Renal Artery Occlusion

Definition

Renal artery occlusion is a blockage of the major arteries that supply blood to the kidneys caused by thrombosis or embolism.

Description

Renal artery occlusion occurs when the flow of blood from the arteries leading to the kidneys becomes blocked by a blood clot or cholesterol emboli. The lack of oxygenation can lead to necrosis (tissue death) and ultimately, chronic kidney failure.

Causes and symptoms

Renal arterial occlusion occurs when a thrombus or embolism (blood clot or cholesterol plaque) breaks free and blocks the arteries leading to one or both kidneys.

Symptoms of an acute renal arterial occlusion may include:

• hypertension
• fever
• sudden pain in the lower back or flank
• nausea and vomiting
• protein and/or blood in the urine

An individual with renal arterial occlusion may have no overt symptoms, particularly if only one kidney is affected or if the blockage is only partial. Health problems from secondary complications such as chronic kidney failure may be the first indication that something is wrong.

Diagnosis

The high blood pressure that is sometimes associated with a renal artery blockage may be the first sign that it is present, particularly if the hypertension is not responding to standard treatment. Urine and blood tests may or may not be useful in diagnosing this condition. Blood tests may show an elevated plasma creatinine level. If kidney tissue infarction (cell death caused by a lack of blood supply) has occurred, lactic dehydrogenase (LDH) may also be present in the urine and blood.

An arteriogram, an x-ray study of the arteries that uses a radiopaque substance, or dye, to make the arteries visible under x ray, may also be performed. This test is used with caution in patients with impaired kidney function, as the contrast medium can cause further kidney damage. In patients with whom this is not an issue, a spiral computed tomography (CT) scan with contrast medium may also be used.

Treatment

Occlusions may be treated with anticoagulant (blood thinning) or thrombolytic (clot destroying) drugs. If the blockage is significant, surgical intervention or angioplasty may be required. Between 1996 and 2000, the number of these procedures performed on Medicare patients more than doubled, said a 2004 report.

KEY TERMS

Angioplasty— A non-surgical procedure that uses a balloon-tipped catheter to open a blocked artery.

Artherosclerotic plaque— A deposit of fatty and calcium substances that accumulate in the lining of the artery wall, restricting blood flow.

Atrophy— Cell or tissue wasting or death.

Chronic kidney failure— End-stage renal disease (ESRD); chronic kidney failure is diagnosed as ESRD when kidney function falls to 5-10% of capacity.

Embolism— Blood vessel obstruction by a blood clot or other substance (i.e., air).

Thrombus— Formation of a blood clot within the vascular system. A thrombus becomes an embolism if it breaks away and blocks a blood vessel.

Alternative treatment

Renal arterial occlusion is a serious and potentially life-threatening condition, and should always be treated by a healthcare professional familiar with the disorder.

Prognosis

The outcome of renal arterial occlusion depends on the speed with which it is treated. Once the blood supply is minimized or cut off to the kidney, tissue death soon results, ultimately leading to chronic kidney failure (end-stage renal disease).

Prevention

Atherosclerosis may encourage the formation of cholesterol emboli, a potential cause of renal artery occlusion. Strategies for avoiding vascular disease include eating right, maintaining a desirable weight, quitting smoking, managing stress, and exercising regularly. People prone to emboli from blood clots can take blood thinning drugs to prevent potential emboli from loding in the renal artery.

Resources

PERIODICALS

Bloch, M. J., and T. Pickering. "Renal Vascular Disease: Medical Management, Angioplasty, and Stenting." Seminars in Nephrology 20, no. 5 (September 2000): 474-88.

"Explosive Growth Seen in Renal Artery Interventional Procedures." Heart Disease Weekly September 26, 2004: 20.

Truelove, Christiane. "First for Pulmonary Embolism." Med Ad News August 2004: 82.

ORGANIZATIONS

American Kidney Fund (AKF). Suite 1010, 6110 Executive Boulevard, Rockville, MD 20852. (800) 638-8299. 〈http://www.arbon.com/kidney/〉.

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Natcher Building, 6AS-13K, 45 Center Drive, Bethesda, MD 20892-6600. 〈http://www.niddk.nih.gov〉.

National Kidney Foundation. 30 East 33rd Street, New York, NY 10016. (800)622-9020. 〈http://www.kidney.org〉.