Renal artery stenosis (RAS) is a condition in which the blood vessels that feed oxygen-rich blood to the kidneys become obstructed. It can be caused by atherosclerosis (narrowing of the artery due to the buildup of plaque), fibromuscular disease in which fibrous tissue grows in the arterial wall, or scar tissue caused by injury to the kidney.

Atherosclerosis is the most common cause of renal artery stenosis, especially among the elderly. This is the same atherosclerosis that can block the coronary arteries and eventually result in a heart attack.

Atherosclerosis in the renal arteries is a form of peripheral arterial disease (PAD). Other forms of PAD include cerebrovascular disease, lower extremity PAD and mesenteric arterial disease.

Renal artery stenosis is a common cause of high blood pressure (hypertension) because it can restrict blood flow to the kidneys, which can result in elevated blood pressure. The kidneys serve as filters, and they remove waste products and excess fluids from the body. In this role, they receive almost one-third of the body’s blood flow, and any obstruction in their function has an effect throughout the body.

Renal artery disease may be suspected when an individual exhibits hypertension that is difficult to control. The condition may be discovered during a physical examination when a bruit (whooshing sound) is heard through a stethoscope that is placed over the patient’s kidneys. To diagnose renal artery stenosis, physicians typically order imaging tests that include radionuclide renogram, duplex ultrasound, and/or magnetic resonance angiogram (MRA).

The treatment for renal artery stenosis varies depending on the extent of the obstruction and the severity of the symptoms. Treatment of renal artery stenosis caused by atherosclerosis often involves risk factor modification and may involve catheter-based procedures or bypass surgery. Risk factors for this condition that are not controllable include gender, age, ethnicity and family history. Risk factors that can be modified include smoking, lack of regular exercise, eating a fat diet, obesity, uncontrolled diabetes or hypertension, stress or anger and high LDL cholesterol and low HDL cholesterol.