The kidneys are a pair of bean-shaped organs that filter and remove wastes from the blood. Stenosis is narrowing that restricts an opening. Renal artery stenosis occurs when a kidney (renal) artery narrows causing blood flow to that kidney to decrease.
Each kidney is capable of regulating the body’s blood pressure to assure that each organ has an adequate supply of oxygenated blood. This happens by activating a cascade of hormones known as the renin-angiotensin system.
Renal artery stenosis triggers the release of these hormones, which then becomes a cause for
hypertension
(high blood pressure). Since hypertension is a leading cause of
strokes
and
heart attacks
, this is a serious condition that requires diagnosis and treatment.
Renal artery stenosis can also eventually lead to loss of renal function, but since one kidney can perform adequately by itself, both kidneys would have to be affected for
kidney failure
to occur. Both renal arteries are involved 30% of the time.
There are several diseases of arteries that can cause them to become narrowed, including:
The following factors increase your chances of developing renal artery stenosis. If you have any of these risk factors, tell your doctor:
- Atherosclerosis elsewhere in your body in men over 50 years old
- Previous stroke or heart attack
- Smoking
- Hypertension
- Diabetes
High blood pressure is called the “silent killer” because it rarely produces symptoms until a stroke or heart attack occurs. The best way to detect it is to have routine blood pressure measurements. Renal artery stenosis is an unusual cause of hypertension, but an important one because it is curable. Most of the patients with the disease have no symptoms. However, it may also cause fluid retention, shortness of breath, headaches, and ankle swelling.
If both of the renal arteries are blocked, kidney failure occurs. Kidney failure can cause lethargy, decreased mental function, twitching, cramps, convulsions, nausea, vomiting, unpleasant tastes in the mouth, and malnutrition. These symptoms are not specific for kidney failure and may be caused by other health conditions, either more or less serious. If you experience any one of them, see your doctor.
Your doctor will ask about your symptoms and medical history, and perform a physical exam. If you have elevated blood pressure a search for its cause can involve many different tests, but unless there is a specific reason to suspect renal artery stenosis, it may not be considered initially.
Tests may include the following:
- Repeat blood pressure measurements
- A battery of blood and urine tests
-
An
electrocardiogram (EKG, ECG)–
a test that records the heart' s activity by measuring electrical currents through the heart muscle
- A 24-hour urine collection
-
Specific tests of your kidneys include:
- X-rays with intravenous contrast
- X-rays with contrast injected directly into the renal arteries
- Ultrasound
examination of the kidneys
- Radioisotope imaging of the kidneys
- CT
or
MRI
scans with or without injected contrast agents
Talk with your doctor about the best treatment plan for you. If there is significant stenosis and you are healthy enough, repair of the artery is considered superior to medical treatment. Treatment options include the following:
Standard treatment for hypertension may be sufficient if blood pressure can be controlled and the kidneys are functioning adequately. There are many drugs that lower blood pressure. You will be given several until adequate control is achieved. ACE inhibitors should not be used if hypertension is caused bybilateral renal artery stenosis. These drugs are especially effective in those with only a single renal artery which is blocked.
A thin tube is threaded into the renal artery from a puncture in your groin. The tube includes a balloon, laser, or other device that will open the stenosed artery.
If the artery is not suitable for angioplasty, a surgeon may decide to repair it through an incision in your abdomen.
There is no way to prevent renal artery stenosis other than to prevent atherosclerosis through regular exercise, a heart healthy diet, no tobacco, and minimal alcohol.
Last reviewed January 2007 by David Juan, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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