What is renovascular hypertension?
Renovascular hypertension is high blood pressure caused by the narrowing of the arteries that carry blood to the kidneys. Because the kidneys are not getting enough blood, they react by making a hormone that makes the blood pressure rise.
This condition is a treatable form of high blood pressure when properly diagnosed.
What is high blood pressure?
Blood pressure is the force of blood against the artery walls as the heart pumps blood through the body. A reading of 120/80, or “120 over 80,” is normal. A reading of 140/90 or above is considered high blood pressure. Blood pressure should be checked regularly. Ask the doctor what an appropriate, or safe, blood pressure reading is best.
How are the kidneys involved in renovascular hypertension?
The renal (kidney) arteries carry blood rich in oxygen and nutrients from the heart to the kidneys. If the kidneys do not get enough blood or oxygen, it may be because these renal arteries are narrowed, a condition called renal artery stenosis.
Atherosclerosis, or hardening of the arteries, is the most common cause of renal artery stenosis. Plaque, made up of fat, cholesterol, calcium, and other substances, builds up inside the arteries and causes them to harden and narrow (stenosis). Plaque can block, either partially or totally, the blood's flow through an artery in the heart, brain, pelvis, legs, arms, or kidneys.
The other cause of renal artery stenosis is fibromuscular dysplasia (FMD). While the cause of FMD is not clear, it is different in that it is not caused by plaque build-up, but rather narrowing of the blood vessel walls themselves. FMD is more common in women and should be considered in younger people who develop high blood pressure.
How does high blood pressure hurt the kidneys?
High blood pressure puts increased stress on the blood vessels in the kidneys, including the filtering units that are responsible for cleaning the blood. Over time, these blood vessels can thicken, similar to other parts of the body, and the filtering units can form scars. Both of these changes can lead to the kidneys not working properly (chronic kidney disease) and stop doing their job—removing wastes and extra fluid from the body. When the kidneys don’t work well (chronic kidney disease) they can cause further increases in blood pressure by releasing certain hormones or by causing retention of salt and water in the body.
High blood pressure is one of the leading causes of kidney failure.
What symptoms or signs are seen with renovascular hypertension?
Although renovascular hypertension is hard to diagnose and usually has no symptoms, be aware of these signs:
- High blood pressure that is not controlled on 3 or more medications at their max doses, including a diuretic
- High blood pressure at a young age
- Stable high blood pressure that suddenly gets worse or is difficult to control
- Kidneys that are not working well, which may occur suddenly
- Narrowing of other arteries in the body, such as to the legs, the brain, the eyes, and elsewhere
- Sudden buildup of fluid inside the lungs, called pulmonary edema