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Renovascular hypertension is high blood pressure that is caused by narrowing (stenosis) of one or both of the arteries, called the renal arteries, that supply blood to the kidneys. Narrowing of the renal arteries reduces blood flow to the kidneys. This is a potentially serious condition that requires care from your doctor.

Each kidney is capable of regulating the body’s blood pressure to assure that each organ has an adequate supply of oxygenated blood. This happens by activating a cascade of hormones known as the renin-angiotensin system.

Renal artery stenosis triggers the release of these hormones, which then becomes a cause for hypertension (high blood pressure). Since hypertension is a leading cause of strokes and heart attacks , this is a serious condition that requires diagnosis and treatment.

The Kidney and Its Main Blood Vessels

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There are many diseases that can cause narrowing of the renal arteries. The two most common causes are atherosclerosis and fibromuscular dysplasia.

• Atherosclerosis—often called “hardening of the arteries,” results when fatty plaque builds up in the arteries and blocks blood flow to the kidneys. This occurs mainly in men over 50.
• 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 females in their 30s.

A risk factor is something that increases your chance of getting a disease or condition. The following factors increase your chance of developing atherosclerosis or fibromuscular dysplasia, which are the leading causes of renovascular hypertension.

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

Because problems with the renal arteries develop slowly and worsen over time, and most people do not experience symptoms of high blood pressure, you may not notice any symptoms.

However, the following symptoms may be signs of renovascular hypertension. If you experience any one of them, talk to your doctor:

• Very high and difficult to control blood pressure
• A “whooshing” sound in the abdomen, heard with a stethoscope
• Episodes of heart failure
• Rapid kidney failure
• Newly discovered hypertension in men over 50 years old or young women in their 30s

Your doctor will ask about your symptoms and medical history, and perform a physical exam. You likely will be referred to a doctor who is a kidney specialist (nephrologist). Your doctor may take multiple blood pressure measurements over time and conduct blood tests to help diagnose your condition.

If you have renovascular hypertension, your doctor may conduct any of the following tests to see the amount of narrowing in the kidney arteries:

• Renal arteriography—a dye is injected into the kidney arteries and an x-ray is then taken of them
• Doppler ultrasound —a procedure that uses sound waves to examine various parts of the body
• Magnetic resonance angiography —a procedure that produces very detailed two- and three-dimensional images of the arteries by using radio waves in a strong magnetic field instead of using x-rays
• Angiotensin-converting enzyme (ACE) inhibition renography—a noninvasive imaging procedure that tests for the presence of renovascular hypertension and renal artery stenosis
• CT angiography—a procedure that uses high resolution CT scan images and contrast injected into a vein to give an accurate picture of the renal arteries. This procedure is rapidly replacing renal arteriography.

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

To help reduce your chances of getting renovascular hypertension, take the following steps:

• Stop smoking.
• Maintain a healthy weight.
• Maintain healthy cholesterol and lipid levels.
• Exercise regularly.
• Eat a low-fat, low-protein, low-sodium, high-fiber diet.