Renal Artery Stenosis
What is renal artery stenosis?
Renal artery stenosis (RAS), or renal artery disease, is a narrowing of the arteries that carry blood from your heart to your kidneys. You have two renal arteries that supply blood to your right and left kidneys. One or both of these arteries can develop stenosis. Renal artery stenosis can lead to hypertension (high blood pressure), chronic kidney disease or kidney failure.
Who gets renal artery stenosis?
People with atherosclerosis are at the highest risk for renal artery stenosis. Atherosclerosis develops when plaque (a sticky substance mostly made of fat and cholesterol) builds up on artery walls. Risk factors for RAS include:
- Family history of cardiovascular disease.
- High blood pressure.
- High cholesterol.
- Older age (men and people assigned male at birth/AMAB over 45 and women and people assigned female at birth/AFAB over 55).
- Poor diet (high in sodium, fat and sugar).
What’s the link between renal artery stenosis and peripheral artery disease?
RAS affects the renal arteries that carry blood to your kidneys. Peripheral artery disease (PAD) affects the arteries that carry blood from your heart to your arms and legs. Atherosclerosis is usually the cause of both. Studies show that between 14% to 35% of people with PAD also have RAS.
Research also suggests that chronic kidney disease, which can result from RAS, may put people at a higher risk for PAD. People with both chronic kidney disease and PAD are at an increased risk of heart attack, stroke, limb loss and other serious health complications.
Symptoms and Causes
What are the symptoms of renal artery stenosis?
In many cases, RAS doesn’t cause symptoms. It tends to cause problems, such as high blood pressure and reduced kidney function, only after the disease has progressed. Symptoms of poor kidney function may include:
- Concentration problems or confusion.
- Difficulty sleeping.
- Edema (swelling due to fluid buildup).
- Loss of appetite.
- Muscle cramps.
- Nausea and vomiting.
- Shortness of breath (dyspnea).
- Skin changes, such as dry, itchy or darkened skin.
- Unexplained weight loss.
- Urinating more or less often.
What causes renal artery stenosis?
Between 60% and 90% of RAS cases result from atherosclerosis. Fibromuscular dysplasia usually causes the remaining cases. Fibromuscular dysplasia occurs when there’s abnormal cell growth on artery walls, causing the arteries to narrow. It’s much more common in women and people AFAB — and it may result from genetics or hormones.
What are the complications of renal artery stenosis?
Potential complications of RAS include:
- Chronic kidney disease.
- Coronary artery disease.
- Kidney atrophy (reduced kidney size).
- Kidney failure.
- Peripheral artery disease.
- Renal hypertension (high blood pressure in your renal arteries).
Diagnosis and Tests
How is renal artery stenosis diagnosed?
Sometimes, healthcare providers detect and diagnose renal artery stenosis incidentally. This means it happens during the process of diagnosing or treating another disease. If your healthcare provider suspects RAS, they may perform a variety of tests:
- Physical exam: Your provider checks your blood pressure, looks for swelling in your limbs and listens to your breathing. They may put a stethoscope near your kidneys to listen as blood flows through your arteries. Blood flowing through narrowed arteries often makes a whooshing sound. Unexplained high blood pressure is one of the most common indicators of RAS.
- Kidney function tests: Blood and urine tests, called kidney function tests, can tell how well your kidneys are working. Increased levels of protein, creatinine, nitrogen and other waste products in your body fluids indicate that your kidneys aren’t filtering waste from your blood efficiently.
- Imaging scans: There are a variety of imaging scans that can evaluate the size of your kidneys and how well blood is getting to your kidneys. Your provider may perform a renal scan, duplex ultrasound, computerized tomographic angiography (CTA) or magnetic resonance angiogram (MRA).
Management and Treatment
How is renal artery stenosis treated?
The most common treatments for RAS are lifestyle changes and medication. Surgery may be an option if someone develops severe stenosis in their renal arteries, is at risk of arterial occlusion (blockage), has unmanaged high blood pressure resistant to medications or has progressive loss of kidney function.
How can lifestyle changes help me manage renal artery stenosis?
Your healthcare provider will likely recommend a variety of lifestyle changes to help manage RAS and lower high blood pressure, including:
- Eating a healthy diet low in fat, cholesterol, sodium and sugar.
- Getting regular exercise.
- Losing weight.
- Quitting smoking.
How can medication help me manage renal artery stenosis?
Medication, combined with lifestyle changes, can help regulate high blood pressure and slow or prevent the progression of kidney disease. Your healthcare provider may recommend a combination of drugs:
- Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) block certain hormones that may cause your blood vessels to narrow.
- Aspirin thins your blood so it flows more easily through arteries.
- Beta-blockers and calcium channel blockers reduce high blood pressure.
- Diuretics, or “water pills,” help your kidneys remove extra water from your blood.
- Statins reduce high cholesterol.
What surgeries are available for renal artery stenosis?
Severe RAS not managed by medication may require surgery. The two main types of vascular surgeries for RAS include:
- Angioplasty and stenting: A surgeon inserts a catheter (thin, flexible tube) into your narrowed renal artery. They inflate a tiny balloon inside of your artery to widen it. Next, they place a stent (small mesh tube) in your artery to keep it open and help blood continue flowing to your kidney. Angioplasty and renal artery stenting is a minimally invasive procedure and is the most common type of surgery for RAS.
- Renal artery bypass: A surgeon reroutes blood flow to your kidney by bypassing the narrowed or blocked renal artery. They use a blood vessel graft (usually from your leg) or an artificial tube. The graft or tube is sewn to an existing healthy artery and then attached to the blocked artery (at a place between the blockage and the kidney).
- Renal endarterectomy: A surgeon opens your narrowed renal artery and removes plaque and other substances that may be blocking blood flow.
How can I prevent renal artery stenosis?
You can reduce your risk of RAS by:
- Eating a balanced diet.
- Exercising regularly.
- Managing your blood pressure.
- Maintaining a healthy body weight.
- Not smoking.
Outlook / Prognosis
What’s the outlook for someone with renal artery stenosis?
Renal artery disease (RAS) is a progressive condition, worsening over time. The outlook for someone with RAS depends largely on the severity of the disease. Research shows that the four-year survival rate for people with renal artery blockage of 95% or more is only 48%. So, only about half of people with near-total artery occlusion survive for four years after diagnosis.
When should I contact my healthcare provider about renal artery disease?
Contact a healthcare provider right away if you experience:
- A metallic taste in your mouth.
- Abdominal pain.
- Confusion or problems concentrating.
- Low urine output.
- Nausea and vomiting.
- Swelling in your legs, arms or face.
A note from Cleveland Clinic
Renal artery stenosis (RAS), or renal artery disease, occurs when the arteries that carry blood to your kidneys get too narrow. Atherosclerosis (plaque buildup in your arteries) is the most common cause. RAS can lead to serious health problems, including high blood pressure, chronic kidney disease or kidney failure. Lifestyle changes and medication are the most common treatments for RAS. In some cases, surgery is necessary.
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