Renal Artery Stenosis
What is Renal Artery Stenosis?
Renal artery stenosis (RAS) is the narrowing of one or both arteries that carry blood to the two kidneys. RAS can cause high blood pressure and reduce kidney function. RAS is often overlooked as a cause of high blood pressure.
Are you at risk?
You are at greater risk of developing RAS if you smoke or are overweight. RAS is most common in men between the ages of 50 and 70, but women and younger adults can also have it. High cholesterol, diabetes, and a family history of cardiovascular disease are also risk factors for RAS. High blood pressure is both a cause and result of RAS.
What are the symptoms?
RAS can be silent, meaning you will not feel any symptoms, until it becomes severe.
The first sign of RAS may be high blood pressure that stays high even when you take blood pressure medicine. High blood pressure caused by RAS is called renovascular hypertension. Your doctor cannot diagnose RAS based on blood pressure alone because many conditions can cause your blood pressure to rise. If you develop high blood pressure suddenly and have no family history of high blood pressure, or if your blood pressure is difficult to control, your doctor might suspect RAS.
How can RAS be diagnosed?
When blood flows through a narrow vessel, it makes a whooshing sound, called a bruit. Your doctor may place a stethoscope on the front or the side of your abdomen to listen for this sound. The absence of this sound, however, by no means excludes the possibility of RAS.
For a more accurate diagnosis, your doctor may order an ultrasound, CT scan, MRI or an angiogram to get a picture of the artery. The advantage of angiograms is that they give a better picture and therefore more accurate diagnosis of RAS than the other tests. The disadvantage is that angiograms are more invasive than ultrasound imaging. To find out more about angiograms and ultrasound imaging, please follow the links above.
How can RAS be treated?
If RAS advances until the artery is nearly or completely blocked, you may need surgery to open up the flow of blood to the kidney. Different types of surgery for RAS include the following:
- Angioplasty and stenting - Angioplasty is a procedure in which a catheter is put into the renal artery, usually through the groin, just as in a conventional angiogram. In addition, for angioplasty, a tiny balloon at the end of the catheter can be inflated to flatten the plaque against the wall of the artery. Then your doctor may position a small metal tube, called a stent, to keep plaque flattened and the artery open.
- Endarterectomy - In an endarterectomy, the vascular surgeon opens the renal artery and removes the plaque, leaving the inside lining of the artery smooth and clear.
- Bypass surgery - To create a bypass, a vascular surgeon uses a vein or synthetic tube to connect the kidney to the aorta. This new path serves as an alternate route for blood to flow around the blocked artery into the kidney.