Renal artery stenosis is a narrowing in the blood vessels of the kidneys. This narrowing can reduce the flow of blood to the kidneys. With reduced blood flow, the kidneys do not function properly. Over time, reduced blood flow to the kidneys can lead to high blood pressure and chronic renal disease (the slow loss of kidney function). High blood pressure damages the small blood vessels in the kidneys, reducing their ability to filter waste from the blood. Renal artery stenosis develops and worsens over time. Without treatment, kidney damage will progress and can result in kidney failure.
Causes of renal artery stenosis
Atherosclerosis (hardening of the arteries) causes renal artery stenosis. Atherosclerosis occurs when plaque builds up on the artery walls, narrowing them and slowing blood flow. Factors that increase your risk for atherosclerosis include:
- Smoking
- High blood pressure
- High cholesterol
- Obesity
- Family history of heart or vascular disease
Many of these risk factors can be reduced or eliminated by changing your lifestyle.
Symptoms of renal artery stenosis
Because renal artery stenosis develops slowly and worsens over time, there are no obvious symptoms.
Why choose Ohio State for renal artery stenosis?
Ohio State's vascular surgeons are experts in the treatment of renal artery stenosis. They offer both minimally invasive treatments, such as opening of the renal arteries with stents, and they also perform open bypass surgeries to improve blood flow to the kidneys, if necessary.
How Ohio State diagnoses renal artery stenosis
Tests to diagnose renal artery stenosis include:
- Angiogram – An X-ray of blood vessels to identify blockage; it is performed by inserting a tube into an artery in the leg and injecting a contrast dye into the artery
- CT scan (computed tomography scan, also called CAT scan) – An imaging procedure that uses X-rays and computer technology to produce cross-sectional, detailed images of the body, including bones, muscles, fat and organs
- MRA (magnetic resonance angiography) – A noninvasive imaging procedure that uses large magnets, radiofrequencies and a computer to evaluate blood flow through arteries
- Ultrasound – A noninvasive test that uses ultrasonic sound waves to produce images
How Ohio State treats renal artery stenosis
Treatment focuses on preventing further damage to the blood vessels of the kidneys, which can lead to chronic kidney disease. Lifestyle changes, such as quitting smoking, avoiding fatty foods, following a healthy, low-fat diet and exercising may help patients reduce their risk factors for high blood pressure.
Medications
Your physician may prescribe medications to lower your blood pressure. They may include:
- Diuretics
- Beta blockers
- Angiotensin-converting enzymes (ACE) inhibitors
- Calcium channel blockers
If plaque is blocking the renal artery, your physician may recommend a procedure to open the artery.
Procedures
Angioplasty is a minimally invasive procedure to open blocked arteries and increase blood flow. During this procedure, a surgeon inserts a catheter through small incisions in the groin, guiding it to the renal artery. The catheter carries a tiny balloon, which is inflated and deflated, pushing built-up plaque against the artery wall. A stent may be inserted to prevent the artery from becoming blocked again and to improve blood flow.
Surgery
- Endarterectomy: A surgical procedure that removes the inner lining of an artery narrowed by plaque buildup
- Bypass graft: A procedure that reroutes blood flow around the blocked area of the artery. The graft, which the surgeon connects above and below the blockage, is made either from a portion of one of your veins or made from a synthetic material.