Renal Artery Stenosis: Symptoms, Causes, Diagnosis, And Treatment

What Is Renal Artery Stenosis?

Renal artery stenosis is the narrowing of one or both arteries that carry oxygen-rich blood from the heart to the kidneys. When these vital blood vessels become constricted, your kidneys receive an insufficient blood supply, triggering a cascade of health problems.

The restricted blood flow to the kidneys forces these organs to work harder to filter waste from your blood. In response, your kidneys release hormones that raise blood pressure, often leading to resistant hypertension that is difficult to control with standard medications.

Over time, kidney ischemia, a condition where kidney tissue doesn't receive adequate oxygen, can develop. This oxygen shortage can cause permanent kidney damage, scarring, and potentially kidney failure if left untreated.

Types of Renal Artery Stenosis

• Atherosclerotic renal artery stenosis: The most common form, typically affecting older adults.
• Fibromuscular dysplasia (FMD): Less common but often affects younger people, particularly women.
• Secondary stenosis: Caused by other conditions like vasculitis or arterial dissection.

Atherosclerotic Renal Artery Stenosis

Atherosclerotic renal artery stenosis occurs when fatty deposits, cholesterol, and calcium build up inside the renal arteries, forming plaques. The plaques gradually reduce blood flow to your kidneys, causing them to shrink and function poorly. As kidney ischemia worsens, your body's blood pressure regulation becomes increasingly disrupted, creating a dangerous cycle of rising pressure and further arterial damage.

Fibromuscular Dysplasia (FMD)

Fibromuscular dysplasia represents a different category of renal artery stenosis types, characterised by abnormal cell growth within the arterial walls. This condition creates a distinctive "string-of-beads" appearance on imaging studies, where the artery shows alternating areas of narrowing and widening. The exact the causes of fibromuscular dysplasia remain unclear, though researchers suspect genetic factors, hormonal influences, and mechanical stress may contribute.

What Causes Renal Artery Stenosis?

• Atherosclerosis: Plaque buildup from high cholesterol, diabetes, and smoking
• Fibromuscular dysplasia: Abnormal arterial wall development, often genetic
• Inflammatory conditions: Vasculitis and other autoimmune disorders
• Arterial dissection: Tears in the artery wall from trauma or high blood pressure
• External compression: Tumours or enlarged lymph nodes pressing on arteries
• Congenital abnormalities: Birth defects affecting renal artery structure

Risk Factors

For atherosclerotic stenosis:
• Age over 55 years
• High blood pressure
• High cholesterol levels
• Diabetes mellitus
• Smoking history
• Family history of cardiovascular disease
• Existing heart or peripheral artery disease

For fibromuscular dysplasia:
• Female gender
• Age under 50 years
• Family history of FMD
• Unexplained early-onset high blood pressure

Symptoms of Renal Artery Stenosis

• Severe, sudden-onset high blood pressure that's difficult to control with medications.
• Previously well-controlled blood pressure that suddenly worsens without clear explanation.
• Declining kidney function detected through blood tests.
• Sudden deterioration in kidney function after starting ACE inhibitors or ARBs.
• Fluid retention causing swelling in legs, ankles, or around the eyes.
• Unexplained shortness of breath or episodes of sudden lung fluid buildup.
• Persistent fatigue, dizziness, or difficulty concentrating.
• Increased protein levels in urine.

When Symptoms Become Serious

• Severely elevated blood pressure with headache, vision changes, or chest pain.
• Repeated episodes of acute shortness of breath or sudden lung congestion.
• Rapid decline in kidney function, especially after starting blood pressure medications.
• New or worsening fluid retention with sudden weight gain.
• Signs of a hypertensive emergency include confusion, severe headache, vision changes, or stroke-like symptoms.

