The renal arteries are the blood vessels that carry blood to the kidneys. Renal artery stenosis (renal artery narrowing) is most often caused by atherosclerosis or a specific fibrous disease of the arteries (called fibromuscular dysplasia). When a renal artery is clogged, blood flow to the kidneys is affected and this can result in slow but progressive damage to the kidneys and hypertension. 

Assessment of the kidney arteries is done using ultrasound, CT scanning or MRI.

Stenting (if deemed appropriate) opens the blockage and restores normal blood flow. A catheter is inserted through a groin blood vessel into the aorta, the main artery coming from the heart. The catheter is advanced to the renal arteries and contrast (dye) is used to confirm and localise the narrowing after which this is dilated (stretched open) using a balloon-tipped catheter before a mesh-like tube (stent) is deployed to scaffold the blood vessel open and prevent it from collapsing again with time.