What is Coronary Angioplasty?
How is Angioplasty or PTCA performed?
How long does it take?
How safe is it?
Show me the results of an angioplasty
The heart is supplied by
three major coronary arteries and their branches (as
described in the cardiac cath section). Atherosclerosis
produces discrete (confined) or scattered areas of
blockage within a coronary artery. When the blockages
are large enough, they reduce blood supply to heart
muscle and produce angina. The tests used to make
the diagnosis of coronary artery disease and its medical
treatment have been discussed elsewhere. Some patients
with coronary artery disease may require surgery.
Many patients with serious disease or those who fail
on medical therapy are treated with a "needle
hole" or "percutaneous" (through the
skin) procedure that is performed in the cardiac cath
laboratory. Angioplasty is one of these procedures.
It was introduced to the world by Dr. Andreas Gruentzig
in the mid to late 1970's and is widely used today.
What is PTCA or Angioplasty?
Angioplasty is a technique used to dilate an area
of arterial blockage with the help of a catheter that
has an inflatable small sausage-shaped balloon at
Since the balloon catheter is introduced through the
skin of the groin, and sometimes the arm ( percutaneous
= through the skin), is placed within a blood vessel
(transluminal = in the channel or lumen of a blood
vessel) and is applied in the treatment of coronary
arteries, the technique is also called PTCA or Percutaneous
Transluminal Coronary Angioplasty.
opens the channel of diseased arterial segments (see
below), relieves the recurrence of chest pain, increases
the quality of life and reduces other complications
of the disease. Since it is performed through a little
needle hole in the groin (or sometimes the arm) it
is much less invasive than surgery and can be repeated
more often should the patient develop disease in the
same, or another, artery in the future.
How is PTCA
performed? Prior to performing PTCA, the
location and type of blockage plus the shape and size
the coronary arteries have to be defined. This helps
the cardiologist decide whether it is appropriate
to proceed with angioplasty or to consider other treatment
options such as stenting, atherectomy, medications
or surgery. Cardiac catheterization
(cath) is a specialized study of the heart during
which a catheter or thin hollow flexible tube is inserted
into the artery of the groin or arm. Under x-ray visualization,
the tip of the catheter is guided to the heart. Pressures
are measured and an x-ray angiogram (angio) or movie
of the heart and blood vessels is obtained while an
iodine- containing colorless "dye" or contrast
material is injected into the artery through a catheter.
The iodinated solution blocks the passage of x-rays
and causes the coronary arteries to be visualized
in the angios. In other words, coronary arteries are
not ordinarily visible on x-ray film. However, they
can be made temporarily seem by filling them with
a contrast solution that blocks x-ray.
As discussed in the cardiac
cath section, a sheath is introduced in the groin
(or occasionally in the arm). Through this sheath,
a long, flexible, soft plastic tube or guiding catheter
is advanced and the tip positioned into the opening
or mouth of the coronary artery. In the picture below,
the catheter tip is positioned in the mouth of the
left main coronary artery.
The tube measures 2 to 3 mm in diameter. The tip of
the catheter is directed or controlled when the cardiologist
gently advances and rotates the end of the catheter
that sits outside the patient.
Once the catheter tip is seated
within the opening of the coronary artery, x-ray movie
pictures are recorded during the injection of contrast
material or "dye."
After evaluating the x-ray movie
pictures, the cardiologist estimates the size of the
coronary artery and selects the type of balloon catheter
and wire that will be used during the case. Heparin
(a "blood thinner" or medicine used to prevent
the formation of clots) is given.
The guide wire which
is an extremely thin wire with a flexible tip is inserted
into through the catheter and into the coronary artery.
The tip of the wire is then guided across the blockage
and advanced beyond it (see animation, top-right).
The cardiologist controls the movement and direction
of the guide wire by gently manipulating the end that
sits outside the patient. This wire now serves as
a "guide" or rail over which the balloon
catheter can be delivered. The tip of the balloon
catheter is then passed over the guide wire and positioned
across the lesion or blockage.
A deflated sausage-shaped
balloon is located on the tip of the catheter shaft.
It is inflated by connecting it to a special handheld
syringe pump. A mixture of saline and contrast material
is used to inflate the balloon. The contrast material
helps to visualize the balloon when it is inflated.
