Renal artery stenosis is a narrowing of the arteries that carry blood to one or both of the kidneys. Most often seen in older people with atherosclerosis (hardening of the arteries), renal artery stenosis can worsen over time, often leading to hypertension (high blood pressure) and kidney damage. With less blood reaching the kidneys , the body mistakes it for low blood pressure. This signals the kidneys to release hormones that lead to an increase in blood pressure. Over time, renal artery stenosis can lead to kidney failure.
What Are the Causes of Renal Artery Stenosis?
Most of the time, renal artery stenosis is caused by atherosclerosis, a process in which plaque made up of fats, cholesterol, and other materials builds up on the walls of the blood vessels, including those leading to the kidneys.
More rarely, renal artery stenosis can be caused by a condition called fibromuscular dysplasia, in which the cells in the walls of the arteries undergo abnormal growth. More commonly seen in women and younger people, fibromuscular dysplasia is potentially curable.
What Are the Risk Factors for Renal Artery Stenosis?
Renal artery stenosis is often found by accident in patients who are having tests for another reason. Risk factors include:
- Older age
- Being female
- Hypertension
- Vascular diseases (such as coronary artery disease and peripheral artery disease)
- Chronic kidney disease
- Diabetes
- Tobacco use
- Abnormal cholesterol levels
What Are the Symptoms of Renal Artery Stenosis?
Renal artery stenosis usually does not cause any specific symptoms. Sometimes, the first sign of renal artery stenosis is high blood pressure that is extremely hard to control, along with worsening of previously well-controlled high blood pressure, or high blood pressure that affects other organs in the body.
How Do You Diagnose Renal Artery Stenosis?
If your doctor thinks that you may have renal artery stenosis, they would order tests to either confirm or rule it out. These include:
- Blood tests and urine tests to examine kidney function
- Kidney ultrasound, which uses sound waves to show the size and structure of the kidney
- Doppler ultrasound, which measures the speed of blood flow through the arteries supplying the kidney
- Magnetic resonance arteriogram and computed tomographic (CT) angiography, imaging studies that use a special dye (contrast medium) to produce a 3D image of the kidney and its blood vessels
- CT angiogram, which shows detailed images of the heart and the blood vessels that go to the heart, lungs, brain, kidneys, head, neck, legs, and arms
If these noninvasive tests do not help, doctors may order a more precise but invasive test called a renal arteriography, in which images are taken while a contrast dye is injected through a catheter inserted into an artery through the groin or arm.
How Is Renal Artery Stenosis Treated?
Initial treatment for renal artery stenosis is often medication. The condition may require three or more different drugs to control high blood pressure. Patients may also be asked to take other medications, such as cholesterol-lowering drugs and aspirin.
For a small number of people, treatments such as angioplasty, often with stenting or surgery, may be recommended. With angioplasty, a catheter is inserted into the body through a blood vessel and guided to the narrowed or blocked renal artery. A balloon on the catheter is then inflated to open up the inside of the artery. A stent can then be placed to keep the area open.
Some patients may need surgery to bypass the narrowed or blocked portion of the artery and/or to remove a nonfunctioning kidney. But this procedure is not often done.
If you're diagnosed with renal artery stenosis, it's important to discuss the risks of the different treatments with your doctor. The side effects of blood pressure medications may include dizziness, sexual problems, headache, and cough. Complications of angioplasty include bruising, bleeding, further kidney damage, and the possibility that the arteries can close again.
