Sponsored Ads

Renal artery stenosis, or RAS, is a condition in which there is narrowing of one or both arteries that carry blood to the kidneys. The arteries carrying blood to the kidneys are called the renal arteries. RAS can cause reduction in kidney function and even elevated blood pressure.

In most cases, renal artery stenosis is caused by atherosclerosis, which causes hardening of the kidney arteries. Cholesterol deposits, called plaques, build up on the inner wall of one or both of the renal arteries, which makes the arterial wall hard and narrow. The narrowing of the artery causes reduction or even total blockage of blood supply to the kidney, which eventually results to kidney damage.

Left untreated, RAS can lead to kidney failure causing wastes and excess fluid to build up in the blood. With total kidney failure, a person needs to undergo dialysis or kidney transplantation to stay alive.

Renal Artery Stenosis Risk Factors

Many factors can put a person at risk for developing renal artery stenosis. Some of the common risk factors include

 Older people between the ages of 50 and 70

 Smoking

 Overweight or obesity

 High blood cholesterol levels

 Diabetes

 A family history of cardiovascular disease

 High blood pressure or hypertension—This can be a cause or a result of RAS.

Symptoms of Renal Artery Stenosis

The condition is considered as a silent disease because the condition may be present for many years without symptoms.

The first sign of renal artery stenosis may be hypertension, which stays elevated even after taking blood pressure medication. Renovascular hypertension is the term used for high blood pressure caused by RAS.

Diagnosis of Renal Artery Stenosis

A doctor cannot diagnose RAS based on blood pressure alone because other conditions can also cause blood pressure to become elevated. The doctor may suspect renal artery stenosis if a person suddenly develops high blood pressure and has no family history of high blood pressure, or if the person’s blood pressure is difficult to control.

The doctor may place a stethoscope on the front or side of the person to listen for bruit (BROO-ee)—a whooshing sound heard when blood flows through a narrowed (stenosed) blood vessel. The absence of this sound, however, does not exclude the possibility of RAS and more tests are needed.

For a more accurate diagnosis, getting a picture of the artery through imaging tests may be ordered by the doctor. Imaging tests may include ultrasound, angiogram, computerized tomography (CT) scans, and magnetic resonance angiograms (MRA).

Treatment of Renal Artery Stenosis

Goals of treatment include:

 Preventing RAS from getting worse

 Treating hypertension that results from RAS

 Relieving the blockage of the renal arteries

Lifestyle Changes

Making lifestyle changes is the first step in the treatment of RAS. Lifestyle changes that people with RAS can do include:

 Exercise
 Maintaining a healthy weight
 Choosing healthy foods
 Quit smoking

These lifestyle changes can help keep the blood vessels clean and flexible.

Blood Pressure Medications

Medications to control renovascular hypertension may be prescribed by the doctor. However, each type of blood pressure medicine has its own potential side effects. The choice of anti-hyperstensive drugs can be best determined by the doctor.

The doctor may also prescribe drugs that lower cholesterol to prevent plaques from forming in the arterial wall.

Surgery

Surgery may be recommended to treat advanced RAS, where the blood vessel is almost or completely blocked. Surgical procedure may be used to upen up the flow of blood to the kidney. Different types of surgical procedures for RAS include:

 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 mesh tube, called a stent, to keep plaque flattened and the artery open.

 Endarterectomy. In an endarterectomy, a vascular surgeon cleans out 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.

Reference:

National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC), National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). NIH Publication No. 07–6020, May 2007

Image Credit: NIDDK Image Library

[Top of Page]