Renal artery stenosis (RAS) is the narrowing of one or both of the renal arteries, the blood vessels that carry blood to the kidneys from the aorta. RAS often causes high blood pressure and reduced kidney function, however, many times there are no symptoms present until the condition becomes severe. Most cases of RAS are caused by a condition called atherosclerosis, the clogging, narrowing, and hardening of the renal arteries. RAS develops when plaque builds up on the inner wall of the renal arteries and causes the arteries to harden and narrow. RAS may also be caused by fibromuscular dysplasia, an abnormal growth of tissue within the wall of the artery, which causes the blood vessels to narrow.
Symptoms of RAS
In addition to hypertension (high blood pressure), people with RAS may also suffer from reduced kidney function which may cause the following symptoms:
- Edema (swelling) of the hands or feet
- Increase or decrease in urination
- Muscle cramps
- Weight loss
- Darkened skin
Individuals with RAS may also suffer from symptoms of hypertension which may include headaches, dizziness, and fatigue. High blood pressure caused by renal artery stenosis is commonly referred to as renal vascular hypertension.
Diagnosis of RAS
RAS may be diagnosed through a physical examination and a review of symptoms. Blood and urine tests may be performed to check cholesterol and creatinine levels and evaluate kidney function.
Additional diagnostic tests may include:
- Catheter angiogram
- MRI scan
- CT scan
- Magnetic resonance arteriogram (MRA)
RAS may be discovered when a person is being tested for other conditions, such as heart problems. RAS may be detected during a coronary angiogram, which is a test that is used to view blood flow through the heart.
Treatment of RAS
RAS may initially be treated with conservative methods to improve blood pressure and relieve the narrowing in the renal arteries. These methods may include lifestyle changes such as stopping smoking, eating a healthy diet and exercise. Medication to control blood pressure and cholesterol-lowering medication to prevent plaque from building up in the arteries, may also be prescribed. If conservative methods are not effective, surgical treatment may include:
- Renal artery bypass
- Renal angioplasty and stenting
- Renal endarterectomy
Left untreated, RAS may lead to serious conditions including chronic kidney disease, coronary artery disease, peripheral vascular disease and stroke.