Mar 15, 2017
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Renal artery stenting

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Renal Artery Angioplasty and Stenting

What are renovascular conditions?

• Renovascular conditions affect the blood vessels of your kidneys.

•  When the blood flow is normal through your kidneys, your kidneys rid your body of wastes. The kidneys filter these wastes into your bladder, and they exit your body through your urine.

• When your kidney blood vessels narrow or have a clot, your kidney is less able to do its work.

• Your physician may diagnose you with renal artery stenosis or renal vein thrombosis.

• Renal artery stenosis is the narrowing of kidney arteries. This condition causes high blood pressure and may eventually lead to kidney failure.

• Renal vein thrombosis means that you have a blood clot blocking a vein in your kidney. Blood clots in renal veins are uncommon and rarely affect the kidney, but they can sometimes travel to and lodge in arteries supplying your lungs, causing a dangerous condition called a pulmonary embolism.

What are the symptoms?

• You may not notice any symptoms. Renovascular conditions develop slowly and worsen over time.

• If you have high blood pressure, the first sign that you may have renal artery stenosis is that your high blood pressure may become worse or the medications that you take to control your high blood pressure may not be effective.

• Other signs of renal artery stenosis are a whooshing sound in your abdomen that your physician hears through a stethoscope, decreased kidney function, and congestive heart failure.

• In renal vein thrombosis, a clot in your vein may break free and block a healthy blood vessel. If this happens, symptoms may include:
  • Pain in the sides of your abdomen, legs, or thighs
  • Blood in your urine
  • Protein in your urine
  • A enlarged kidney that your physician can feel
  • Fever, nausea, or vomiting
  • High blood pressure
  • Sudden, severe swelling in your leg
  • Difficulty breathing

What causes renovascular conditions?

• Hardening of the arteries causes renal artery stenosis.

• Your arteries are normally smooth and unobstructed on the inside but, as you age, a sticky substance called plaque can build up in the walls of your arteries. Cholesterol, calcium, and fibrous tissue make up this plaque. As more plaque builds up, your arteries narrow and stiffen.

•  This is the process of atherosclerosis, or hardening of the arteries. Eventually, enough plaque builds up to interfere with blood flow in your renal arteries.

• Smoking, obesity, advanced age, high cholesterol, diabetes, and a family history of cardiovascular disease are factors that increase your chances for developing atherosclerosis.

• Nephrotic syndrome is the most common cause of a clot in the renal vein (renal vein thrombosis). Nephrotic syndrome is a condition in which large amounts of a protein called albumin leak into your urine.

• Other causes of renal vein thrombosis include injury to the vein, infection, and a tumor.

What tests will I need?

Your physician will recommend the following tests to help determine if you have renal artery stenosis:

• Ultrasound: allows your physician to see your blood vessels and organs using high-frequency sound waves. With ultrasound, your physician can locate clots inside your arteries and determine the size of your kidney

• Angiography:   locates a narrowing or blockage, measures blood flow, and removes blood for testing. In this test, your physician injects a contrast dye into your vessels and then takes x-rays. The structure inside of your vessels appears on the x-ray because x-rays cannot pass through the dye. This test finds the location and pattern of blockages in your kidney blood vessels

• Spiral computed tomography (CT) scan: creates detailed three-dimensional images from x-rays of slices of your body

• Magnetic resonance angiography (MRA: uses magnetic fields and radio waves to produce three-dimensional images of your arteries

• Radionuclide scanning:uses a radioactive substance and a special camera to analyze the blood flow through your kidney

 How are renovascular conditions treated?

Medication

• If your physician diagnoses renal artery stenosis, he or she may prescribe blood pressure medications.

Some medications may include:
 • Diuretics
 • Beta-blockers
 • Angiotensin-converting enzyme (ACE) inhibitors
 • Calcium channel blockers


Thrombolysis

• If you experience sudden blockage in your renal artery, your physician may recommend a procedure called thrombolysis.

• In thrombolysis, a vascular physician injects a clot-dissolving medication directly to a clot through a long, thin tube called a catheter.

• If your physician diagnoses renal vein thrombosis, he or she may give you anticoagulants. These medications decrease your blood's ability to clot. In critical cases of renal vein thrombosis, your physician may perform thrombolysis.

Angioplasty and stenting

• If your renal artery is partially or completely blocked, your physician may recommend a procedure called angioplasty and stenting.

•  To perform this procedure, your physician inserts a catheter through a small incision and guides it through your blood vessels to your renal artery.

• The catheter carries a tiny balloon that inflates and deflates, flattening the plaque against the walls of your artery.

