The kidneys are responsible for removing waste, or toxins, from the blood. They also regulate the body’s blood volume and pressure. The renal arteries carry blood to the kidneys.
If blood flow is decreased or flowing at a lower pressure, the kidneys interpret this to mean the blood volume and/or blood pressure within the rest of the body is low. Your kidneys try to correct this by releasing hormones that cause blood pressure to rise, and they will begin to retain more salt and fluid to increase blood volume.
In renal artery stenosis (RAS), blood flow is decreased because of a narrowing of the renal artery. The lower blood flow is misread by the kidneys, which respond by releasing hormones to raise blood pressure and volume. This type of high blood pressure is called renovascular hypertension and may require three or more medicines to control.
The renal arteries typically narrow from one of two causes:
- development of plaque, or atherosclerosis, in the vessel
- abnormal cell growth in the artery wall
Your health care provider may suspect RAS if your blood pressure is not controlled with at least three different blood pressure medications at escalating doses. He or she likely will order blood tests, and imaging tests to determine the size and structure of your kidneys, and to examine the blood flow to them.
You can reduce your risk of developing renovascular hypertension by keeping your blood vessels healthy. Some things you can do include: Quit smoking if you smoke; be physically active; lose weight if you are overweight; and see your physician on a regular basis to make sure your blood pressure is not high. Use this condition center to learn more about RAS diagnosis, treatment and prevention.