Renal Artery Stenosis Complications

• Resistant hypertension that's extremely difficult to control
• Chronic kidney disease with progressive function decline
• End-stage kidney disease requiring dialysis or transplant
• Recurrent episodes of sudden heart failure
• Increased risk of heart attack and stroke
• Permanent kidney scarring and shrinkage

When to Seek Medical Help

• High blood pressure developing before age 30 or after age 55 without a family history.
• Previously controlled blood pressure has become difficult to manage.
• Sudden decline in kidney function shown by blood tests.
• Unexplained fluid retention or swelling.
• Repeated chest tightness or breathing difficulties.
• Known cardiovascular disease with worsening blood pressure or kidney function.

How Renal Artery Stenosis Is Diagnosed

1. Comprehensive medical history and physical examination: The doctor reviews blood pressure patterns and cardiovascular risk factors, and performs a physical assessment.
2. Laboratory blood and urine tests: Evaluation of kidney function, electrolyte levels, and urine protein.
3. Initial imaging studies: Non-invasive tests like Doppler ultrasound, CT angiography, or MR angiography.
4. Functional assessment: Additional tests measuring how blood flow affects kidney function.
5. Confirmatory angiography: The gold-standard catheter-based imaging technique that can both diagnose and treat renal artery stenosis.
6. Comprehensive evaluation: Assessment of overall cardiovascular health and treatment planning.

Imaging Tests Used

• Renal artery Doppler ultrasound: A non-invasive, first-line screening test
• CT angiography (CTA): Produces detailed 3D images using contrast dye
• MR angiography (MRA): Magnetic resonance imaging of renal arteries
• Conventional angiography: Gold standard providing the most detailed images
• Nuclear medicine scans: Assess individual kidney function

Blood & Urine Tests

• GFR With Creatinine Test: Measures kidney function
• Blood Urea Nitrogen Test (BUN Test): Indicates waste product buildup
• Electrolytes Test: Checks sodium, potassium, and other minerals
• Urine Routine Test (Urine R/M Test): Detects protein, blood, or other abnormalities
• PRA Plasma Renin Activity: Measures hormone levels related to blood pressure regulation.

Treatment Options for Renal Artery Stenosis

Effective renal artery stenosis treatment depends on the underlying cause, severity, and individual patient factors. Treatment goals include controlling blood pressure, preserving kidney function, and preventing cardiovascular complications. The approach typically combines medications, lifestyle modifications, and sometimes interventional procedures.

Medications to Control Blood Pressure

• ACE inhibitors or ARBs: First-line treatments, but require careful monitoring
• Calcium channel blockers: Effective for blood pressure control
• Diuretics: Help manage fluid retention
• Beta-blockers: Reduce heart rate and blood pressure
• Statins: Lower cholesterol and stabilize arterial plaques

Interventional Procedures

• Renal artery angioplasty: Balloon inflation to widen narrowed arteries
• Stent placement: Metal mesh tubes to keep arteries open
• Drug-eluting stents: Metal mesh tubes coated with medication to prevent re-narrowing
• Cutting balloon angioplasty: Specialised balloons for complex lesions

Angioplasty With or Without Stenting

Renal artery angioplasty involves threading a small balloon catheter through the blood vessels to the narrowed renal artery. The balloon inflates to compress plaque against the artery wall, restoring normal blood flow and relieving kidney ischemia.

Stenting often accompanies angioplasty, particularly for atherosclerotic stenosis. The metal mesh stent provides structural support, helping prevent the artery from narrowing again. For fibromuscular dysplasia, angioplasty without stenting frequently achieves excellent results.

Surgical Treatment for Renal Artery Stenosis

Surgical intervention becomes necessary when less invasive treatments fail or aren't suitable. Surgical options include bypass procedures using grafts from other blood vessels or direct arterial reconstruction.

While surgery offers excellent long-term results, it carries higher risks than angioplasty. Surgeons typically reserve these procedures for younger patients with good overall health who have failed other treatments or have complex arterial anatomy unsuitable for angioplasty.

Long-Term Management & Monitoring

Successful renal artery stenosis treatment requires ongoing monitoring and lifestyle modifications. Regular follow-up appointments allow healthcare providers to assess treatment effectiveness and adjust medications as needed.

