Renal Artery Stenosis: Causes, Symptoms and Risk Factors

Renal artery stenosis is the narrowing of one or more renal arteries, which provide blood to the kidneys.

When your arteries narrow, your kidneys cannot receive enough blood that is high in oxygen. Your kidneys need enough blood flow to filter waste products and remove excess fluid. Reduced blood supply to your kidneys may cause renal damage and an increase in your body's blood pressure overall.

Causes Of Renal Artery Stenosis

Renal artery stenosis has two main causes, which are as follows:

• Accumulation around the renal arteries: The buildup of lipids, cholesterol, and other substances (plaque) in and on the walls of your renal arteries is known as atherosclerosis. Greater deposits may solidify, reduce blood flow, cause kidney scarring, and finally narrow the artery. Atherosclerosis, which can develop in several body areas, is the most common cause of renal artery stenosis.
• Fibromuscular dysplasia: In fibromuscular dysplasia, the muscle in the artery wall does not grow normally. This usually begins in early childhood. The renal artery may contain narrower and wider sections, which appear as beads on artery imaging.
• It is possible for the renal artery to narrow to the point that the kidney does not receive enough blood flow. This could cause high blood pressure in children.The specific cause of fibromuscular dysplasia is unknown, but it is more common in women and may be congenital (existing from birth).
• Fibromuscular dysplasia and constricted kidney arteries might impact not only your kidney arteries but also other arteries in your body.
• Renal artery stenosis is a rare side effect of other disorders such as blood vessel inflammation or an abdominal growth pressing on the arteries supplying your kidneys.

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Symptoms Of Renal Artery Stenosis

Renal artery stenosis usually shows no symptoms at all until the condition is more advanced. You could inadvertently find the problem by testing for something different. Your doctor may also be worried if you have:

• Blood pressure spikes that happen unexpectedly or worsen suddenly.
• Hypertension that develops after the age of fifty or before the age of thirty

When renal artery stenosis gets severe, additional signs and symptoms could manifest as follows:

• Elevated BP that is challenging to control a whooshing sound that your physician detects when placing a stethoscope over your kidneys and listening for blood flowing via a swollen or bruised duct.
• Deteriorating renal function while high protein levels in the urine or other signs of renal failure
• Excessive fluid and tissue consumption edema
• Treatment-resistant heart failure

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Risk Factors Of Renal Artery Stenosis

The majority of cases of renal artery stenosis are caused by narrowed kidney vessels. Constricted arteries in your kidneys and other body organs are more likely to occur if you have the following risk factors:

• Increasing age
• Increased cholesterol
• Elevated blood pressure
• Consumption of Meat
• Diabetes
• Smoking and other tobacco use,
• A family history of early heart disease
• Problems with not exercising

Diagnosis Of Renal Artery Stenosis

When making the diagnosis of renal artery stenosis, your healthcare provider could start by:

• Physical examination during which your doctor uses a stethoscope to listen for sounds that might point to a restricted renal artery over the kidney areas.
• An analysis of your previous medical records
• Tests to evaluate the function of your kidneys using urine and blood
• Tests to measure hormone levels in the blood and urine that regulate blood pressure

The diagnosis of renal artery stenosis is often made using the imaging studies listed below:

• Doppler Ultrasound: High-frequency sound waves can be used to see and check your kidneys and arteries by your doctor. Your doctor can diagnose and evaluate blood vessel blockages with the use of this treatment.
• CT scan: During a CT scan, a computer-connected X-ray machine creates a detailed image that shows cross-sectional views of the renal arteries. One can administer a dye injection to you to illustrate blood flow.
• Magnetic resonance imaging is referred to as MRA: Using radio waves and strong magnetic fields, MRA produces accurate three-dimensional (3D) images of the kidneys and renal arteries. When doing imaging, a dye injection into the arteries highlights the blood vessels.
• Renal artery imaging: With the use of a balloon or stent to open the limited section, your physician can diagnose renal artery blockage with the help of this specific type of X-ray examination. Before obtaining an X-ray, your doctor will inject a dye into the renal arteries using a long, thin tube called a catheter to better outline the arteries and show blood flow. The main goal of this test is to determine whether you might also need to have a small tube, or stent, inserted into your blood vessel to make it larger.

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Treatment Of Renal Artery Stenosis

Treatment options for renal artery stenosis include medication, lifestyle changes, and surgery to restore kidney blood flow. Oftentimes, combining multiple treatments is the best course of action. Whether you need particular therapy depends on your overall health and symptoms.

Modifications in lifestyle

If blood pressure is somewhat or significantly elevated, a healthy lifestyle that includes eating a low-salt diet, exercising frequently, and getting regular physical activity may help regulate it.

Medications

Medication is often an effective treatment, even in cases when renal artery stenosis is the primary cause of high blood pressure. Finding the right prescription, or combination of medications, may need some patience and time.

Some medications that are commonly used to treat high blood pressure include the following ones.

• Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) help dilate blood vessels and stop the body from naturally producing angiotensin II, a chemical that narrows blood vessels.
• Diuretics, sometimes known as water tablets, help the body eliminate excess salt and water.
• Calcium channel blockers help relax blood vessels; beta and alpha-beta blockers may help your heart beat more slowly and gently or dilate your blood vessels, depending on the prescription you take.
• If atherosclerosis is the cause of your renal artery stenosis, your doctor may also recommend aspirin and a cholesterol-lowering medication. The medications that are best for you will depend on your particular situation.

Surgery

 For some people, a renal artery reopening procedure may be recommended to improve blood flow to the kidney.

Results from clinical trials comparing medication with renal angioplasty and stenting for individuals with modest renal artery stenosis showed no difference in blood pressure reduction or improvement of renal function between the two treatment methods. Consider having the vessel opened if you are a patient with treatment-resistant heart failure, don't respond well to therapy alone, frequently retain fluids, or have medication intolerance issues.

The following methods can be used to treat renal artery stenosis:

• Renal angioplasty and stent implantation: A stent is placed into your blood vessel during this procedure to enlarge the constricted renal artery and maintain the vessel's walls open to better blood flow.
• Renal bypass surgery: During a bypass procedure, doctors graft a new blood vessel to the renal artery to establish a new route for blood to reach your kidneys. Sometimes, this may mean connecting the renal artery to a vascular that originates in the liver or spleen. These operations are usually performed in situations where angioplasty is not successful or when more surgeries are required.

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Complications Of Renal Artery Stenosis

Potential adverse consequences of renal artery stenosis include the following:

• Blood pressure elevation
• Renal failure requiring dialysis or a kidney transplant as a kind of treatment
• Ankles or foot edema could develop from your legs holding onto fluid.
• Sudden buildup of fluid in the lungs causing dyspnea.

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