• Next, your physician may insert a tiny metal-mesh tube called a stent in the artery to hold it open.

Surgery

• Two surgical procedures that your physician may use to treat renal artery stenosis are endarterectomy and surgical bypass.

• In a renal endarterectomy, a vascular surgeon removes the inner lining of your renal artery, which contains the plaque. This removes the plaque and leaves a smooth, wide-open artery.

• Bypass surgery creates a detour around the narrowed or blocked sections of your renal artery.

• To create this bypass, a vascular surgeon connects one of your veins or a tube made from man-made materials above and below the area that is blocked. This creates a new path for your blood to flow to your kidneys.

• The choice of the procedure that is best for your situation depends upon the extent and location of the blockages. 

What can I expect?

Your vascular surgeon will discuss the treatment options with you and decide on the treatment that is right for you.

Angioplasty and stenting

• Prior to your procedure, tests may be scheduled such as blood work, electrocardiogram (ECG), and chest x-ray. These may be done at a separate appointment, or the day of the procedure

• Angioplasty or stenting is commonly done as an outpatient procedure, although some patients are hospitalized (inpatients)

• You can wear whatever you like to the hospital. You will wear a hospital gown during the procedure.

• If you normally wear dentures, glasses or a hearing assist device, plan to wear them during the procedure to assist with communication.

• Your doctor or nurse will give you specific instructions about what you can and cannot eat or drink before the procedure.

• Ask your doctor what medications should be taken on the day of your test. You may be told to stop certain medications, such as Coumadin (warfarin, a blood thinner).

• If you have diabetes, ask your physician how to adjust your medications the day of your test.

• Tell your doctor and/or nurses if you are allergic to anything, especially iodine, shellfish, x-ray dye, penicillin-type medications, latex or rubber products (such as rubber gloves or balloons).

• You may or may not return home the day of your procedure. When you are able to return home, arrange for a companion to bring you home.

• Please bring a list of your medications (including over-the-counter) and dosages. When you arrive for your appointment, please tell your nurse if you are taking Coumadin (warfarin), Plavix (clopidogrel), diuretics (water pill) or insulin.

• You will be given a hospital gown to wear. A nurse will start an intravenous (IV) line in your arm so that medications and fluids can be administered during the procedure.

• You will lie on a special table and you will be able to watch your procedure  on the monitors.

• The nurse will clean your skin at the site where the catheter (narrow plastic tube) will be inserted (arm or groin). The catheter insertion site may be shaved.

• Sterile drapes are used to cover the site and help prevent infection. It is important that you keep your arms and hands down at your sides, under the sterile drapes.

• Electrodes (small, flat, sticky patches) will be placed on your chest. The electrodes are attached to an electrocardiograph monitor (ECG), which monitors your heart rate and rhythm.

• You will be given a mild sedative to relax you, but you will be awake and conscious during the entire procedure.

• In some cases, a catheter may be placed into your bladder during the procedure.

• The doctor will use a local anesthetic to numb the site. A plastic introducer sheath (a short, hollow tube through which the catheter is placed) is inserted in a blood vessel in your arm or groin. A catheter will be inserted through the sheath and threaded to the arteries of your heart. You may feel pressure as the introducer sheath or catheter are inserted, but you should not feel pain. Tell the nurse or doctor if you feel any pain.

Angiography is usually performed again at the beginning of the angioplasty procedure or sometimes the angioplasty procedure is performed at the time of the initial angiogram.

Please tell the doctor or nurses if you feel: 
• itching, tightness in the throat (allergic reaction)
• nausea
• chest discomfort
• any other symptoms

After the procedure:

• The catheters and sheath are removed.

• The incision will be closed with applied pressure, suture device or a "plug." A "plug" is a material which works with your body's natural healing processes to form a clot in the artery. You will need to lie flat and keep the leg straight for two to six hours to prevent bleeding (less time if a plug was used). Your head cannot be raised more than 30 degrees (2 pillows high). Do not try to sit or stand.

• A sterile dressing will be placed on the angio site to protect it from infection. The nurse will check your bandage regularly, but call your nurse if you think you are bleeding (have a wet, warm sensation) or if your toes begin to tingle or feel numb.

• You will need to drink plenty of liquids to clear the contrast material from your body. You may feel the need to urinate more frequently. This is normal. If you are on bed rest, you will need to use a bedpan or urinal.

• Your doctor will tell you if you are able to return home or will need to stay overnight. In either case, you will be monitored for several hours after the procedure.

• Treatment, including medications, diet and future procedures, will be discussed with you prior to going home. Care of the wound site, activity and follow-up care will also be discussed.