Renal Artery Stenosis – Causes, Symptoms, Diagnosis, And Treatment
What is renal artery stenosis?
Renal artery stenosis (RAS) is narrowing of the renal arteries that carry blood to the kidneys. This condition can impede blood flow to the target kidney. Renal artery stenosis is the major cause of renovascular hypertension. This condition most often affects older people with atherosclerosis.
What causes renal artery stenosis?
The most common cause of renal artery stenosis is atherosclerosis. Atherosclerosis develops due to high cholesterol. The narrowing of the artery occurs when a sticky, fatty substance called plaque builds up on the inner lining of the arteries.
Fibromuscular dysplasia is another cause of renal artery stenosis. This condition is mostly seen in women under age 50. It tends to run in families. This condition is caused by abnormal growth of cells in the walls of the arteries leading to the kidneys. This also leads to narrowing or blockage of renal arteries.
When the arteries that carry blood to your kidneys become narrow, less blood flows to the kidneys. The kidneys mistakenly respond as if your blood pressure is low. As a result, they release hormones that tell the body to hold on to more salt and water. This causes your blood pressure to rise.
The following are the risk factors for atherosclerosis:
- High cholesterol
- High blood pressure
- Heavy alcohol use
- Cocaine abuse
- Increasing age
What are the symptoms of renal artery stenosis?
In many cases, renal artery stenosis has no symptoms until it becomes severe. High blood pressure that responds poorly to treatment is the main symptom of renal artery stenosis. Poor kidney function and severe high blood pressure in people under the age of 30 are the other symptoms of renal artery stenosis.
The following are the symptoms of renal artery stenosis:
- High blood pressure at a young age (below 30 years)
- High blood pressure that suddenly gets worse or is hard to control
- Poor functioning of the kidneys
- Narrowing of other arteries elsewhere in the body
- Pulmonary edema (sudden buildup of fluid in the air sacs of the lungs)
If there is a significant decrease in kidney function, the following symptoms may occur:
- Increased or decreased urination
- Edema (swelling) of legs, feet, or ankles and less often in the hands or face
- Generalized itching
- Dry skin
- Weight loss
- Loss of appetite
- Nausea and vomiting
- Trouble sleeping
- Trouble concentrating
- Darkened skin
- Muscle cramps
How is renal artery stenosis diagnosed?
The doctor will perform a physical exam and review the symptoms. During the examination, the doctor may hear a bruit (whooshing noise) when the stethoscope is placed over your belly area.
The doctor may order the following blood tests for diagnosis:
- Cholesterol levels
- Renin and aldosterone levels
- BUN (blood, urea, nitrogen)
- Creatinine level
- Creatinine clearance
- Potassium level
The doctor may order the following imaging tests to see if the kidney arteries have narrowed:
- Angiotensin-converting enzyme (ACE) inhibition renography
- Doppler ultrasound of the renal arteries
- Magnetic resonance angiography (MRA)
- Renal artery angiography
How is renal artery stenosis treated?
The goal of the treatment would be to prevent RAS from getting worse, to control renovascular hypertension, and to remove blockage of the renal arteries. The treatment includes lifestyle changes, medications, and surgery.
The best way to treat RAS is to make lifestyle changes that promote healthy blood vessels, including the renal arteries. Exercising regularly, maintaining a healthy body weight, and eating a healthy diet are the best ways to prevent plaque buildup in the arteries. Smokers should quit smoking to help protect their kidneys and other internal organs.
For people with renovascular hypertension, the doctor may prescribe medications to lower blood pressure and to slow the progression of kidney disease. Blood pressure-lowering medications, such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) have proven to be effective in slowing the progression of kidney disease.
Many people require two or more medications to control their blood pressure. In addition to an ACE inhibitor or an ARB, your doctor may prescribe a diuretic to help your kidneys to remove fluid from the blood. Beta blockers, calcium channel blockers, and other blood pressure medications may also be prescribed if needed.
Your doctor may also prescribe a cholesterol-lowering medication to prevent plaque buildup in the arteries. A blood-thinner, such as aspirin may also be prescribed to help the blood flow more easily through the arteries.
Your doctor may recommend surgery if renovascular hypertension does not improve with medications or the narrowing of the renal arteries is severe. The surgical procedures are performed in a hospital by a vascular surgeon (a doctor who specializes in repairing blood vessels) under anesthesia. Your doctor may recommend one of the following surgical procedures:
- Angioplasty with stenting
- Bypass surgery.
This feature is for informational purposes only and is not intended to substitute the expert guidance of a doctor. We advise seeing a doctor if you have any health concerns.