Narrowed Kidney Arteries: What Renal Artery Stenosis Is, Why It Happens, and How It Is Treated
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 17, 2026
Quick Answer: Renal Artery Stenosis at a Glance
Renal artery stenosis is narrowing of one or both renal arteries, so the kidneys receive too little oxygen-rich blood, injuring kidney tissue and raising blood pressure [1]. It often causes no symptoms and is suspected when high blood pressure starts suddenly or is hard to control [1]. It usually results from atherosclerosis [1] and is treated with lifestyle changes, medicines or stenting [2].
Feature | Details |
What it is | Narrowing of one or both renal arteries, so the kidneys get too little oxygen-rich blood [1]. |
What it causes | Injured kidney tissue and high blood pressure throughout the body, because the kidneys can't filter waste and remove extra fluid properly [1]. |
What it feels like | Often nothing at first. It is usually suspected when high blood pressure starts suddenly, appears before 30 or after 55, or becomes hard to control [1]. |
Why it happens | Most often from fatty plaque buildup in the artery walls (atherosclerosis). Less often from fibromuscular dysplasia, in which the muscle in the artery wall grows abnormally [1]. |
How it's treated | Lifestyle changes, blood pressure medicines, and sometimes procedures that restore blood flow, such as stenting or bypass surgery [2]. |
What the research says
Stenting didn't beat medicine alone in a large trial. The CORAL trial randomly assigned 947 people with atherosclerotic renal artery stenosis and either hard-to-control high blood pressure or chronic kidney disease to medical therapy plus stenting or medical therapy alone. Over a median of 43 months, serious cardiovascular and kidney events occurred in 35.1% of the stenting group and 35.8% of the medicine-only group (hazard ratio 0.94, 95% CI 0.76–1.17). Systolic blood pressure was a modest 2.3 mm Hg lower with stenting (95% CI 0.2–4.4). (Cooper et al., N Engl J Med, 2014) [3]
A pooled analysis reached the same conclusion. A meta-analysis of 7 randomized trials with 2,139 patients found that angioplasty, with or without stenting, was not superior to medical therapy for any outcome. Kidney events occurred in 19.58% of the stenting group and 20.53% of the medical therapy group (odds ratio 0.945, 95% CI 0.755–1.182). The authors suggest future studies look for subgroups that might benefit. (Riaz et al., Am J Cardiol, 2014) [4]
What Is Renal Artery Stenosis?
Your kidneys filter waste products out of your blood and remove extra fluid from your body [1]. To do this work, they need a steady supply of oxygen-rich blood, which two arteries, the renal arteries, carry to them. In renal artery stenosis, one or both of these arteries narrow [1]. "Stenosis" is the medical word for abnormal narrowing.
With less blood reaching the kidneys, two problems can develop at the same time: kidney tissue can become injured, and blood pressure can rise throughout the body [1]. That is why renal artery stenosis matters. It can sit quietly behind high blood pressure that seems to come out of nowhere.
What Are the Symptoms of Renal Artery Stenosis?
Renal artery stenosis often causes no symptoms at all until it is advanced, and in many cases a healthcare professional finds it while testing for something else [1]. The clearest warning signs involve blood pressure that behaves in an unusual way, so paying attention to when and how high blood pressure shows up matters.
Sign | What it looks like |
Sudden or worsening high blood pressure | High blood pressure that begins suddenly or gets worse without a known cause [1] |
Unusual age of onset | High blood pressure that begins before age 30 or after age 55 [1] |
Hard-to-control blood pressure | High blood pressure that is difficult to manage [1] |
Bruit | A whooshing sound as blood flows through a narrowed vessel, heard through a stethoscope placed over the kidneys [1] |
Fluid buildup | Swelling in the body's tissues caused by fluid buildup [1] |
Hard-to-treat heart failure | Heart failure that doesn't respond well to treatment |
What Causes Renal Artery Stenosis?