The balloon catheter also has metallic markers (either
at the center or on either side of the balloon). This
helps the cardiologist know the location of the otherwise
Inflation is initially
carried out at a pressure of 1 to 2 times that of
the atmosphere and then sequential and gradually increased
to 8 - 12 and sometimes as high as 20 atmospheres,
depending upon the type of balloon that is used. The
handheld inflation syringe has markers that are used
to determine the pressure. The balloon is kept inflated
for 1/2 to 2 minutes and then deflated until the next
inflation is used. Intermittent inflation allows blood
flow through the artery during the time that the balloon
is deflated. A nitroglycerin solution may be injected
to prevent spasm of the artery.
As the balloon is inflated,
it compresses the atheroma and plaque that make up
the coronary blockage. The process is similar to sticking
a clump of a spongy plastic "dough" to the
inside wall of a plastic tube (with the help of a
super-type glue) to create a blockage that restricts
the flow of water. The "dough" is then compressed
with a balloon tipped catheter. During each inflation,
the "dough" is compressed or "squashed"
even more. This is continued until the opening of
the tube at that level of the blockage becomes closer
to the tube not covered with "dough." Unfortunately,
the obstruction material of atherosclerosis is composed
of soft fatty atheroma, firm plaque and a medium consistency
mixture of the two. These material resist expansion
by a balloon in different ways. Soft material is compressed
easily while firm matter compresses to a lesser degree
and may demonstrate cracks following expansion by
a balloon. That is why the opening created by a balloon
is not always round and smooth.
It is important to remember
that the balloon of angioplasty catheters is not made
of rubber used in toy balloons. Special material is
employed so that the catheter balloon inflates to
a predictable size at a given pressure. For example,
a particular brand of balloon will open up to a 2
mm diameter with 8 atmospheres of pressure and 2 1/4
mm at 16 atmospheres.
The picture on the
left shows the rounded unobstructed channel of a normal
coronary artery (cross-sectional view). The middle
picture shows that the channel (through which blood
flows) is significantly reduced by a blockage. The
diagram on the right shows an increased opening after
the blockage was dilated or opened up with balloon
The patient remains awake throughout the procedure
and mild sedation is used to ensure relaxation and
comfort. The deflated balloon and wire are withdrawn
when the cardiologist is satisfied with the results.
If the result is unsatisfactory, a second balloon
or even a stent may be considered. Final angiograms
or movie x-ray pictures are taken upon completion
of the case. The guiding catheter is then withdrawn.
The sheath is secured to
the groin with a suture and the patient is sent to
his or her room. The sheath is removed when the effect
of Heparin wears off. This is determined by obtaining
blood tests at specified intervals. Other medications
that prevent blood-clots may be used in some cases.
Pressure is applied to the groin with a clamp. Once
it is confirmed that there is no bleeding, a sandbag
or ice bag is placed over the groin.
After approximately 6 hours, the
patient is ambulated or allowed to walk with assistance
and is usually discharged the following morning. A
Band-Aid or small dressing is applied over the tiny
needle hole. Slight bruising around the site is not
In some labs, a sealant device
is applied in the cath lab after removal of the sheath.
For a description of the
equipment, preparation and experiences during the
procedure, please review the cardiac
cath section. It is not uncommon for patients
to experience chest discomfort while the balloon is
inflated. This usually resolves when the balloon is
deflated. Patients who are uncomfortable can be given
intravenous medication to alleviate this problem.
Results of balloon
The video on the left shows an 80% blockage in the
proximal portion of the left anterior descending coronary
artery (arrow). The video to its right shows no remaining
blockage after the patient was treated with balloon
How long does the procedure
take? It can take anywhere from 30 minutes
to a three hours to perform the entire case. The duration
is dependent upon the technical difficulty of the
case and the number of balloon catheters that have
to be employed.
How safe is the procedure?
In the hands of experienced cardiologists, and with
availability of modern day technology, it is estimated
that the risk of death is during an angioplasty procedure
is usually less than 1%, while the chance of requiring
emergency bypass surgery is around 2% or less. It
is a relatively safe procedure and is carried out
all over the world. An "out patient" or
an inpatient uncomplicated angioplasty usually require
23 hours or less of hospitalization after the procedure.
The risk of a other serious complication is estimated
to be less than 4 and probably around 1 to 2 per thousand,
and similar to that described for cardiac cath. The
risk of a heart attack and bleeding that requires
a blood transfusion is increased when compared to
cardiac cath. However, the risks are relatively low
and acceptable in most cases when one balances the
potential benefit against the expected risk (risk-benefit
The aggravation of kidney function (particularly
in diabetics and those with prior kidney disease)
is higher than that expected with cardiac cath because
of the larger amount of contrast material that is
usually required. In such cases, the cardiologist
takes extra precautions to prevent this possible complication.