An Essential Guide to Renal Artery Stenosis

Around 10% of Americans will develop renal artery stenosis (RAS) in their lifetimes, yet many are unaware of the warning signs until it’s too late.

This condition — which often develops due to unhealthy lifestyle habits — can be life-threatening, so it’s important to understand the causes and how to prevent them.

In this article, we’ll explore the factors that contribute to RAS, the different treatment options, and the steps you can take to minimize your risk of developing this condition.

What is Renal Artery Stenosis?

Renal artery stenosis (RAS) is a medical condition characterized by the narrowing of one or more of the renal arteries.

These arteries play a crucial role in supplying blood to the kidneys, and when they narrow, blood flow to these organs becomes obstructed.

This can cause a series of complex changes in the body, leading to additional health issues like high blood pressure (hypertension) and kidney damage over time. Symptoms of renal artery stenosis

RAS can be difficult to spot because it’s often asymptomatic in its early stages. However, as the condition progresses, the following symptoms may develop:

• High blood pressure
• Decreased kidney function, which manifests as general fatigue, swollen hands and feet, and unexpected urinary changes
• Pulmonary edema (fluid in the lungs), which can cause shortness of breath
• Upper abdominal pain, especially after eating

It’s important to consult your doctor if you develop any of these symptoms to ensure you get treatment early on and avoid further complications.

Common Causes of RAS

Atherosclerosis

Atherosclerosis is a condition that develops when plaque — a substance comprising fats, cholesterol, and calcium — builds up in the arterial walls.

Over time, this plaque can harden and cause the arteries to narrow, impacting blood flow to the kidneys. This can cause issues like high blood pressure and reduced kidney function.

Individuals with unhealthy lifestyle habits — such as those who smoke or follow high-fat diets — are more at risk of developing this condition.

Fibromuscular dysplasia (FMD)

Fibromuscular dysplasia (FMD) is a condition characterized by the abnormal growth and development of cells in the walls of the arteries.

This can cause the arteries to narrow and weaken. In cases where the growth is substantial, FMD can also cause the widening of the arteries.

The exact cause of FMD isn’t fully understood, but genetic and hormonal factors are thought to play a role.

This condition can also cause similar issues to those of atherosclerosis, including hypertension and impaired kidney function.

Other causes

While atherosclerosis and fibromuscular dysplasia are the primary causes of RAS, several other factors may contribute to or aggravate the condition, including:

• Arterial injury: Trauma to the abdomen — such as penetrating injuries, fractures, or dislocations — can lead to arterial damage, which may prompt the development of RAS. Surgical procedures near the renal arteries may also pose a risk.

• Radiation exposure: Radiation therapy — especially in the abdominal area — can damage to the blood vessels, leading to the narrowing of the renal arteries over time.

• External compression: Rarely, a tumor or abnormal growth close to the renal artery can exert pressure on the artery, causing narrowing and reduced blood flow to the kidneys.

• Vasculitis: Inflammation of the renal artery or other blood vessels (vasculitis) can lead to narrowing and blockage. Conditions such as Takayasu arteritis (TAK) or giant cell arteritis (GCA) can also affect the renal arteries among other vessels, although they are rare.

How is RAS Diagnosed?

A healthcare professional should diagnose RAS using a comprehensive analysis. This process may involve:

• A physical exam where the doctor uses a stethoscope to listen for sounds in the kidney areas that could suggest narrowed arteries

• A review of your medical history

• Blood and urine tests to check your kidney function and measure the levels of hormones that control blood pressure

Your doctor may also recommend imaging tests to confirm their diagnosis, which may include:

• Doppler ultrasound: These are high-frequency sound waves that allow your doctor to see the arteries and kidneys to check their function. This procedure can also help them identify any arterial blockages.

• Computed tomography (CT) scan: A CT scan creates a detailed cross-sectional image of the renal arteries to help your doctor identify any blockages or areas where blood flow is decreased.

• Magnetic resonance angiography (MRA): MRAs create 3D images of the renal arteries and kidney to outline blood vessels. This can help your doctor identify narrowed arteries and determine the severity of blockages.

Depending on the outcome of these tests, your doctor will diagnose your condition and recommend the best treatment options.

Who is at Risk of Developing RAS?

