Renal Artery Stenting
What is renal artery stenting?
Renal artery stenting is a procedure to open the renal arteries – the large blood vessels that carry blood to the kidneys – when they have become blocked due to renal artery stenosis (narrowing of the renal artery). This is most often caused by atherosclerosis or fibrous disease of the arteries. When a renal artery is clogged, blood flow to the kidneys is affected. Stenting opens the blockage and restores normal blood flow.
The kidneys help to control the amount of salt and fluid in the body by filtering blood and making urine. When the blood cannot get to the kidneys to remove salt and water, fluid builds up in the body. In addition, the kidney releases a hormone called renin that promotes the retention of salt and water and also causes the blood vessels in the body to become more rigid. Together, this results in a type of high blood pressure called renovascular hypertension. High blood pressure puts extra strain on the heart and other organs. Renovascular hypertension can also cause kidney failure, which can lead to dialysis or a kidney transplant.
How will I know if I need renal artery stenting?
Your doctor will use certain tests to see if you need renal artery stenting. Among these tests are the following:
- Angiography: During this test, a catheter is inserted through the groin into the aorta, the main artery in the body. The catheter is advanced to the renal arteries and a dye is released. A series of X-rays is taken to see how well the blood is flowing through the arteries.
- Magnetic resonance angiography: This test is similar to regular magnetic resonance imaging, which uses a large magnet to create images of the inside of the body. In magnetic resonance angiography, a contrast dye is injected into the blood so that the area that is being imaged stands out.
- Computed tomography angiography: Computed tomography uses a series of cross-sectional X-rays to build a three-dimensional image of the inside of the body. Again, this test makes use of a contrast dye to highlight the renal arteries.
- Duplex Doppler ultrasonography: This test uses sound waves to measure the size of the narrowed area and the speed of the blood flow within the renal arteries.
Will renal artery stenting cure renal artery stenosis?
In most cases, the angioplasty and stenting procedure does not cure renal artery stenosis, but it can slow the progress. Many patients with renovascular hypertension continue to take blood pressure medicine.
How is renal artery stenting done?
Renal artery stenting is done during a procedure called angioplasty, which involves inserting a small catheter in the diseased renal artery. An angioplasty catheter has a balloon on its end in order to inflate or dilate the narrowed area. Angioplasty is a minimally invasive procedure, which means that it is performed through small incisions rather than by cutting the body open.
Angioplasty takes place in a catheterization laboratory, a room equipped with special X-ray and imaging machines. Before the procedure, you will receive medication to help you relax, but you will be awake. You are also given a contrast dye that makes your arteries easier to see on the imaging equipment. You may feel some discomfort during the procedure, but it is generally not painful.
During the angioplasty:
- A catheter, a flexible hollow tube, is inserted through a tiny incision, or opening, in your groin.
- Using the imaging equipment, the doctor carefully guides the catheter to the narrow part of your renal artery.
- The doctor then places a guide wire with a balloon on its tip through the catheter to the spot in the artery and inflates the balloon to open the blockage.
- The stent, a fine mesh tube, is then pressed into the artery wall. The stent is left in the artery to keep it open to maintain blood flow.
Risks / Benefits
What are the risk factors for restenosis?
Restenosis is more likely to occur in people whose arteries were very narrow, people over age 65, women, and smokers. In some cases, another stenting procedure may be needed to unblock the artery again.
What are the risks of renal artery stenting?
The risks of renal artery stenting include:
- Bruising where the catheter was inserted.
- Bleeding in or around the insertion site.
- Damage to the artery.
- Blood clots.
- Allergic reaction to the dye used during the procedure.
- Stent misplacement.
- Kidney failure.
Recovery and Outlook
What will happen after the stenting procedure?
You may need to take a blood-thinning medicine to help your blood flow properly until the area around the stent heals, and to prevent blood clots. Sometimes, new blockages can develop in a different area of the renal artery. In addition, an artery can narrow again– a condition called restenosis – so it is important that you see your doctor for all follow-up appointments.
When to Call the Doctor
When should I call my doctor?
Call your doctor if any of the following occur:
- You have a fever.
- You have problems breathing.
- You develop a rash.
- The area where the catheter was inserted becomes red, swollen, and
painful, or it oozes blood.
- The leg in which the catheter was inserted becomes painful, cold, pale, or weak.
- You notice new pains in the abdomen or the flank on the side of the treated kidney.
- You become lightheaded and have a very low blood pressure.
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