Definition

Renal artery stenosis is a narrowing or blockage of the artery that supplies blood to the kidney.

See also: Atheroembolic renal disease

Alternative Names

Renal artery occlusion; Stenosis - renal artery; Occlusion - renal artery; Fibromuscular dysplasia (FMD)

Causes, incidence, and risk factors

Renal artery stenosis is caused by:

• Atheroembolic renal disease
• Hardening of the arteries (atherosclerosis)
• Fibromuscular dysplasia of the renal artery wall
• Scar formation in the artery

Symptoms

There are usually no symptoms.

Signs and tests

The blood pressure may be high, and there may be a history of high blood pressure that doesn't respond to medication or is difficult to control. The disorder may be discovered when the doctor notes a bruit (loud whooshing sound) over the kidney during examination with a stethoscope (auscultation).

Renal artery stenosis may cause chronic renal failure if it affects both arteries of the kidneys, or if the high blood pressure associated with this condition is prolonged or severe.

Tests for renal artery stenosis:

• MRI, kidney CT scan, or kidney ultrasound may indicate that the kidney has decreased in size, or there is a decrease in blood flow through the artery because the artery has narrowed.
• Radionuclide renogram may show decreased blood flow.
• Renal arteriography shows the exact location of the blocked (stenosed) area.

This disease may also affect the results of the following tests:

• Renal perfusion scintiscan
• Urine concentration test
• Urine specific gravity

Treatment

The treatment varies depending on the extent and severity of the condition. If the stenosis results in failure of a kidney, the second kidney may take over filtering and urine production for the body. Surgical repair of the stenosed area may be possible.

A balloon angioplasty or a stent placed across the stenosis may be an alternative to surgery to open the blocked area.

Medications may be needed to control high blood pressure.

Support Groups

Expectations (prognosis)

Renal artery stenosis can eventually cause the kidney to fail if it continues to block the artery. This may lead to chronic kidney failure if only one kidney is functioning or if both kidney arteries are affected.

Renal hypertension caused by renal artery stenosis may be difficult to treat. Surgical or balloon catheter repair often successfully opens the blocked area. However, stenosis may recur.

Complications

• Chronic kidney failure
• High blood pressure (hypertension)
• Malignant hypertension

Calling your health care provider

If your history indicates a high risk for renal artery stenosis, make an appointment to see your health care provider.

Decreased urine volume may be an emergency symptom indicating kidney failure.

Prevention

Some cases of renal artery stenosis may be prevented by avoiding smoking.

Images

References

Safian RD, Textor SC. Renal-artery stenosis. N Engl J Med. 2001;344:431-442.

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

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.

Textor SC. Renovascular hypertension update. Curr Hypertens Rep. 2006;8:521-527.

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