Angioplasty & Stenting
In this technique, the interventional radiologist inserts a very
small balloon attached to a thin tube (catheter) into a blood vessel
through a small nick in the skin. The catheter is threaded under
X-ray guidance to the site of the blocked artery. The balloon is
inflated to open the artery.
Stents are used to hold open
areas of arteries narrowed by artherosclerosis
Sometimes, a small metal scaffold / tube, called a stent, is inserted
to hold the blood vessel open. Between 70 percent and 90 percent
of angioplasty procedures use a stent, a hollow thin-walled wire
mesh tube, to keep the vessel open after widening it. Otherwise,
because arteriosclerosis is an ongoing disease, more plaques might
form and again limit blood flow. The stent is placed onto the balloon
and pressed firmly against the artery wall when inflating it. The
balloon then is deflated, leaving the stent in place to act as
How Should I Prepare For The Procedure?
Blood tests are routinely ordered; you may have blood drawn at the
hospital or a nearby clinic. You may be instructed to temporarily
stop taking certain medications such as those that thin the blood.
If you have diabetes it may be necessary to alter your insulin
dose on the day of angioplasty. The radiologist or a staff person
will ask you to sign a consent form that covers angioplasty. It
also will cover angiography, an x-ray study of the arteries involving
injection of contrast material.
Make sure that the radiologist knows if you have any allergies so
that special precautions can be taken. You will be asked not to eat
solid foods after midnight, but may take clear liquids. Smoking is
to be avoided the day before the procedure. Shortly before starting,
the area where the catheter is to be inserted in the groin or arm
will be shaved and washed with antibacterial soap to prevent infection.
In addition, you will have a tube placed into a vein in the arm or
hand to receive fluids and medicines as needed. The intravenous (IV)
line is used to give a sedative to help you relax and possibly make
you drowsy. It will stay in place until angioplasty is completed.
What Does The Equipment Look Like?
Angioplasty and stent placement are monitored as they take place
using high-resolution angiography equipment.
The equipment includes a balloon catheter, a small, thin angioplasty
catheter with a balloon at its tip, and, in some cases, a wire mesh
stent that is collapsed when passed into the artery. Stents come
in varying sizes so that in each case it matches the size of the
How Does The Procedure Work?
Inflating a baloon at a narrow
location within an artery
Angioplasty uses an inflatable balloon that is passed to the target
vessel and inflated. When plaque is narrowing the artery and limiting
the amount of blood that can get through, the inflated balloon
will press it against the side of the artery and stretch the artery
wall. The result is that the vessel is restored to its initial
size and thus allows more blood and oxygen to pass to the body
tissues it normally supplies. Occasionally the plaque will not
remain against the inner lining of the artery but goes back to
its former position after the balloon is deflated. Another possibility
is that a small amount of plaque may continue to block the flow
In these cases the radiologist may place a stent that is expanded
at the site of plaque. The muscle tissue in the vessel wall holds
the stent in place. In time, a layer of cells forms over the stent,
which in effect becomes a part of the vessel. In some cases the size
of the diseased artery and the site of blockage make a stent especially
useful. A stent also may be placed to keep an artery open if the
inflated balloon has torn or damaged it. Some modern stents are covered
with a drug that helps keep the artery open; they seem to improve
the long-term success rate.
How Is The Procedure Performed?
The first step is to set up an intravenous line and use it to give
a sedative. Then a local anesthetic is injected into the skin where
the catheter is to be inserted, usually in the groin. A very small
incision is made at this site, and a needle is placed in the femoral
artery in the groin. Next, a thin guidewire is placed through the
needle and the needle is exchanged over the guidewire for a catheter
that is then advanced up into the blocked artery. Occasionally
access is gained instead through a large artery in the upper arm.
The catheter is guided into the diseased segment of artery while
being monitored on a TV screen that shows the artery and the catheter.
A small amount of contrast material is injected to show the exact
location of the narrowing. The balloon-tip catheter, which is thinner,
is then inserted through the guide catheter. When its tip reaches
the narrowed part of the artery, the balloon is inflated for about
30 seconds and then deflated. Finally the balloon-tip catheter
is removed and angiography is repeated to make sure that blood
flow has improved. This entire process usually takes between one
to two hours.
Depending on the result of angioplasty, the site of narrowing, and
the physician's judgment, one of two types of stents may be placed.
One type is collapsed until very small in diameter and placed over
a balloon-tip catheter. Inflating the balloon expands the stent,
which locks in place to keep the artery open. The other type is secured
to a catheter by a sheath and self-expands when the sheath is removed.
Stent placement may be combined with angioplasty or it may serve
as an alternative procedure.
What Will I Experience During The Procedure?
When you receive a sedative through the IV line at the outset,
you will feel relaxed and sleepy but probably will stay awake throughout
the procedure. There should be no pain when the catheter first
is inserted into the groin artery, but you may notice slight pressure.
