Exams and Tests

If you have high blood pressure that has been resistant to medical treatment, or very difficult to control or new onset high blood pressure at a young age, your health care provider may conduct some tests to determine whether you have renal artery stenosis. These include:

• A physical exam: Your provider may listen to your abdomen for a bruit, or a swooshing sound, that may indicate narrowing of the renal arteries.
• Blood tests: These basic laboratory tests will look at the function of your kidneys, how well they are able to regulate various electrolytes in your blood and evaluate risk factors such as your cholesterol levels.
• A Doppler ultrasound: This test uses soundwaves to evaluate the size and structure of the kidney as well as the quality of blood flow in and out of the kidney. This test is very reliable, but it may be difficult to get good pictures in some patients, especially if obese. Sometimes the smaller arteries may be difficult to see as well.
• Additional imaging tests: Computed tomographic angiography (CTA) or a magnetic resonance arteriography (MRA) may also be used for diagnosis of RAS. These tests will provide 3D images of the kidneys and their blood vessels.
• Angiogram: In this procedure, a doctor places a small tube in an artery of the leg or arm. It is then advanced to the opening of the renal artery. This procedure allows the doctor to inject contrast or dye through the renal artery to show whether there is a narrowing.