Renal artery stenosis is most often caused by plaque buildup in the arteries (atherosclerosis) [1], while fibromuscular dysplasia is another cause that is most often found in women aged 40 to 60, though it can occur at any age, including childhood [1].
Cause 1: Plaque Buildup (Atherosclerosis)
Atherosclerosis is a buildup of fats, cholesterol, and other substances, called plaques, on artery walls. As the buildup grows, the plaque can harden, which lowers blood flow and causes kidney scarring [1]. In time, the plaque narrows the artery. Atherosclerosis happens in many areas of the body, not only the kidneys, and it is the most common cause of renal artery stenosis [1].
Cause 2: Fibromuscular Dysplasia
Fibromuscular dysplasia is a condition in which the muscle in the artery wall doesn't grow as it should [1]. It is most often found in women aged 40 to 60, though it can start at any age, including childhood [1]. The affected renal artery has narrow sections alternating with wider sections, which looks like beads on artery images [1]. The artery can narrow so much that the kidney doesn't get enough blood, which can lead to high blood pressure at a young age [1]. It can affect one or both kidneys. Experts don't know what causes it, but it is more common in people assigned female at birth and may be present at birth (congenital) [1].
What Raises Your Risk of Renal Artery Stenosis?
Renal artery stenosis risk factors overlap with those for heart disease and include older age, high blood pressure, high cholesterol, diabetes, obesity, smoking and lack of exercise [1].
Older age
High blood pressure
High cholesterol
Diabetes
Obesity
Smoking and other tobacco use
A family history of early heart disease
Lack of exercise
What Complications Can Renal Artery Stenosis Cause?
Renal artery stenosis can cause high blood pressure, chronic kidney disease or kidney failure, and fluid retention that leads to swollen ankles or feet [1].
High blood pressure: the narrowed kidney arteries push blood pressure up throughout the body [1].
Chronic kidney disease or kidney failure: if high blood pressure isn't managed over time, it can damage the kidneys. Kidney failure needs treatment with dialysis or a kidney transplant [1].
Fluid retention in the legs: excess fluid can cause swollen ankles or feet [1].
How Is Renal Artery Stenosis Diagnosed?
Renal artery stenosis is diagnosed with a physical exam, medical history and blood and urine tests, followed by imaging of the arteries when suspicion is higher. During the exam, the healthcare professional listens with a stethoscope over the kidneys for the whooshing bruit that can mean a kidney artery is narrowed [1] [2]. Blood and urine tests check how the kidneys work [2], and separate tests measure hormones that help control blood pressure [2]. When suspicion is higher, imaging tests look at the arteries directly:
Doppler ultrasound: high-frequency sound waves let the professional see the arteries and kidneys, check how they work, find blockages, and measure how severe a blockage is [2].
CT scan: X-ray techniques make detailed images, and a computer builds cross-sectional "slices" of the renal arteries. A dye injection may show blood flow [2].
Magnetic resonance angiography (MRA): radio waves and strong magnetic fields create detailed images of the renal arteries and kidneys, and a dye outlines the blood vessels during imaging [2].
Renal arteriography: a special X-ray exam that finds the blockage. Dye is fed into the renal arteries through a long, thin tube called a catheter. It is mainly used for people likely to need a stent to widen the artery [2].
How Is Renal Artery Stenosis Treated?
Treatment may involve lifestyle changes, medicine, and a procedure to restore blood flow to the kidneys [2]. One important point first: if your arteries are not blocked, you may not need treatment [2].
Lifestyle Changes
If blood pressure is too high, lifestyle changes can help manage it. These include limiting salt, eating healthy foods, and moving more [2].
Medicines
Medicine can often treat high blood pressure linked to renal artery stenosis. It may take time and patience to find the right medicine or combination [2]. Common choices include:
ACE inhibitors and ARBs (angiotensin II receptor blockers): relax blood vessels and keep them from narrowing; because they can sharply lower kidney function when both kidney arteries are narrowed, kidney function and potassium are checked with blood tests soon after starting [2].
