Renovascular Hypertension

Definition

Renovascular hypertension is high blood pressure in 1 or both of the renal arteries that supply blood to the kidneys.

The Kidney and its Main Blood Vessels

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Causes

Renovascular hypertension is caused by renal artery stenosis, a narrowing of the artery in the kidney. This results in a decrease in blood flow to 1 or both kidneys.

Each kidney is capable of regulating the body’s blood pressure to assure that each organ has an adequate supply of oxygenated blood. Stenosis activates a cascade of hormones known as the renin-angiotensin system. This pattern increases blood pressure, which may result in renovascular hypertension. High blood pressure is a leading cause of stroke and heart attack.

The 2 most common causes of renovascular hypertension are:

• Atherosclerosis—Fatty plaque builds up in the arteries and blocks blood flow to the kidneys. This occurs mainly in men over 50 years old.
• Fibromuscular dysplasia—An inherited disorder where muscle and fibrous tissue of the renal artery wall thicken and harden into rings that block blood flow to the kidneys. This occurs mainly in young women in their 30s.

Risk Factors

Factors that may increase your chance of renovascular hypertension include:

• Smoking
• Obesity
• Advanced age
• High cholesterol
• Diabetes
• Personal or family history of cardiovascular disease
• Personal or family history of fibromuscular dysplasia

Symptoms

Problems with the renal arteries develop slowly and worsen over time. Most people do not experience symptoms of high blood pressure, so symptoms may go unnoticed.

In those that have symptoms, renovascular hypertension may cause:

• Very high and difficult to control blood pressure
• Episodes of heart failure
• Rapid kidney failure
• Newly discovered high blood pressure in men over 50 years old or young women in their 30s

Diagnosis

You will be asked about your symptoms and medical history. A physical exam will be done. Your doctor may take multiple blood pressure measurements over time and conduct blood tests to help diagnose your condition.

Kidney function can be evaluated with imaging tests. Tests may or may not use contrast material. Tests can include:

• CT angiography
• Renal ultrasound
• MR angiography
• Angiotensin-converting enzyme (ACE) inhibition renography
• Renal arteriography

Treatment

Talk with your doctor about the best treatment plan for you. Treatment options include the following:

Medications

Your doctor will first prescribe medication to help control your blood pressure. Because responses to medications vary, your doctor will monitor your blood pressure frequently and may adjust the type, combination, and/or dose of medication. Types of high blood pressure medications include the following:

• Diuretics
• Beta-blockers
• Calcium channel blockers
• Angiotensin-converting enzyme (ACE) inhibitors (except in those with both renal arteries blocked)
• Angiotensin receptor blockers
• Alpha-blockers
• Vasodilators

Interventions to Correct Renovascular Hypertension

If you have severe, uncontrolled renovascular hypertension, your doctor may suggest interventions to restore blood flow to the kidneys. Types of interventions include:

• Revascularization—A new path for blood flow to the kidneys is created by connecting a vein or tube above and below the blocked area.
• Angioplasty—A catheter with a balloon at its tip is inserted into the blocked artery. The balloon is quickly inflated and deflated to stretch open the artery to allow blood flow. The doctor may insert a small metal mesh tube (stent) into the artery to help it stay open.
• Endarterectomy—Surgery to remove the inner lining of the renal artery containing the plaque.

Prevention

To help reduce your chance of renovascular hypertension:

• If you smoke, talk to your doctor about how you can successfully quit.
• Maintain a healthy weight.
• Follow treatment plans if you have high cholesterol or blood pressure.
• Exercise regularly.
• Eat a low-fat, low-protein, low-sodium, high-fiber diet.