You may feel pain briefly in the part of your body closest to the
site of angioplasty when the balloon is inflated. This could be
back pain for renal angioplasty, and buttock pain when iliac angioplasty
is performed. After the procedure, the sheath will be removed
and pressure applied to the incision. Occasionally,
a collagen plug or suture may be used to assist in closure of the
incision. You will have to remain flat on your back and avoid moving
your leg or groin for about six hours to allow the incision to
heal. Most patients will be able to walk about 6 to 8 hours after
angioplasty. Most patients return home the same day, but some stay
in the hospital for a short time.
On returning home you should take it easy, avoid driving for 24
hours, and drink plenty of fluids. You should avoid strenuous exercise
for at least two days. It is best not to take a hot bath or shower
for the first 12 hours (sometimes longer if you had a suture or plug
placed), and to avoid smoking for 24 hours or longer. If bleeding
begins where the catheter was inserted, you should lie down, apply
pressure to the site, and have someone call your doctor right away.
Any change in color or a warm feeling in this area are also signs
that something is wrong, as is pain in the area where the balloon
was inflated or in the treated limb.
If a stent has been placed, you will be asked to take aspirin or
another anti-platelet drug indefinitely. MR imaging should be avoided
for a month unless a radiologist approves the study. Metal detectors
will not affect the stent.
Who Interprets The Results And How Do I Get Them?
The interventional radiologist judges the technical results of
angioplasty or stent placement by comparing the pre- and post-procedure
angiograms. If any narrowing remains, it should not exceed 30 percent
of the normal vessel diameter. The patient can be told of the technical
result as soon as the procedure is completed, though it is best
to wait until the sedative has worn off. The clinical outcome may
take longer to gauge. In the case of angioplasty of the arteries
to the kidneys, clinical benefit should be evident in one to four
weeks as a fall in blood pressure or the ability to reduce medication
to control the pressure.
What Are The Benefits Vs. Risks?
- Angioplasty, with or without stenting, is much less invasive
than open surgery, which in the case of blocked arteries
means a bypass operation. When angioplasty succeeds, major surgery
and the risks of general anesthesia are avoided. Overall cost is
much less, and the hospital stay is days or hours rather than weeks.
- Angioplasty and stent placement can be done using only local
anesthesia; you will not require a general anesthetic. No surgical
incision is needed—only a small nick in the skin that does
not have to be stitched closed. You can return to your normal activities
shortly after the procedure. Unlike bypass surgery, it is not necessary
to remove pieces of blood vessels from another part of the body.
- Although the results may not be as lasting as those of bypass
surgery, angioplasty can restore blood flow to vital tissues and
relieve symptoms for nearly the same length of time. Even after
bypass surgery, some of the new blood vessels occasionally become
- With angioplasty alone, an estimated one in ten blockages recur
in a few months, though most of these arteries can be successfully
dilated again. The chance of this happening is less when a stent
- The risk of serious effects from angioplasty is substantially
lower than open surgical procedures. There is a rare risk of vessel
rupture, which could require surgery or be life threatening.
- You may have an allergic reaction to the contrast material
injected for angiography. The risk of this happening is greater
in patients with kidney disease, diabetes or asthma and those who
have had a previous reaction to x-ray contrast material.
- Heavy bleeding from the catheter insertion site may call for
special medication or blood transfusion or even surgery to correct.
- There is a risk of stroke when angioplasty is performed on the
carotid artery and a stent is placed. This is because a blood clot
may form and travel to small brain vessels, where it stops blood
flow to brain tissue that requires a steady oxygen supply.
What Are The Limitations Of Angioplasty And Vascular Stenting?
- In a small percentage of cases, angioplasty—even with stent
placement—fails to increase blood flow bypass surgery is
necessary. Regardless of what artery is blocked, angioplasty does
not reverse the underlying disease—arteriosclerosis. The
procedure may have to be repeated if the same artery or another
one becomes blocked.
- Sixty to seventy percent of patients with renal hypertension
caused by arteriosclerosis have their blood pressure controlled
by angioplasty. By the time the procedure is done, many of these
patients have disease in small arteries within the kidneys that
cannot benefit from angioplasty. Renal artery angioplasty with
stenting causes complications in about 10 percent of patients,
though few of them are major. As in coronary angioplasty, the dilated
artery may again become narrowed, with hypertension the result.
- Angioplasty/stenting for arterial disease in the pelvis and legs
is less successful when there are narrowed arteries at more than
one level; when small vessels have to be dilated; and when not
enough blood gets through the treated segment of artery. Either
recurrent narrowing at the site of treatment or progressive arteriosclerosis
in an untreated artery may produce symptoms. Any patient with this
disease, no matter which arteries are affected, stands to benefit
from eating a proper diet, getting regular exercise, and controlling
- Placing a stent in the carotid artery that supplies blood to
the brain remains controversial because open surgery has proved
to be effective and safe. It certainly is helpful to patients who
cannot safely undergo surgery. Before long it may be possible to
use a filter device during stent placement that will keep clots
from passing to the brain, thereby lowering the risk of stroke.