Diuretics ("water pills"): help the body get rid of salt and water [2].
Beta blockers and alpha-beta blockers: make the heart beat more slowly and with less force, or widen the blood vessels [2].
Calcium channel blockers: help relax blood vessels [2].
If atherosclerosis is the cause, your healthcare professional may also suggest aspirin and a cholesterol-lowering medicine [2].
Procedures
Some people may have a procedure to restore blood flow through the renal artery, called renal angioplasty [2]. Procedures are considered for people who don't do well on medicine alone, can't take medicine, often retain fluid, or have heart failure that is hard to treat [2]. Large studies in atherosclerotic disease have not shown that stenting adds benefit over medicines for most people [3] [4], so medicines remain the foundation of treatment.
Renal angioplasty and stenting: the narrowed renal artery is widened and a small tube called a stent is placed inside the vessel to hold the walls open so blood flows better [2]. With fibromuscular dysplasia, the artery may be widened without a stent [2].
Renal artery bypass surgery: a surgeon adds another blood vessel to create a new route for blood to reach the kidneys, sometimes joining the renal artery to a vessel from the liver or spleen [2]. It is mainly done if angioplasty doesn't work [2] or more surgery is needed [2].
What Home Habits Help Manage Renal Artery Stenosis?
Home habits that help manage renal artery stenosis include keeping a healthy weight, using less salt, being physically active and not using tobacco [2].
Get to and stay at a healthy weight: when weight goes up, blood pressure goes up [2], and losing weight may lower it.
Use less salt: salt and salty foods make your body hold on to fluid [2], which may raise blood pressure.
Be physically active: activity may help you lose weight and lower your risk of heart disease, high cholesterol, and high blood pressure. Check with your healthcare professional before starting an exercise program [2].
Don't use tobacco: tobacco harms blood vessel walls and speeds up hardening of the arteries [2]. Ask your healthcare team for help quitting.
How Should I Prepare for My Appointment?
Preparing for a renal artery stenosis appointment means listing your symptoms, medicines, key medical information and questions, and possibly bringing a family member or friend. Consider bringing a family member or friend [2], and make a list of:
Your symptoms: what they are and when they began, including ones that don't seem linked to the reason for your visit [2].
All medicines: every medicine, vitamin, and supplement you take, with doses [2].
Key medical information: including past or current smoking or other tobacco use [2].
Questions to ask: such as what is the most likely cause, what tests do I need, will this go away or last, what treatments are there, and what is a good blood pressure level for me.
Your healthcare professional may ask whether you smoke or use tobacco, whether anything makes your symptoms better or worse, what your blood pressure usually is, whether you have had tests of your kidney function, and whether anyone in your family has high blood pressure or kidney disease [2].
What is the bottom line on renal artery stenosis?
Renal artery stenosis is a quiet condition with a loud consequence: high blood pressure. It happens when the arteries that feed the kidneys narrow, most often from plaque buildup [1], and the kidney tissue doesn't get the blood it needs. Because it rarely causes symptoms until it is advanced, the pattern of your blood pressure, such as sudden onset, onset before 30 or after 55, or blood pressure that is hard to control [1], is often the clue that leads to a diagnosis. The condition is manageable: lifestyle changes and medicines handle many cases, and procedures can restore blood flow when needed [2]. If your blood pressure behaves unusually, getting it checked can protect both your heart and your kidneys.
Take the next step: If you have high blood pressure that started suddenly, began before 30 or after 55, or is hard to control, talk to a healthcare professional. A listen with a stethoscope, blood and urine tests, and imaging can show whether narrowed kidney arteries are to blame.
Frequently Asked Questions
What is renal artery stenosis?
Renal artery stenosis is a narrowing of one or both renal arteries, the blood vessels that carry blood to the kidneys. The narrowing reduces oxygen-rich blood flow, which can injure kidney tissue and raise blood pressure throughout the body [1].
What does renal artery stenosis feel like?
