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Renal Artery Stenosis

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Medical Author:

Siamak T. Nabili, MD, MPH

Siamak T. Nabili, MD, MPH

Dr. Nabili received his undergraduate degree from the University of California, San Diego (UCSD), majoring in chemistry and biochemistry. He then completed his graduate degree at the University of California, Los Angeles (UCLA). His graduate training included a specialized fellowship in public health where his research focused on environmental health and health-care delivery and management.

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Medical Editor:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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What are the renal arteries?

Renal refers to anything related to the kidneys. Renal arteries carry blood from the heart to the kidneys. They branch directly from the aorta (the main artery coming off the heart) on either side and extend to each kidney. These arteries take a very large volume of blood to the kidneys to be filtered.

The heart pumps out approximately 5 liters of blood per minute, and about 1-1.5 liters (25%) of the total volume of blood pumped by the heart passes through the kidneys every minute.

What is renal artery stenosis?

Renal artery stenosis (narrowing) is a decrease in the diameter of the renal arteries. The resulting restriction of blood flow to the kidneys may lead to impaired kidney function (renal failure) and high blood pressure (hypertension), referred to as renovascular hypertension, or RVHT ("reno" for kidney and "vascular" for blood vessel). Renal artery stenosis is a major cause of RVHT and accounts for 1%-10% of the 50 million cases of hypertension in the United States.

Renovascular hypertension occurs when the artery to one of the kidneys is narrowed (unilateral, or one-sided, stenosis), while renal failure occurs when the arteries to both kidneys are narrowed (bilateral, or two-sided, stenosis). The decreased blood flow to both kidneys increasingly impairs renal function.

What are the causes of renal artery stenosis?

The majority of renal artery stenosis is caused by atherosclerosis (hardening and narrowing of blood vessel wall from the inside) similar to the process that occurs in blood vessels in the heart and other parts of the body.

Risk factors for atherosclerosis include:

• high cholesterol levels
  
  
• high blood pressure
  
  
• age
  
  
• cigarette smoking
  
  
• diabetes

Less common causes of renal artery stenosis are fibromuscular dysplasia of the vessels (narrowing of the vessel due to internal thickening of the blood vessel wall), arteritis (inflammation of the blood vessel), or dissection (tearing and division of the blood vessel wall).