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Intravascular Stents
It has been shown that the use of an expandable device (stent) at the site of percutaneous transluminal angioplasty achieves a greater patency rate (artery
remaining open) over time.
1. Balloon-expandable stents
Over the years the original Palmaz stent has under gone a facelift. No longer are these a bulky commodity but rather a thinstreamlines
stainless steel or Nitinol wire mesh.
The Palmaz-Schatz stent, illustrated at left, must be delivered to the obstructed site on a balloon catheter passed over a
wire. After the balloon is inflated, the stent expands. The balloon catheter is then removed leaving the stent in place to keep the artery open.
2. Self-expanding stents
Over the years the oringinal Wallstent has under faced stiff competition from
other new and improved devices These too are now stainless steel of Nitinol. There advantages are for use in tortuous blood vessels. A cover is removed from
the stent which allows it to open like an umbrella, sealing itself into place.
 The Wallstent, illustrated at right, is
delivered to the obstructed site by traversing over a wire. The outer protective covering is then retracted allowing the stent to self expand to keep the artery open . A balloon is then
passed over the wire to the affected site, where it is inflated for completion of the angioplasty procedure.
  A second type of self-expanding stent is the Smart Stent, made of Nitinol material. This has an
advantage of allowing a very small degree of shortening so as to allow the cardiologist to exactly place it in the proper position
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During the procedure the physician will insert a catheter (a long, thin flexible tube) into a blood vessel in your groin or arm. Contrast
, or dye, is then injected via these tubes to the vessel of concern while x-ray pictures are taken. This procedure can be performed on an outpatient basis. In preparation for your test, blood work will be
ordered one to two days before the scheduled date. The day of the procedure, you will be asked to arrive early to the lab and someone should be able to drive you home. Before the procedure, an
intravenous line will be started. You will remain awake throughout the procedure. It takes approximately 30-60 minutes to take the pictures. Once the procedure is complete, the catheter tube will be
removed and firm pressure will be applied to the entry site for approximately thirty minutes; also a large, tight pressure dressing
will be applied. You will return to your room or recovery area where you will need to lie flat in bed for 4 hours. When the dressing is removed, you will notice a
small bruise at the catheter insertion site, no larger than the size of a quarter. You may also feel a hard lump. It is normal to expect the bruise to become
slightly larger and darker the first few days you are home. They are the result of the body's normal healing process and should completely disappear in about two
weeks. If you become uncomfortable or are experiencing any discomfort, please call your doctor.
Balloon angioplasty is now the most common method used
for opening up a blocked artery in the heart, legs, kidneys, arms, or neck. The picture on the left shows a blocked Iliac artery. After the groin (arm) is washed with a sterile solution
a sheath is placed in the access site (groin, arm) to allow passage of the entire catheter system to the site of intervention. A thin floppy wire is passed into the sheath
system through the narrowed opening in the artery. A deflated balloon is passed over this wire to the obstructed area of concern. Under fluoroscopic (x-ray) guidance the
balloon is inflated. This causes the obstruction to be compressed into the walls of the artery
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This procedure is normally reserved for
treating areas that cannot be opened with balloon technology as it exists today. A laser catheter, illustrated at right, produces a high intensity light beam which vaporizes the
affected region without damaging the surrounding tissues. This then allows the passage of a balloon system to further open the obstruction. Balloon angioplasty /stent
procedure follows to ensure that the artery remains open To date many laser systems exist however only the Excimer laser is FDA approved.
Many arterial blockages may also contain a blood clot at the site of obstruction. Your physician may deem it necessary to instill a clot buster at that site either
before, during or after the interventional procedure. Various agents are available to your physician, including r-TPA (Alteplase) and r-PA (Retavase), TNKase and Urokinase. All of the available agents
function by dissolving clots in the vascular system. Because of the powerful nature of these medications it will be necessary for your physician to closely
monitor you for signs of excessive bleeding. This may require monitoring in the Intensive Care Unit overnight.
Implanting a stentgraft in
an Abdominal Aortic Aneurysm
