with the administration of a person's own mesenchymal stem cells and the use of investigational protective agents (mitochondrial protection) at the time of revascularization.

Publications

See a list of publications from Mayo Clinic doctors on renal artery stenosis on PubMed, a service of the National Library of Medicine.

April 30, 2015