Renal Artery Stenosis

What is Renal Artery Stenosis?

Renal artery stenosis occurs when one or both of the renal arteries that carry blood to the kidneys are narrowed, causing high blood pressure, reduction in kidney function and — in severe cases — kidney failure.

Causes

Most cases of renal artery stenosis are caused by a buildup of plaque on the walls of the renal arteries, causing a hardening of the arteries known as atherosclerosis. The atherosclerosis reduces or stops blood supply to the kidney, damaging the kidney and limiting its ability to remove waste and extra fluid from the blood.

Risk Factors

• Smoking
• Being overweight (a Body Mass Index of 25 or higher)
• Diabetes
• High cholesterol
• Family history of cardiovascular disease
• High blood pressure

What are the Symptoms?

In many cases, symptoms of renal artery stenosis don´t appear until the disease reaches an advanced stage. The most common symptom is high blood pressure, especially if it occurs suddenly, the patient has no family history of high blood pressure or the patient has a hard time controlling it.

How is Renal Artery Stenosis Diagnosed?

• Examination by the doctor: The doctor may listen for a bruit — an unusual sound that occurs when blood flows through a narrowed artery – by placing a stethoscope on the abdomen.
• Computed Tomography Angiography (CTA): A powerful CT scanner takes thin X-ray views of the renal arteries while a dye is injected into the arm vein to determine if there are any areas with poor blood flow or narrow arteries.
• Magnetic Resonance Angiography (MRA): Radio waves and magnetic fields are used to show areas of poor blood flow. A patient will be injected with a contrast material — similar to a dye — to make blood vessels more visible.
• Ultrasound: The ultrasound´s high-frequency sound waves provide the doctor with a picture of the blood flow in the renal arteries and help determine whether there is any narrowing.

Treatment at UVA's Heart and Vascular Center

• Lifestyle changes: UVA's treatment team can work with patients on lifestyle changes — such as quitting smoking, getting more exercise and making diet changes — that will help make the renal arteries healthier.
• Medication: A patient may be prescribed a combination of blood-pressure medications to treat the high blood pressure. A patient also may receive cholesterol-lowering medications to prevent plaque from forming and blood thinners, such as aspirin, to help blood flow through the narrowed arteries.
• Endarterectomy: An endarterectomy is a surgical procedure where plaque causing a narrowing or blockage in the renal artery is removed, opening the artery and improving blood flow.
• Angioplasty and stenting: In this procedure, a doctor inserts a catheter with a balloon on its tip and runs it to the area of the renal artery that is blocked or narrowed. The balloon is inflated, pushing the plaque into the artery´s walls, which opens up the artery. A small metal tube called a stent is then inserted to keep the artery open.
• Bypass grafts: Similar to heart-bypass procedures, veins are taken from elsewhere in the body and used to reroute blood flow around a blockage in the renal artery.