Angioplasty and Vascular Stenting
What are Angioplasty and Vascular Stenting?
Angioplasty with or without vascular stenting is a minimally invasive procedure performed to improve blood flow in the body's arteries and veins.
In an angioplasty procedure, imaging techniques are used to guide a balloon-tipped catheter, a long, thin plastic tube, into an artery or vein and advance it to where the vessel is narrow or blocked. The balloon is then inflated to open the vessel, deflated and removed.
During angioplasty, a small wire mesh tube called a stent may be permanently placed in the newly opened artery or vein to help it remain open. There are two types of stents: bare stents (wire mesh) and covered stents (also commonly called stent grafts).
Some common uses of the procedures
Angioplasty with or without vascular stenting is commonly used to treat conditions that involve a narrowing or blockage of arteries or veins throughout the body, including:
· narrowing of large arteries (aorta and its branches) due to atherosclerosis, or hardening of the arteries, a gradual process in which cholesterol and other fatty deposits, called plaques, build up on the artery walls.
· peripheral artery disease (PAD), a narrowing of the arteries in the legs or arms. In patients with PAD, angioplasty alone or angioplasty with stenting may be used to open up a blocked artery in the pelvis, leg or arm.
· renal vascular hypertension, high blood pressure caused by a narrowing of the kidney arteries. Angioplasty with stenting is a commonly used method to open one or both of the arteries that supply blood to the kidneys. Treating renal arterial narrowing is also performed in some patients to protect or improve the kidney function.
· carotid artery stenosis, a narrowing of the neck arteries supplying blood to the brain.
· coronary artery disease, a narrowing of the coronary arteries that carry blood and oxygen to the heart muscle.
· venous narrowings involving the central veins (in the chest, abdomen or pelvis). In some cases, stenting of the narrowed vein is also needed.
· narrowing in dialysis fistula or grafts. When there is decreased flow in the graft or fistula so that is not adequate for dialysis, angioplasty is generally the first line of treatment. Stenting or stent grafting may also be needed in some cases.
Procedure
Image-guided, minimally invasive procedures such as angioplasty and vascular stenting should only be performed by a specially trained interventional radiologist in an interventional radiology suite or occasionally in the operating room.
This procedure is often done on an outpatient basis. However, some patients may require admission following the procedure. Please consult with your physician as to whether or not you will be admitted.
You will be positioned on the examining table.
You may be connected to monitors that track your heart rate, blood pressure and pulse during the procedure.
A nurse or technologist will insert an intravenous (IV) line into a vein in your hand or arm so that sedative medication can be given intravenously. Moderate sedation may be used. As an alternative, you may receive general anesthesia.
The area of your body where the catheter is to be inserted will be shaved, sterilized and covered with a surgical drape.
Your physician will numb the area with a local anesthetic.
A very small skin incision is made at the site.
A sheath is first inserted into the artery, or vein, if the narrowed blood vessel is a vein.
Guided by x-rays, the catheter is then inserted through the skin and maneuvered through the artery until it reaches the site of the blockage. Once the catheter is in place, contrast material will be injected into the artery and an angiogram will be taken of the blocked artery to help identify the site of the blockage.
With x-ray guidance, a guide wire will then be moved to the site, followed by the balloon-tipped catheter. Once it reaches the blockage, the balloon will be inflated for a short period of time. The same site may be repeatedly treated or the balloon may be moved to other sites.
Additional x-rays will be taken to determine how much the blood flow has improved. When your physician is satisfied that the artery has been opened enough, the balloon catheter, the guide wire and catheter will be removed.
Many angioplasty procedures also include the placement of a stent, a small, flexible tube made of plastic or wire mesh to support the damaged artery walls. Stents can be self-expandable (opens up itself upon deployment) or balloon expandable (balloon needed to open the stent). Balloon expandable stents are typically placed over a balloon-tipped catheter so that when the balloon is expanded, it pushes the stent in place against the artery wall. When the balloon is deflated and removed, the stent remains permanently in place, acting like a scaffold for the artery. Self-expandable stents are easy to deploy, but may require additional angioplasty with balloon to obtain satisfactory dilation (opening) of the diseased vessel. Covered stents or stent-grafts have additional advantages over bare stents and are becoming more commonly used.
Drug-coated (also called drug-eluting) stents have recently been approved for clinical use by the U.S. Food and Drug Administration (FDA). These stents are coated with a medication that is slowly released to help keep the blood vessel from re-narrowing, a condition called restenosis.
At the end of the procedure, the catheter will be removed and pressure will be applied to stop any bleeding. The opening in the skin is then covered with a dressing. No sutures are needed.
You may need to lie in bed with your legs straight for several hours. In some cases, your physician may use a device that seals the small hole in the artery, called a "closure device", which will allow you to move around more quickly.
When the procedure is completed, you will be moved to a recovery room or to a hospital room.
Your intravenous line will be removed.
The length of the procedure varies depending on the time spent evaluating the vascular system prior to any therapy, as well as the complexity of the treatment.
Benefits
· Compared to surgical interventions such as bypass surgery, balloon angioplasty and stent placement are much lessinvasive and relatively low-risk, low-cost procedures.
· These procedures are performed using local anesthesia; no general anesthetic is required in the majority of patients.
· No surgical incision is needed—only a small nick in the skin that does not have to be stitched closed.
· You will be able to return to your normal activities shortly after the procedure.
Risks
· Major complications following angioplasty are uncommon. However, inserting the catheter can lead to injury of the artery. The procedure also poses a very small risk of blood clots or tearing the artery.
· When angioplasty is performed alone, blockages can recur, although most of these arteries can be opened again successfully. This can also occur when a stent is placed in the artery at the time of the angioplasty.
· Heavy bleeding from the catheter insertion site may require special medication or a blood transfusion.
· There is a risk of stroke when angioplasty and/or stenting are performed on the carotid artery.
· A relatively rare complication associated with balloon angioplasty is abrupt vessel closure, or occlusion. This blockage in the area treated by the balloon angioplasty typically occurs within 24 hours of the procedure. If it happens, treatment with medication into the artery to dissolve clots followed by angioplasty or stenting may be appropriate. In some cases, emergency bypass surgery may be needed.
· Other rare complications include heart attack and sudden cardiac death.
· Any procedure where the skin is penetrated carries a risk of infection.
· There is a very slight risk of an allergic reaction if contrast material is injected.
· Any procedure that involves placement of a catheter inside a blood vessel carries certain risks. These risks include damage to the blood vessel, bruising or bleeding at the puncture site, and infection.
· Contrast material used during these procedures may cause renal failure, a decrease in kidney function, particularly if there is already some degree of decreased kidney function. Your physician generally checks your renal function before this procedure in order to lower this risk