Renal Artery Stenosis

Overview

Renal artery stenosis is the narrowing of one or more arteries that carry blood to your kidneys (renal arteries). Narrowing of the arteries prevents enough 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 to your kidneys may injure kidney tissue and increase blood pressure throughout your body.

Symptoms

Renal artery stenosis often doesn't cause any signs or symptoms until it's advanced. The condition may be discovered incidentally during testing for something else. Your health care provider may also suspect a problem if you have:

1.High blood pressure that begins suddenly or worsens without explanation

2.High blood pressure that begins before age 30 or after age 50

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

1.High blood pressure that's hard to control

2.A whooshing sound as blood flows through a narrowed vessel (bruit), which your doctor hears through a stethoscope placed over your kidneys

3.Elevated protein levels in the urine or other signs of a problem with kidney function

4.Worsening kidney function during treatment for high blood pressure

5.Fluid overload and swelling in your body's tissues

6.Treatment-resistant heart failure

Treatment

Treatment for renal artery stenosis may involve lifestyle changes, medication and a procedure to restore blood flow to the kidneys. Sometimes a combination of treatments is the best approach. Depending on your overall health and symptoms, you may not need any specific treatment.

Lifestyle changes

If your blood pressure is moderately or severely elevated, a healthy lifestyle — limiting salt, eating healthy foods and getting regular physical activity — can help control your blood pressure.

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:

1.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

2.Diuretics, also known as water pills, which help your body eliminate excess sodium and water

3.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

4.Calcium channel blockers, which help relax blood vessels

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

Causes

The two main causes of renal artery stenosis include:

1.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.

2.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 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 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 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.

Risk factors

Most cases of renal artery stenosis result from narrowed kidney arteries. Risk factors that make narrowed arteries more likely in your kidneys and other parts of your body include:

1.Aging

2.High blood pressure

3.High cholesterol

4.Diabetes

5.Obesity

6.Smoking and other tobacco use

7.A family history of early heart disease

8.Lack of exercise

Complications

Possible complications of renal artery stenosis include:

1.High blood pressure

2.Kidney failure, requiring treatment with dialysis or a kidney transplant

3.Fluid retention in your legs, causing swollen ankles or feet

4.Shortness of breath due to a sudden buildup of fluid in the lungs

Lifestyle and home remedies

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

1.Maintain a healthy weight. When your weight increases, so does your blood pressure. If you're overweight, losing weight may help to lower your blood pressure.

2.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.

3.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.

4.Reduce stress. Lowering stress levels may decrease your blood pressure.

5.Drink alcohol in moderation, if at all. Too much alcohol may increase your blood pressure.

6.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.

Is renal artery stenosis serious?

Renal artery stenosis is a narrowing of arteries that carry blood to one or both of the kidneys. Most often seen in older people with atherosclerosis (hardening of the arteries), renal artery stenosis can worsen over time and often leads to hypertension (high blood pressure) and kidney damage.

What is the most common cause of renal artery stenosis?

Renal artery stenosis (RAS), or renal artery disease, occurs when the arteries that carry blood to your kidneys get too narrow. Atherosclerosis (plaque buildup in your arteries) is the most common cause. RAS can lead to serious health problems, including high blood pressure, chronic kidney disease or kidney failure.

When does renal artery stenosis require surgery?

You may need surgery if your renal artery stenosis does not improve with more conservative treatments, if it becomes more severe, or if it is caused by fibromuscular dysplasia.

How long does a renal artery stent stay in?

The stent remains in place permanently. During the procedure, a series of X-rays, called fluoroscopy, is used to help the doctor visualize the catheter and stent inside the artery. The procedure lasts 30 to 90 minutes, depending on the severity of the narrowing.