Renal Artery: Angioplasty and Stenting

The kidney serves as a filter to rid the body of waste materials, excess fluids from the blood, excrete urine, and regulate water, electrolytes, and the PH of blood. Almost 1/3 of the body’s blood flow goes to the kidneys. Blood pressure is also regulated by the kidneys. The renal arteries carry blood to the kidneys.

Renal Artery Disease:

  • This disease occurs in the blood vessels leading to the kidneys. Fatty deposits and/or calcium (also known as plaque), builds up on the inside arteries as we age. This process is known as Atherosclerosis.
  • Atherosclerosis is a progressive disease that involves hardening and narrowing of the arteries due to plaque build-up. This can worsen, causing artery stenosis (narrowing of the artery), total blockage, or total occlusion of an artery.
  • If narrowing of the renal artery is significant, the kidney incorrectly senses the blood pressure is too low. This signals the body to increase the blood pressure, which causes hypertension. This type of blood pressure increases the rate atherosclerosis progresses, in turn increasing strain on the heart.
  • Blood flow being restricted from the kidney reduces the ability to remove waste and fluids from the body, this is renal insufficiency. Renal Artery stenosis leads to kidney failure.

Risk Factors:

  • Being overweight
  • Lack of regular exercise
  • Eating a high-fat diet
  • Uncontrolled diabetes
  • Smoking
  • High cholesterol
  • High blood pressure
  • Genetic history

Diagnosing Renal Artery Disease:

Your symptoms and your risk factors will be considered when making a diagnosis. Tests may include:

  • A renal artery duplex ultrasound scan:This is a non-invasive test using sound waves to create images of your renal arteries, as well as measure the speed at which flows through the arteries.
  • A CTA (computed tomography arteriography) scan: This scan uses X-rays taken from various angles to create pictures of cross sections of your body. When contrast dye is used, the arteries can be visualized. These pictures, while not as detailed as a renal arteriogram, may be sufficient to make a diagnosis and only require an IV placed in the arm.
  • An MRA (magnetic resonance angiogram) scan: This is like an MRI (Magnetic Resonance Imaging scan). However, it uses radio waves (instead of X-rays or any form of radiation) and a magnetic field to take pictures of the blood vessels to take successive pictures of the blood vessels. A contrast fluid is sometimes used; however, it is different in that it is different than that used for the renal arteriogram and CTA. The advantage is that is does not have the potential negative side effects on the kidneys. However. Like the CTA, MRA uses computer techniques to make the blood vessels more visible.
  • Blood tests: Certain blood tests can identify substances in the blood either produced by the kidneys or are increasing when the kidneys are not working properly.
  • A renal arteriogram, also called an angiogram: This 20-40-minute procedure is performed in a special room in the hospital called a catheterization laboratory (cath lab) by an Interventional Radiologist and cath lab staff. This exam, involving X-rays, serves to identify narrowed or blocked renal arteries. After the procedure is explained to you and consent forms are signed, a small intravenous (IV) tube will be inserted into your arm, allowing IV fluids and medications to be administered. Through the IV, a mild sedative is given so you can relax for the procedure. Small sticky patches (electrodes) are on your chest to monitor your heart rate and rhythm. The area where a catheter will be inserted (either your groin or your arm) will be shaved and washed, and numbing medication will be applied as a local, topical anesthetic. Your body will be draped with sterile sheets. Next, a hollow tube will be placed at the point of access (groin or arm) through which your doctor can advance or remove guide wires and catheters to the arteries leading to your kidneys. A special X-ray contract dye will be pushed through the tube to allow your doctor to see and record images of the arteries leading to your kidney on an X-ray monitor. Once the doctor has finished the angiogram and other treatments or procedures (if any) are complete, you will go to a recovery area for monitoring. Four to six hours following the procedure, you will be asked to lie flat and not bend your leg or arm, depending on which approach your doctor used to insert the catheters. A vascular closure device may be used to seal the puncture site in your groin or arm.

Renal Artery Disease Treatments:

Treatment goals are to open up the blood flow to the kidneys. Treatment goes better when there is a significant change in life style afterwards. These treatments include:

  • Drug therapy: Your doctor may prescribe drugs to dilate (or expand) the arteries to increase the blood flow to your kidneys. If you have high blood pressure, drugs to lower blood pressure may be prescribed.
  • Surgical procedures: These two procedures — renal artery endarterectomy or renal artery bypass– are both surgical procedures in which patients may be hospitalized for at least a week.
    • Renal artery endarterectomy: In this surgical procedure, the surgeon exposes the renal artery through an incision. The plaque is physically removed.
    • Renal artery bypass: A similar procedure as the renal artery endarterectomy except that a bypass is made around the blocked artery rather than removing the plaque from the artery. A healthy segment of vein or artery from another part of the body is used to create a bypass (detour) so blood can flow around the clogged area.
  • Balloon Angioplasty,known as Percutaneous Translumenal Angioplasty, PTA : This procedure is similar to the renal arteriogram procedure described above. A catheter with a small balloon on the tip is directed to the area of plaque buildup in the renal artery. The balloon is then inflated to push the plaque against the artery wall to create a larger arterial opening. This improves the blood flow through the artery or, in other words, widens the “artery lumen.” The balloon is then deflated, after which the catheter with balloon attached is withdrawn from the body.
  • Stenting: In some cases, it is determined that the result of the balloon angioplasty alone will not provide sufficient blood flow through the arteries. In such instances, the interventional radiologist may place a stent (an expandable wire-mesh tube) in the artery to keep it from closing again (a condition called restenosis). The stent is a mesh-like tubular metal scaffold placed on a specially designed balloon catheter and then delivered to the diseased area in the same fashion as the PTA balloon catheter. For some patients, stinting is contraindicated because 1. they cannot take platelet inhibitors (anti-platelet) and-or anticoagulation therapy that may be needed, or 2. their renal artery disease in a location that prevents complete inflation of an angioplasty balloon.

What Happens After Procedure?

Some pain killers may be given before and after the procedure to help with being uncomfortable. Medication must be taken correctly to ensure a healthy recovery.