Renal Artery Stenosis: What You Need to Know

Narrowing of kidneys' blood vessels could have major consequences

Narrow renal arteries could increase your blood pressure. MediaForMedical/UIG/Getty Images


The term renal artery stenosis refers to narrowing of the vessels that supply the kidneys with blood.  Depending on the severity, it may or may not be bad enough to be concerning.  It typically takes a significant degree of stenosis to see symptoms or signs (called "clinically significant stenosis").


The kidneys have a major role in regulating the body's blood pressure.

 They do so by multiple and fairly complicated mechanisms that involve the so-called renin-angiotensin-aldosterone system (hormones that regulate blood pressure), as well as regulation of other factors including the kidneys' nervous activity, sodium and fluid retention, etc., all of which are directed towards regulation of the body's blood pressure (the details of these are beyond the scope of this article).

It is however important to know this background because once significant renal artery stenosis develops, the blood supply to the affected kidney could drop. This will typically lead to inappropriate activation of the renin-angiotensin-aldosterone system leading to high quantities of these hormones being produced. Essentially, it is akin to messing with the blood-pressure's thermostat! 

  • Hence, one of the most common features of significant renal artery stenosis is high blood pressure that could be hard to treat, sometimes referred to as resistant hypertension.
  • Blood tests could begin to show signs of damage to the kidney.  Renal artery stenosis, especially if present in both kidneys may lead to abnormal blood tests of the kidneys function, including an increase in creatinine or reduction in GFR (the kidneys' filtration rate).
  • Significant fluid retention could result, which then leads to swelling (or edema) seen in the legs, but could be more generalized as well.  In fact, one of the most severe forms of fluid retention with renal artery stenosis could actually lead to rapid fluid accumulation in the lungs in association with very high blood pressures. This condition is referred to as flash pulmonary edema.


    This is really a trick question. The more appropriate question would be, "in whom should you test for renal artery stenosis?". There was a time when once you got diagnosed with renal artery stenosis, you would get a stent placed in the renal arteries.  It was almost the most intuitive thing to do. You see narrowing of blood vessel to an organ and reduction of its blood supply.  Hence, it makes perfect sense to throw in a stent in that artery and open it up, right? Well guess what; that might not be the most appropriate thing to do in every patient. 

    This was brought out in stark contrast by the often quoted CORAL study, which showed that stenting of a stenotic kidney artery did not necessarily help the patient any more than medications alone. In fact inappropriate stenting in the bad-candidate patient could expose one to procedure related risks. 

    In other words, even if someone does have suspicious clinical findings that could suggest presence of renal artery stenosis, it might not be the most appropriate thing to test them for it if the blood pressure is already well controlled on medications, and they don't have any of the other concerning features of renal artery stenosis.

     This is because the results of the investigations done to diagnose renal artery stenosis will not necessarily change the treatment (it would remain medications-only, whether or not the person has significant renal artery stenosis).  

    However, this approach does not apply if :

    • The blood pressure remains uncontrolled in spite of maximum medical management
    • Concerning features like flash pulmonary edema are present
    • Rapidly progressive kidney failure attributed to stenosis is present
    • Fibromuscular dysplasia is present 

    In the above cases, testing for significant renal artery stenosis is warranted because revascularization (with stent or surgery) could be beneficial to the patient.  It is also important to remember that revascularization might not benefit those patients who have already sustained chronic damage and significant scarring in the kidney.  In that case, revascularization often ends up being a case of perfusing a piece of dead tissue with blood, and may not necessarily yield the results we want.


    As mentioned above, aggressive management with appropriate medications could be all that is necessary for the right patient.  This would typically require consultation with a hypertension specialist or nephrologist. Medications that are typically used include renin angiotensin inhibitors like lisinopril, losartan, etc.

    If the patient fits one of those categories where revascularization is warranted, referral to a vascular surgeon or an interventional cardiologist would be necessary.

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