A health condition in which the arteries that supply the kidneys with oxygen-rich blood are narrowed is called renal artery stenosis (RAS). Commonly, people develop it due to atherosclerosis. If you suspect you have RAS, immediately contact your doctor. Without treatment, this condition can cause chronic kidney disease or even kidney failure. To treat this condition, doctors often recommend lifestyle changes, medicines, or surgery.
In normal circumstances, each person has two arteries that carry blood from the heart to the kidneys. Sometimes, one of these arteries may develop stenosis. Thus, it may lead to hypertension (high blood pressure) and other serious health conditions.
What is the Link between Renal Artery Stenosis and Peripheral Artery Disease?
While both disorders have similar characteristics, in people with RAS, the narrowing of the blood vessels occurs in the arteries that supply the kidneys. However, if you develop peripheral artery disease (PAD), the blood vessels that supply the arms and legs become narrowed. According to some studies, about 14% of people with PAD also have RAS.
In addition, some research suggests that people with chronic kidney disease, which is often caused by RAS, may be at increased risk of developing PAD. Furthermore, people who already have chronic kidney disease and PAD are at increased risk of stroke, limb loss, heart attack (myocardial infarction), and other serious health problems.
Symptoms
While most people with RAS do not experience symptoms, it usually causes reduced kidney function and hypertension. Check below some symptoms that people experience when the kidneys are not working well:
- Fatigue (extreme tiredness)
- Loss of appetite
- Nausea
- Vomiting
- Muscle cramps
- Dyspnea (shortness of breath)
- Swelling caused by fluid buildup (edema)
- Sleeping problems
- Difficulty concentrating
- Confusion
- Unusual weight loss
- Frequent urination
- Skin changes (including dry, itchy, or darkened skin)
If any of the previous symptoms occur, do not hesitate to visit a doctor.
Causes
Most RAS cases are caused by atherosclerosis (60% to 90%). The remaining cases are often caused by fibromuscular dysplasia. This disorder occurs when there is certain abnormal cell growth on the artery walls. However, fibromuscular dysplasia mostly affects females because it may occur due to genetics or hormonal imbalances.
Risk Factors
Those who have atherosclerosis are at increased risk of developing RAS. This disorder causes plaque from fat and cholesterol to stick to the walls of blood vessels. As a result, blood flow is reduced or, in severe cases, blocked. Check below for other factors that also elevate the risk of developing RAS:
- A family history of cardiovascular disease
- Diabetes
- Hypertension (high blood pressure)
- High cholesterol
- Obesity (excessive body weight)
- Age – The risk of developing renal artery stenosis increases in men over 45 and women over 55.
- Poor diet (high in Sodium, fat, and sugar)
- Smoking
What Happens if Renal Artery Stenosis is Left Untreated?
People with RAS may also experience some complications, especially if they ignore the symptoms and do not get treatment. These include:
- Kidney failure
- Coronary artery disease
- Chronic kidney disease
- Renal hypertension (increased blood pressure in the renal arteries)
- Peripheral artery disease (PAD)
- Kidney atrophy (reduced kidney size)
- Fluid retention
- Other vascular problems (including aneurysm, dissection, and others)
This document does not contain a complete list of RAS complications. However, you can consult with your healthcare professional about ways to reduce the risk or prevent previous complications.
How to Prevent Renal Artery Stenosis?
The following tips may help reduce the risk of developing RAS. For example:
- Adopt a balanced diet
- Regularly perform physical exercises
- Try to get and maintain a healthy weight
- Manage chronic health conditions (including diabetes, hypertension, and others)
- Stop smoking (if you face problems with smoking cessation, discuss it with your doctor)
Diagnosis
Sometimes, healthcare professionals diagnose this condition accidentally while performing tests for other reasons. Therefore, they may also perform additional tests and examinations when RAS is suspected. For example:
- Physical examination – During this procedure, doctors will check your blood pressure, look for swelling in the limbs, and listen to your breathing to get more clues about the disease. They may also use a stethoscope to listen as blood flows through the arteries. One of the most common indicators of RAS is unexplained hypertension.
- Kidney function tests – These include blood and urine tests used to check kidney function. When tests show increased levels of protein, creatinine, nitrogen, and other waste products in the body fluids, it may indicate poor kidney function.
- Imaging tests – The following tests are often done to check the size and how blood is flowing through the kidneys. They often perform a renal scan, duplex ultrasound, CTA (computerized tomographic angiography), or MRA (magnetic resonance angiography).
Treatment
In most cases, doctors treat RAS with lifestyle changes and medicines. In more severe cases, doctors may recommend surgery to treat arterial occlusion (blockage) and other problems.
Lifestyle Changes
The following lifestyle changes may help manage RAS and reduce high blood pressure. For example:
- Adopt a healthy diet low in fat, cholesterol, and sugar
- Aim for at least 30 minutes of physical exercise per day
- Try to get a healthy weight
- Stop smoking
- Limit or avoid alcoholic drinks
Medicines
The following medicines are often prescribed when lifestyle changes are not enough. They help treat hypertension and reduce the progression of kidney disease. Check below some examples:
- ACE (angiotensin-converting enzyme) inhibitors and ARBs (angiotensin receptor blockers) – These medications are used to block certain hormones that cause the blood vessels to narrow.
- Aspirin – This medicine is used to thin the blood, which helps it flow more easily through the arteries.
- Beta-blockers and calcium channel blockers – These medications are used to reduce high blood pressure.
- Diuretics (also known as water pills) – Diuretics are often prescribed by doctors to remove extra water from the blood.
- Statins (to reduce cholesterol)
Surgery
The following procedures are recommended by doctors in severe cases. For example:
- Angioplasty and stenting – During this procedure, surgeons will insert a catheter (a small and flexible tube with a lighted camera on the end) into the narrowed renal artery. Thereafter, they will inflate a balloon inside to widen it. Furthermore, angioplasty and renal artery stenting are the most common surgeries used to treat people with RAS.
- Renal artery bypass – This treatment is used to reroute blood flow to the kidney by bypassing the narrowed or blocked artery.
- Renal endarterectomy – During this treatment, surgeons will open the affected artery to remove plaque and other substances that limit or block blood flow.
Frequently Asked Questions
When should I contact my healthcare provider about renal artery disease?
If you experience any of the following symptoms, immediately call 911 or go to the nearest emergency room (ER). For example:
- Nausea
- Vomiting
- Confusion
- Low urine output
- Seizures
- Abdominal (belly) pain
- A metallic taste in the mouth
What is the life expectancy of someone with renal artery stenosis?
Usually, the 4-year survival rate in people with a severe form of RAS is around 48%. However, the same survival rate is about 89% in people with severe blockages but without RAS. For more details, discuss it with your doctor.
What is the main symptom of renal artery stenosis?
One of the most common symptoms of RAS is hypertension (high blood pressure) that is severe and resistant to medicines. However, they may also experience extreme tiredness, swelling, headaches, and others. Ask your healthcare provider if you have additional questions.
