Renal artery stenosis is a narrowing of the artery that brings oxygen-rich blood to the kidneys. This narrowing is typically because of cholesterol build up in the artery wall that is called atherosclerosis. The clinical manifestation of renal artery stenosis is typically elevated blood pressure.
History and Physical Exam
The combination of history and physical exam is the most important test that can be done, and it is the first step in determining whether further testing is needed. The patient will be able to discuss his problems with the physician, and the physician will be able to ask specific questions about the patient's medical past and current medications. The physician should also perform a detailed physical that will include checking the blood pressure and listening to the heart, lungs and abdomen. Listening to the abdomen is especially important, as the physician may be able to hear what is called a bruit, a high-pitched sound that is created when blood moves quickly through a narrowed space.
Urinalysis
A urine sample may be given while in the physician's office, and the physician will be able to use a special meter to check if there are large amounts of protein in the urine, as this may be a sign that there is a problem with the kidney's ability to adequately filter the blood. This may warrant further testing with ultrasound.
Renal Ultrasound
Physicians attempt to start the diagnostic work up with the least invasive test possible, which is why the history is always the first step. An ultrasound is another non-invasive test that, when interpreted by a radiologist, a doctor specialized in medical imagining, can give detailed information about the size of the kidneys and the blood flowing into them. This test simply requires the patient to lay on his side and to have a jelly, that enhances the sound waves, placed on the skin, and the operator then puts a probe onto the skin.
Angiography
If renal artery stenosis is suspected on an ultrasound, then the physician will do a more invasive test that will confirm the diagnosis and also allow for treatment at the same time. This next test is an angiogram. The doctor will put a needle into the groin and then thread wires into the artery and up to the renal arteries. Using special X-rays, known as fluoroscopy, the doctor will be able to inject dye into the artery and see if there is a stenosis. If this is confirmed, the doctor will be able to use a balloon to open the artery and a stent to keep the artery open.
References
- "Harrison's Principles of Internal Medicine"; Ed. Kasper, Braunwald, Fauci, Hauser, Longo, Jameson; 16th ed; 2005
