What is Renovascular Hypertension?

Renovascular hypertension is one of the most common types of curable high blood pressure. When someone has renovascular hypertension, the arteries that bring blood to the kidneys are narrowed, resulting in less blood flow to the organs. The lack of blood tricks the kidneys into thinking that a person's blood pressure is low so that the organs send out hormones telling the body to retain both salt and water, resulting in hypertension.

There are two main causes of renal artery stenosis, or blockage of the arteries, that results in renovascular hypertension. A person's arteries can become blocked by a buildup of plaque, or fatty deposits, known as atherosclerosis. High cholesterol, a history of drug and alcohol use and abuse, and primary hypertension can lead to atherosclerosis. Atherosclerosis causes about two-thirds of all cases of renovascular hypertension and is more likely to occur in men over the age of 50.

Fibromuscular dysplasia, a growth of cells on the walls of the arteries, can also lead to renovascular hypertension. The condition is more common in women under age 50. When the cells grow, they form a ring in the main renal artery and branches of the artery, which makes it narrower, blocking blood flow. Fibromuscular dysplasia commonly runs in families. It may also be caused by the presence of certain hormones or by arteries that failed to develop properly.

Renovascular hypertension usually does not have any symptoms, just as other forms of hypertension are usually asymptomatic. When a person with renovascular hypertension goes to see a doctor for an exam, his or her blood pressure may be incredibly high. The doctor may also hear a sound called a bruit, or a whooshing noise, while listening to the patient's abdomen, particularly if the hypertension is a result of fibromuscular dysplasia. Usually the high blood pressure does not resolve when the patient begins taking medications. In some cases, the hypertension medications may lead to kidney failure.

Renal artery stenosis can be confirmed through several tests, including magnetic resonance angiography, an X-ray of the kidneys, or an ultrasound of the arteries. If blocked or narrowed renal arteries are confirmed, they are sometimes treated with angioplasty, often with the placement of a stent. Widening the artery is the most effective way to cure the hypertension, especially if it is caused by fibromuscular dysplasia and is in a younger patient. Patients for whom surgery is not an option may attempt to control their hypertension through medication and by making lifestyle changes.