Renal Artery Stenting
The kidneys are critical for filtering waste from the bloodstream and for regulating blood pressure. Blockages and narrowing of the arteries (renal arteries) can reduce blood flow to the kidneys and thus compromise kidney function. The narrowing is called renal artery stenosis, and like atherosclerosis (hardening of the arteries), it is caused by the formation of plaque (material that builds up on the inner surface) on the artery walls from excess cholesterol, fat and calcium. Another common cause of renal artery stenosis includes an abnormal growth of cells in renal artery walls (fibromuscular dysplasia). Renal artery narrowing usually causes no obvious symptoms. However, high blood pressure that does not respond to treatment may be an indication that renal arteries are narrowed. Physicians can usually hear a whooshing sound (bruit) when listening to the abdomen with a stethoscope. Statistics show that untreated renal artery stenosis will get worse in nearly half of all patients - with a higher risk for women - and can lead to kidney failure.
Physicians will sometimes recommend surgery to remove any blockage in the arteries (endarterectomy) or bypass surgery of the artery, but balloon angioplasty and stenting are most often the preferred treatment options. Patients undergoing angioplasty or stenting are given a sedative, but not put to sleep. They are also given medications to prevent blood clots. The wire-like catheter is placed in the bloodstream through an artery in the arm or groin and is threaded into the renal artery with the aid of live x-ray images (fluoroscopy). Contrast dye is injected into the artery at the blockage so the physician can see the blood flow on the x-ray monitor. A balloon on the tip of a catheter is then expanded to open the plaque-clogged area of the artery. A stent - a tubular-shaped metal mesh support or mini scaffold - is then expanded to prop open the opened artery and to keep it from collapsing.
Complications and risks from renal artery balloon angioplasty and stenting can include the following:
Plaque eventually rebuilding around the stent (restenosis)
- Tearing of the artery wall by the catheter
- Allergic reaction to the iodine-based contrast dye used during the procedure
- Contrast causing damage to the kidneys
MDCA cardiologists perform these procedures in a full catheterization laboratory using state-of-the-art heart catheter equipment. They are experienced in assessing the full spectrum of heart conditions and use cardiac catheterization as an important tool to assess a patient's overall heart health and to direct his or her treatment. To make an appointment with an MDCA cardiologist experienced with renal artery stenting, please call 713-441-1100 (Pearland patients, please call 713-441-9909).