What is Renal Artery Stenosis (RAS)?


Severe stenosis of the renal artery

RAS is a condition in which the artery that supplies blood flow to the kidney becomes blocked.


What causes RAS?


Atherosclerosis is the primary cause of RAS(60-70%). Also known as plaque, this is a buildup of cholesterol in the artery. Atherosclerosis is most common in people over the age of 50, and there is a higher incidence in African Americans.

Fibromuscular Dysplasia (FMD) is another cause that accounts for 30-40% of RAS cases. This is a disease in the muscular lining of the artery that causes narrowing of the renal artery. This occurs mostly in younger women. The cause of FMD is unknown. FMD is successfully treated with Renal Artery Angioplasty.


What are the symptoms of RAS?

  • High blood pressure that does not respond to blood pressure medication
  • Deterioration of kidney function because the kidney is unable to excrete toxins from the body.

What can happen if RAS is not treated?


If the kidney is starved of blood flow, it will be unable to filter waste and toxins from the body. Decrease in blood flow can cause permanent kidney damage that may lead to kidney failure. When the kidney(s) sense a reduction in blood flow, a hormone called renin is secreted that further raises blood pressure. This results in a condition known as renovascular hypertension. The following tests can be used to diagnose renal artery stenosis:

  • CTA—Computed Tomography Angiography
  • MRA—Magnetic Resonance Angiography
  • Angiography

What should I expect before my angiogram?

  • Do not eat or drink for 8 hours prior to your procedure.
  • Unless you are on a fluid restriction drink plenty of fluids, especially water, the day before your procedure.
  • If you are diabetic, your insulin or medication will be adjusted.
  • You may be given a medication called Mucomyst to help protect your kidneys from the dye.
  • When you arrive at the hospital, blood work will be drawn to check your blood counts and kidney function.
  • You will meet the interventional radiologist who will be performing your procedure.

What happens during my angiogram?


You will be placed on an X-ray table and an iodine solution will be applied to your groin area to remove bacteria from the skin. You will be given medication through your vein to make you sleepy. You will be awake but comfortable during the procedure.

You will receive a local anesthetic that will numb the skin at the top of your leg, which may feel like a bee sting. Then a thin catheter will be inserted through the skin into a small opening in your artery in order to see the blood flow to your kidneys. An X-ray dye will be injected to visualize the artery better and determine if a blockage is present. The blood flow to the right and left kidney will be examined during the angiogram.

The angiogram will last approximately 45 minutes.


What is Renal Angioplasty?


If a blockage is found, the interventional radiologist will perform the angioplasty. Interventional radiologists are doctors who have special training to diagnose and treat conditions using tiny, miniaturized tools while watching their progress on X-ray or other imaging equipment.

Another thin catheter will be inserted into the renal artery. This catheter has a balloon on the tip of the catheter. The balloon is inflated and deflated several times causing the plaque to be compressed along the wall of the artery. This opens the artery and restores blood flow to the kidney.

A small metal coil, called a stent, may be placed in the artery to hold the artery open, thus preventing a blockage in the future.

This part of the procedure will last about 30- 45 minutes.


What should I expect after the procedure?


A plug made of collagen is placed into the catheter insertion site to seal the artery. You will not require any sutures. Your body will absorb this over the next few weeks.

After the angiogram you will have to lie flat for a few hours and then you will be discharged. If angioplasty is indicated, you will be kept overnight in the hospital, and then you will be discharged home the following morning.

You should notify your doctor if you experience:

  • A lump bigger than the size of a walnut in your groin area
  • A fever
  • Extreme pain or discomfort in the groin area
  • Redness or drainage at the groin site
  • If your groin begins to bleed, apply pressure to the area and call 911.

For more information about this procedure or general information about our interventional radiology practice, please contact one of our clinical coordinators at 513-527-9999.