Doctor's Notes on Renal Artery Stenosis
Renal artery stenosis describes the narrowing of the renal (kidney) arteries, which can lead to high blood pressure (hypertension). This occurs when one of the renal arteries narrows causing decreased blood flow to the kidney and to the macula densa (the specialized, blood-pressure sensing cells in the kidney). These cells falsely presume the low blood flow is occurring throughout the body and that overall blood pressure is too low. This triggers to increase blood pressure in response.
Renal artery stenosis causes high blood pressure, which is often referred to as the "silent killer" because there are often specific symptoms. Over time the elevated blood pressure stresses the body’s major organs, and becomes a risk factor for heart attack and stroke. Symptoms of renal artery stenosis may occur due to damage to the kidneys, and can include fatigue, feeling unwell (malaise), and slight confusion due to a buildup of waste products in the body.
Renal Artery Stenosis Symptoms
Blood pressure elevation with renal artery stenosis is no different; however, the decreased blood flow the kidney(s) over time may cause damage to the kidney(s). Decreased renal function (azotemia), may present with symptoms of fatigue, malaise, and/or slight confusion due to a gradual buildup of waste products in the body.
Your physician may be concerned about renal artery stenosis if high blood pressure has its initial presentation in a person older than age 50 or in a person under the age of 30.
The physical examination may give a clue if a bruit (a rustling sound produced by turbulent blood flow) is heard when your physician listens to the abdomen. If an artery is narrowed, it may cause turbulence as blood flows through the narrowing, causing a noise, like the rapids in a river. This noise is called a bruit.
Renal artery stenosis may also be considered a cause of elevated blood pressure if multiple anti-hypertension medications have failed to control high blood pressure.
Renal Artery Stenosis Causes
The most common cause of renal artery stenosis is atherosclerosis, the same condition that causes narrowing of the arteries in coronary heart disease and stroke, and the risk factors are the same as well. Cholesterol plaques build up along the walls of the renal artery and gradually cause narrowing. Risk factors for renal artery stenosis include:
Other causes of stenosis (narrowing) of the renal artery include:
Your arteries should be sturdy, springy, and smooth to move blood easily from your lungs and heart, where it gets oxygen, to your organs and other tissues. High blood pressure, or HBP, pushes too hard on your artery walls. This damages the inside and causes fat, or "plaque," to collect. That plaque makes your arteries more stiff and narrow, so they can't do their job as well.
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.