Renal Artery Stenosis
Renal artery stenosis is a narrowing of 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 and often leads to hypertension (high blood pressure) and kidney damage. The body senses less blood reaching the kidneys and misinterprets that as the body having low blood pressure. This signals the release of hormones from the kidney that lead to an increase in blood pressure. Over time, renal artery stenosis can lead to kidney failure.
Causes of Renal Artery Stenosis
More than 90% 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 dyplasia, in which the cells in the walls of the arteries undergo abnormal growth. More commonly seen in women and younger people, fibromuscular dyplasia is potentially curable.
Risk Factors for Renal Artery Stenosis
Renal artery stenosis is often found by accident in patients who are undergoing tests for another reason. Risk factors include:
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 elevated blood pressure that affects other organs in the body.
Diagnosis of Renal Artery Stenosis
If your doctor suspects that you have renal artery stenosis, he or she may order tests to either confirm suspicions or rule it out. These include:
- Blood tests and urine tests to evaluate kidney function
- Kidney ultrasound, which uses sound waves to show the size and structure of the kidney
- Doppler ultrasound, which measures blood-flow speed in arteries to the kidney
- Magnetic resonance arteriogram and computed tomographic angiography, imaging studies that use a special dye (contrast medium) to produce a 3-D image of the kidney and its blood vessels