Renovascular hypertension

Definition

Renovascular hypertension is high blood pressure due to narrowing of the arteries that carry blood to the kidneys.

See also:

• Atheroembolic renal disease
• Hypertension
• Malignant hypertension

Alternative Names

Renal hypertension; Hypertension - renovascular; Renal artery occlusion; Stenosis - renal artery

Causes, incidence, and risk factors

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 give off 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 hardening of the arteries (atherosclerosis) from high cholesterol.

• Atherosclerosis (hardening of the arteries) 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) aretery.
• Risk factors for atherosclerosis are: high blood pressure, smoking, diabetes, high cholesterol, heavy alcohol use, cocaine abuse, and increasing age.

Fibromuscular dysplasia is another cause of renal artery stenosis, particularly in women under age 50. It tends to run in families. Fibromuscular dysplasia is caused by abnormal growth or development of cells in the walls of the arteries leading to the kidneys. This also leads to narrowing or blockage of these arteries.

Symptoms

Usually, high blood pressure causes no symptoms. Occasionally you may have a mild headache. If your headache is severe, or if you have any of the symptoms below, see a doctor right away. These may be a sign of malignant hypertension.

• Blood in urine
• Confusion
• Crushing, angina-like chest pain
• Ear noise or buzzing
• Irregular heartbeat
• Nosebleed
• Tiredness
• Vision changes

Signs and tests

People with renovascular hypertension usually have severe, difficult-to-control high blood pressure. They may have a history of high blood pressure that is hard to control or does not get better with medication.

Your doctor may hear a "whooshing" noise, called a bruit, when placing a stethoscope over your belly area.

Other signs of this disease include:

• Acute kidney failure occurs when starting blood pressure medicines called ACE-I or ARBs
• Episodes of heart failure (flash pulmonary edema)
• Hypertension in an elderly patient whose blood pressure was previously well controlled
• Rapid progression of kidney failure

There may be signs of complications, such as:

• Hypertensive retinopathy
• Left ventricular hypertrophy (swelling of the heart)

Your doctor may order blood tests to check your renin and aldosterone levels. Imaging tests may be done to see if the kidney arteries have narrowed. They include:

• Angiotensin converting enzyme (ACE) inhibition renography
• Doppler ultrasound of the renal arteries
• Magnetic resonance angiography (MRA)
• Renal arteriography

Treatment

High blood pressure caused by narrowing of the arteries that lead to the kidneys (renovascular hypertension) is often difficult to control.

Medications may be used 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.

• 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.
• Everyone should keep their blood pressure below 140/90 mmHg. If you have diabetes or have had a stroke, your blood pressure should be below 130/80 mmHg. Ask your doctor what blood pressure 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.

To help prevent hardening of the arteries, make the following lifestyle changes:

• Avoid fatty foods. Follow a healthy, low-fat diet. See Heart disease and diet.
• Check with your doctor about an exercise program.
• Do NOT drink more than 1 or 2 alcoholic drinks a day.
• Quit smoking. Smoking increases the risk of forming clots.

Further treatment depends on what causes the narrowing of the kidney arteries.

Complications

• Early death
• Hypertensive heart disease
• Heart attack
• Congestive heart failure
• Blood vessel damage
• Kidney damage
• Kidney failure
• Stroke
• Loss of vision

Calling your health care provider

Call for an appointment with your health care provider if you think you have high blood pressure.

Call your health care provider if you have renovascular hypertension and symptoms get worse or do not improve with treatment. Also call if new symptoms develop.

Prevention

Preventing atherosclerosis may prevent the development of rental artery stenosis.

Lifestyle changes may reduce your risk of high blood pressure. Lose weight if you are overweight. Excess weight makes the heart work harder. Check with your doctor before starting a rigorous exercise program.

Changes in your diet may help to control your blood pressure. Reduce the amount of salt (sodium) you use. Salt, MSG, and baking soda all contain sodium.

See also: Heart disease and diet

References

Balk E, Raman G, Chung M, Ip S, Tatsioni A, Alonso A, et al. Effectiveness of management strategies for renal artery stenosis: a systematic review. Ann Intern Med. 2006;145:901-912.

DuBose TD Jr, Santos RM. Vascular disorders of the kidney. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 126.

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.

Victor RG. Arterial hypertension. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007.

White CJ. Catheter-based therapy for atherosclerotic renal artery stenosis. Circulation. 2006;113:1464-1473.

Wolff T, Miller T. Evidence for the reaffirmation of the U.S. Preventive Services Task Force recommendation on screening for high blood pressure. Ann Intern Med. 2007;147(11):787-791.