Renal artery angioplasty is a procedure to widen the opening of the renal arteries that supply blood to the kidney. Narrowing of the renal artery (renal artery stenosis) is the leading cause of this artery obstruction. Renal angioplasty is usually done to protect the kidney from further damage due to loss of the blood supply. The blood supply may be slowly reducing over a long time or may have happened suddenly causing kidney pain. Doctors know that there is a problem with part of your circulation. You may already have had an angiogram, which has shown a blockage in an artery. Dr Kamal Gupta A specially trained doctor has special expertise in using x-ray equipment, and also in interpreting the images produced. They need to look at these images while carrying out the procedure. If you have any allergies, you must let your doctor know. If you have previously reacted to intravenous contrast medium, the dye used for kidney x-rays and CT scanning, then you must also tell your doctor about this.