Kidney artery blockages by atherosclerotic plaques, or “renal artery stenosis”, is very common, afflicting millions of Americans, up to 7% of those over the age of 65. Most often, kidney artery blockages are implicated in high blood pressure, especially difficult-to-treat high blood pressure. Occasionally, it may result in poor kidney function or even kidney failure requiring dialysis.
The kidneys are the most important organ that control blood pressure. When kidney arteries become blocked, the kidneys assume that the overall blood pressure in the body is too low, and they make hormones to drive up the blood pressure. This can result in dangerously high blood pressure in the rest of the body.
Blood pressure control is very important to reduce cardiovascular events like heart attacks, stroke, heart failure and death, and also can cause worsening kidney function. Reduction of systolic blood pressure by less than 10% when elevated can reduce the risk of these events by up to 1/3. If blood pressure is not normal (systolic less than 140, or less than 135 if diabetes is present), efforts should be made to reduce it. If renal artery stenosis is present, those efforts may include opening up kidney artery blockages.
Diagnosis
There are few signs or symptoms of kidney artery blockages and often the diagnosis is missed. Patients with very high or difficult to control blood pressure, such as those requiring more than 2 blood pressure medications, should be considered for evaluation, especially if they have other risk factors for atherosclerotic disease (smoking history, high cholesterol, diabetes, or known atherosclerotic disease in other circulations like the coronary arteries, carotid arteries, or leg arteries). Fortunately, a noninvasive test, magnetic resonance angiography, is highly sensitive for detecting kidney artery blockages.
Treatment
If it is necessary to open up blocked kidney arteries, it is usually possible to do so with minimally invasive, catheter-based means using fluoroscopic (X-ray) guidance. Often this is done on an outpatient basis, or in many cases with an overnight admission to the hospital.
Research
The Interventional Radiology department at Rhode Island Medical Imaging supports and participates in the National Institutes of Health CORAL Study (Cardiovascular Outcomes with Renal Atherosclerotic Lesions, www.coralclinicaltrial.org), and if you qualify for the study would be happy to discuss participation.