Although anyone can develop RAS, certain groups of people are more at risk. This includes people who:

• Have high cholesterol levels
• Have high blood pressure
• Smoke
• Suffer from insulin resistance
• Have diabetes
• Have peripheral artery disease (PAD)
• Are overweight or obese
• Lack physical activity
• Follow a diet high in fat, cholesterol, sodium, and sugar
• Have a family history of early heart or kidney disease

RAS is also more common in men older than 45 and women over 55, but your risk starts to increase from age 25.

If you fall into any of these categories, speak to your doctor about your individual risk factors for RAS and how you can reduce them.

What are the Treatments for RAS?

Medication

Medication is one of the primary treatment options for RAS, particularly when it comes to managing high blood pressure and reducing cholesterol.

Commonly prescribed medications may include:

• Antihypertensive drugs: These include ACE inhibitors, angiotensin II receptor blockers (ARBs), and calcium channel blockers, which work to lower blood pressure. It's important to note that ACE inhibitors and ARBs should be used cautiously, as they may worsen kidney function.

• Statins: These drugs help lower cholesterol levels, reducing plaque buildup in the arteries and potentially slowing the progression of RAS.

• Antiplatelet agents: Aspirin and similar medications may be prescribed to lower the risk of blood clots from narrowed arteries.

When your doctor recommends medication, always use it exactly as prescribed.

This can help you avoid unpleasant side effects and further complications while managing your condition.

Lifestyle changes

Making suitable lifestyle changes is essential for managing RAS and slowing disease progression. Your doctor may recommend the following adjustments:

• Adopting a heart-healthy diet low in saturated fats, cholesterol and sodium
• Getting more regular exercise
• Quitting smoking
• Maintaining a healthy weight

These changes can reduce further arterial damage and plaque buildup, which can help you avoid additional health complications.

Implementing these lifestyle adjustments also go a long way to improving your overall health and reducing your risk of disease.

Interventional procedures

For cases where medication and lifestyle changes are ineffective or if RAS is severe, interventional procedures may be recommended. These can include:

• Angioplasty with stenting: This is the most common procedure for treating RAS and it involves inserting a catheter and guiding it to the narrowed area of the renal artery. A balloon is then inflated to widen the artery, and a stent is often placed to keep it open.

• Renal artery angioplasty without stenting: In some cases — especially with fibromuscular dysplasia — angioplasty without stenting may be effective in improving blood flow to the kidneys.

Surgical options

Surgery for RAS is less common but may be considered in complex cases or if interventional procedures fail. These surgical procedures may include:

• Bypass surgery
• Endarterectomy
• Renal artery replacement

Your doctor will likely only recommend surgery as a last resort. They will also inform you about the recovery process and how you can take care of your health post-surgery.

Will RAS Resolve Without Treatment?

RAS is a condition that doesn’t typically resolve without treatment and it can worsen if it’s not managed properly.

This means that arteries may continue to narrow, potentially leading to a complete blockage of blood supply to the kidneys.

In severe cases, worsening RAS can cause uncontrolled high blood pressure, chronic kidney diseases, and even kidney failure – which can be fatal.

These complications may be fatal, so it’s important to seek proper treatment for RAS to avoid them.

When Should You See a Doctor About RAS?

It’s essential to consult your doctor as soon as you start experiencing symptoms of RAS. Remember that these symptoms may include:

• High blood pressure
• Impaired kidney or renal function
• Pulmonary edema
• Abdominal or flank pain
• Swollen hands and feet

If you’ve developed RAS, it requires immediate treatment to prevent long-term complications.

If you're in a high-risk group for RAS, like having a family history of heart disease or being a smoker, consult your doctor.

Your doctor can assess your risk and recommend various strategies to help you reduce the likelihood of developing RAS.

Where Can You Learn More About RAS and Other Similar Conditions?

While LifeMD offers care to patients with chronic conditions, RAS is a serious condition that requires ongoing specialty care and extensive work from an in-person healthcare provider.

This being said, if you’re concerned about your kidney health, LifeMD may be able to help.

LifeMD can offer guidance on ways to maintain healthy habits that may support the management of your condition and avoid further complications.

Additionally, a licensed medical provider may be able to treat other conditions contributing to RAS – such as high blood pressure.

Your healthcare provider may offer guidance on effective ways to lower your blood pressure and/or prescribe the appropriate medication.

Make an appointment today to get started.