Patients should monitor their blood pressure at home, maintain a heart-healthy diet low in sodium, engage in regular exercise as tolerated, and avoid smoking. Routine blood tests help track kidney function, while periodic imaging studies may be necessary to ensure arteries remain open.

Can Renal Artery Stenosis Be Prevented?

• Maintain healthy blood pressure through diet, exercise, and medication compliance.
• Limit intake of protein, cholesterol, sodium, and potassium to help slow kidney function decline, as recommended by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
• Manage diabetes effectively through blood sugar monitoring and treatment.
• Avoid tobacco products completely, as smoking accelerates arterial disease.
• Exercise regularly to improve cardiovascular health and blood flow.
• Eat a balanced diet rich in fruits, vegetables, and whole grains while limiting processed foods.

Living With Renal Artery Stenosis

Managing renal artery stenosis successfully requires commitment to long-term care and lifestyle modifications. Many patients lead normal, active lives with proper treatment and monitoring.

Work closely with your healthcare team to optimise your treatment plan. Take medications as prescribed, attend regular follow-up appointments, and promptly report any new or worsening symptoms. Consider joining support groups to connect with others facing similar challenges and share experiences about managing this condition.

Conclusion

Renal artery stenosis is a serious condition that requires prompt recognition and appropriate treatment. Understanding renal artery stenosis symptoms helps ensure early detection, while knowing its various causes empowers you to make informed lifestyle choices.

Modern renal artery stenosis treatment options offer excellent outcomes when implemented properly. Whether through medications, interventional procedures, or surgical intervention, effective management can control blood pressure, preserve kidney function, and prevent serious complications.

At Metropolis Healthcare, we understand the importance of accurate diagnostic testing in managing conditions like renal artery stenosis. With our comprehensive portfolio of more than 4,000 tests and profiles, we provide the precise diagnostics your healthcare provider needs to guide effective treatment decisions. Our extensive network of with over 10,000 touchpoints, ensuring convenient access to home sample collection services, making it easier than ever to stay on top of your health monitoring requirements.

FAQs

What are the symptoms of renal artery stenosis?

• High blood pressure that's difficult to control
• Sudden worsening of previously stable blood pressure
• Declining kidney function on blood tests
• Swelling in legs, ankles, or around eyes
• Unexplained shortness of breath

What causes renal artery stenosis?

Atherosclerosis (plaque buildup) causes most cases, particularly in older adults. Fibromuscular dysplasia, which affects younger individuals—particularly women—represents another major cause.

How is renal artery stenosis diagnosed?

• Physical examination and medical history
• Blood and urine tests to assess kidney function
• Imaging studies like ultrasound, CT, or MR angiography
• Conventional angiography for detailed visualisation
• Functional tests to evaluate kidney performance

Can renal artery stenosis be cured?

While not curable, renal artery stenosis can be effectively managed through medications, angioplasty, stenting, or surgery to restore blood flow.

Does renal artery stenosis cause high blood pressure?

Yes, restricted blood flow to the kidneys triggers hormone release that significantly raises blood pressure, often creating resistant hypertension.

Is renal artery stenosis serious?

Yes, untreated renal artery stenosis can lead to kidney failure, uncontrollable high blood pressure, heart attack, and stroke.

What is the best treatment for renal artery stenosis?

Treatment depends on cause and severity, combining blood pressure medications with angioplasty, stenting, or surgery when appropriate.

Can renal artery stenosis cause kidney failure?

Yes, prolonged kidney ischemia from restricted blood flow can progress to chronic kidney disease and eventually kidney failure.

What foods should be avoided with renal artery stenosis?

• High-sodium processed foods and restaurant meals
• Excessive saturated fats and trans fats
• High-potassium foods if kidney function is declining
• Excessive protein if kidney disease is present
• Avoid foods high in phosphorus, especially in advanced kidney disease

Is surgery required for renal artery stenosis?

Surgery is rarely needed, with most patients responding well to medications and minimally invasive angioplasty procedures.