Renal Artery Stenosis
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 may cause 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 (especially if resistant to high blood pressure medications), people with RAS may also suffer from reduced kidney function which may cause the following symptoms:
- Edema (swelling)
- Increase or decrease in urination
- Muscle cramps
- Weight loss
Individuals with RAS may also suffer from symptoms or complications of hypertension which may include headaches, dizziness, heart problems and stroke. High blood pressure caused by renal artery stenosis is commonly referred to as renovascular 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:
- Invasive angiography
- CT angiography (CTA)
- Magnetic resonance angiography (MRA)
RAS may be discovered as an incidental finding when a person is being tested for other conditions, such as heart disease or peripheral vascular disease.
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, invasive treatment with renal artery angioplasty and stenting is a simple, low risk procedure performed in the catheterization laboratory as an outpatient procedure.
Left untreated, RAS may lead to serious conditions such as chronic kidney disease including renal failure requiring dialysis, and all of the potential complications of uncontrolled hypertension including congestive heart failure, loss of eyesight due to retinopathy, and stroke.