Often it causes no symptoms until it is advanced [1]. Doctors suspect it when high blood pressure begins suddenly, starts before age 30 or after age 55, or is hard to manage [1]. A whooshing sound (bruit) over the kidneys and fluid-related swelling can also occur [1].
What causes renal artery stenosis?
The two main causes are atherosclerosis, in which fatty plaque builds up, hardens, and narrows the artery walls, and fibromuscular dysplasia, in which the muscle in the artery wall grows abnormally and creates bead-like narrow and wide sections [1].
Which is more common, plaque buildup or fibromuscular dysplasia?
Atherosclerosis (plaque buildup) is the most common cause [1]. Fibromuscular dysplasia is less common and is most often found in women aged 40 to 60, though it can occur at any age [1].
Who is most at risk?
Risk factors include older age, high blood pressure, high cholesterol, diabetes, obesity, smoking or other tobacco use, a family history of early heart disease, and lack of exercise [1]. Fibromuscular dysplasia is more common in people assigned female at birth [1].
What complications can it cause?
High blood pressure, chronic kidney disease or kidney failure if high blood pressure goes unmanaged over time, and fluid retention in the legs that causes swollen ankles or feet [1].
How is it diagnosed?
Diagnosis starts with a physical exam (listening for a bruit over the kidneys), a medical history, and blood and urine tests for kidney function and blood pressure hormones [2]. Imaging, such as Doppler ultrasound, CT scan, MRA, or renal arteriography, shows the narrowed arteries directly [2].
Do I always need a stent?
No. If your arteries are not blocked, you may not need treatment [2], and medicines can often control the high blood pressure. Procedures are considered when medicines are not enough, and large studies in atherosclerotic disease found that adding a stent to medicines did not reduce major heart and kidney events for most people [3] [4].
What treatments are available?
Lifestyle changes (less salt, healthy eating, more activity), blood pressure medicines such as ACE inhibitors, ARBs, diuretics, beta blockers, and calcium channel blockers, and procedures such as renal angioplasty with stenting or renal artery bypass surgery when medicines are not enough [2].
Can renal artery stenosis be reversed?
Narrowing from plaque usually cannot be fully reversed, but medicines and healthy habits can slow it and protect the kidneys. Narrowing from fibromuscular dysplasia often responds well to balloon angioplasty.
Related Reading
Doppler Ultrasound: How It Works, Types, Uses and Results explains the painless scan used to check blood flow and find clots or narrowed vessels.
MRA (Magnetic Resonance Angiography): What It Is, Why It's Done, Procedure and Results explains how magnetic resonance angiography makes detailed pictures of your blood vessels without X-ray radiation.
Renal Scan (Kidney Scan): Types, Preparation, Risks and Results explains the nuclear medicine scan used to measure kidney function, blood flow and blockages.
References
Mayo Clinic Staff. Renal artery stenosis: Symptoms and causes. Mayo Clinic. July 12, 2025. https://www.mayoclinic.org/diseases-conditions/renal-artery-stenosis/symptoms-causes/syc-20352777
Mayo Clinic Staff. Renal artery stenosis: Diagnosis and treatment. Mayo Clinic. July 12, 2025. https://www.mayoclinic.org/diseases-conditions/renal-artery-stenosis/diagnosis-treatment/drc-20352782
Cooper CJ, Murphy TP, Cutlip DE, et al. Stenting and medical therapy for atherosclerotic renal-artery stenosis. N Engl J Med. 2014;370(1):13-22. PMID 24245566. https://doi.org/10.1056/NEJMoa1310753
Riaz IB, Husnain M, Riaz H, et al. Meta-analysis of revascularization versus medical therapy for atherosclerotic renal artery stenosis. Am J Cardiol. 2014;114(7):1116-1123. PMID 25145333. https://doi.org/10.1016/j.amjcard.2014.06.033
This article is for general informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional about your individual condition. Never ignore professional medical advice or delay seeking it because of something you read here.
Medical disclaimer
The information provided in this article is for educational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
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