When the arteries that carry blood to your kidneys become narrow, less blood flows to the kidneys. The kidneys mistakenly respond as if your blood pressure is low and make hormones that tell the body to hold on to more salt and water. This causes your blood pressure to rise.
Renal artery stenosis is a narrowing or blockage of the artery that supplies blood to the kidneys.
The most common cause of renal artery stenosis is a blockage in the the arteries due to high cholesterol. This problem occurs when a sticky, fatty substance called plaque builds up on the inner lining of the arteries. The plaque may slowly narrow or even block the renal (kidney) artery.
Risk factors for atherosclerosis include high blood pressure, smoking, diabetes, high cholesterol, heavy alcohol use, cocaine abuse, and increasing age.
Fibromuscular dysplasia is another cause of renal artery stenosis. It is often seen in women under age 50 and tends to run in families. It is caused by abnormal growth of cells in the walls of the arteries leading to the kidneys. This also leads to narrowing or blockage of these arteries.
People with renovascular hypertension may have a history of high blood pressure that is severe and hard to control with medication.
Symptoms of renovascular hypertension include:
High blood pressure at a young age
High blood pressure that suddenly gets worse or is difficult to control
Kidneys that are not working well, which often occurs suddenly
Narrowing of other arteries in the body, such as to the legs, the brain, the eyes and elsewhere
If you have a severe headache, nausea or vomiting, bad headache, confusion, changes in your vision, or nosebleeds you may have a severe and dangerous form of high blood pressure called malignant hypertension.
Signs and tests
The health care provider may hear a "whooshing" noise, called a bruit, when placing a stethoscope over your belly area.
High blood pressure caused by narrowing of the arteries that lead to the kidneys (renovascular hypertension) is often difficult to control.
Medications are needed to help control blood pressure. There are a variety of high blood pressure medications available. You and your doctor will decide which type is best for you. often more than one type may be needed.
Everyone responds to medicine differently. Your blood pressure should be checked frequently. The amount and type of medicine you take may need to be changed from time to time.
Ask your doctor what blood pressure measurement is appropriate for you.
Take all medicines in the exact way your doctor prescribed them.
Have your cholesterol checked and treated. If you have diabetes, heart disease, or hardening of the arteries somewhere else in your body, your "bad" (LDL) cholesterol should be lower than 100 mg/dL.
Lifestyle changes are important:
Eat a heart-healthy diet.
Exercise regularly, at least 30 minutes a day (check with your doctor before starting).
If you smoke, quit. Find a program that will help you stop.
Limit how much alcohol you drink: 1 drink a day for women, 2 a day for men.
Limit the amount of sodium (salt) you eat. Aim for less than 1,500 mg per day. Check with your doctor about how much potassium you should be eating.
Reduce stress. Try to avoid things that cause stress for you. You can also try meditation or yoga.
Stay at a healthy body weight. Find a weight-loss program to help you, if you need it.
Further treatment depends on what causes the narrowing of the kidney arteries.Your doctor may recommend a procedure called angioplasty with stenting.
These procedures may be an option if you have:
Severe narrowing of the renal artery
Blood pressure that cannot be controlled with medicines
Kidneys that are not working well and are becoming worse.
However, experts are not certain which patients should have these procedures.
If your blood pressure is not well controlled, you are at risk for the following complications:
Dworkin LD, Murphy T. Is there any reason to stent atherosclerotic renal artery stenosis? Am J Kidney Dis. 2010 Aug;56(2):259-63.
U.S. Preventive Services Task Force. Screening for high blood pressure: U.S. Preventive Services Task Force reaffirmation recommendation statement. Ann Intern Med. 2007;147(11):783-786.
Melissa B Bleicher, MD, Division of Renal, Electrolyte, and Hypertension, Hospital of the University of Pennsylvania, Philadelphia, PA. Review provided by VeriMed Healthcare Network, and David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.