| Vascutek
Patient Education |
|
| Vascular
Anatomy & Vascular
Surgery |
|
A Patient’s guide |
We
hope this information
will help you understand
more about your vascular
system and your prosthesis.
Hundreds of thousands
of men and women like
you, of all ages and
from all walks of life,
have prostheses and
continue to lead full,
enjoyable and productive
lives. |
This
information has been
compiled by a Consultant
Vascular Surgeon to
provide helpful background
knowledge to patients
who receive a vascular
prosthesis. It is intended
to supplement information
given by the patient's
own medical/surgical
team and is not a replacement
for such information. |
| Please
consult your General Practitioner
or Surgeon if there is
anything you are unsure
of. |
|
| Introduction |
| A
vascular prosthesis is
a man-made tube that replaces
or bypasses part of a
blood vessel, most commonly
an artery. This booklet
has been specially prepared
to help you understand
your vascular prosthesis
and what it will do for
you. |
| The
successful development
of vascular prostheses
has been likened to a
modern miracle and has
generated great excitement
over the years. The first
devices were developed
in the 1960's. Since then,
great progress has been
made in improving the
materials used and today's
prostheses are vastly
superior to the original
versions. |
Originally
the placement of a vascular
prosthesis was considered
to be experimental,
but, with the passage
of time, vascular prostheses
have become commonplace
and hundreds of thousands
of people have been
successfully treated.
Modern vascular prostheses
are widely accepted
as being dependable
and reliable - they
are a marvellous testimonial
to the scientists who
developed the materials
used to make them. |
As
you read through the
text, you'll learn how
your vascular system
works, the function
of your prosthesis and
answers to many of your
questions. For any information
not covered here, especially
questions of a medical
nature, please consult
your General Practitioner
or Surgeon. Between
them, they will know
your condition best
of all and will want
to know if anything
is puzzling you. |
| If
you wish to download a
pdf version for off-line
viewing, click here. |
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| What
is the vascular system? |
| First,
let's take a look at the
vascular system and how
it works. |
All
parts of the body require
a supply of blood. Blood
carries oxygen and nourishment
and has many other important
functions that allow
your body to work properly.
Blood is distributed
around the body by the
vascular system which
consists of the heart,
arteries and veins.
The heart is a highly
efficient pump, made
of special muscle which
pumps blood into the
arteries. These are
tubes that carry blood
to all parts of the
body. The arteries branch
and become progressively
smaller until they eventually
become microscopic capillaries.
It's easy for oxygen
and nourishment to leave
the blood in the capillaries
and enter the tissues
and organs. After blood
has passed through the
capillaries, it enters
the veins that join
together and become
progressively larger
as they carry blood
back to the heart. The
heart then pumps the
blood through the lungs
to pick up oxygen before
pumping it again into
the arteries, so starting
the whole process again. |
| Blood
leaving the heart in the
arteries is rich in oxygen
which is removed by the
tissues. Blood returning
to it in the veins has
been virtually depleted
of oxygen and has to be
revitalised by passage
through the lungs. |
The
drawing below shows
how the heart, arteries,
capillaries, veins and
lungs work together
to provide a highly
efficient system that
circulates blood around
the body. Normally,
your heart will beat
more than 100,000 times
every day (70 beats
per minute), thrusting
1500 gallons of blood
on a total journey of
approximately 12,000
miles through your vascular
system's arteries and
veins. This incredible
organ completes about
2.6 billion cycles in
an average lifetime.
Your vascular system
contains an average
of eight pints of blood
that is regularly being
renewed by new cells. |
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The
vascular system
carries the blood
in a closed system
from
the heart, through
organs and tissues
and then back to
the heart where
the process starts
again. |
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As
you can see in the diagram
above, the vascular
system carries the blood
in a closed system from
the heart, through organs
and tissues and then
back to the heart where
the process starts again.
When blood leaves the
heart for the body,
it contains a rich supply
of oxygen that is removed
by the tissues. When
it returns to the heart,
it has been virtually
depleted of oxygen and
has to be revitalised
by passage through the
lungs. |
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| What
goes wrong with the vascular
system? |
Although
all arteries become
more rigid with age,
some people develop
the disease "atherosclerosis"
or "hardening of
the arteries".
The term atherosclerosis
depicts what the affected
arteries look like -
they are narrowed by
deposits of material
that consists of hard
(sclerosis) and sludgy
(atheroma, from the
Greek for porridge)
components. |
The
mechanisms by which
atherosclerosis develops
are not known, but we
do know that some people
are prone to developing
it. There may be a genetic
predisposition in these
people. We also know
other factors that can
result in atherosclerosis.
Among these, smoking
is the worst culprit,
along with high blood
pressure, diabetes and
high cholesterol levels. |
Atherosclerosis
results in the narrowing
of blood vessels and
can eventually block
them. These narrowings
and blockages reduce
the amount of blood
that can pass through
the arteries into the
tissues and organs of
the body. The affected
parts are then unable
to work efficiently
and, if called upon
to do extra work, may
result in symptoms.
A common example is
cramp-like pain in the
legs when walking. The
narrowed arteries of
the legs are unable
to provide enough blood
and oxygen for the muscles
to work properly during
exercise. The muscles
therefore start to hurt.
At rest, however, less
oxygen is required and
there is enough blood
supply for the muscles
to work normally. This
is called intermittent
claudication. The equivalent
process in the heart
is called angina. |
A
different problem with
the vascular system
is caused by the weakening
of the wall in the artery.
This results in the
artery increasing in
size, resulting in an
aneurysm. Aneurysms
may rupture when they
reach a certain size
so it is recommended
that they are repaired. |
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| How
can atherosclerosis be
treated? |
It
is important to control
the factors that we
know will cause atherosclerosis.
There is little we can
do about our genetic
predisposition. The
most important thing
to do is not to smoke.
Looking for and treating
diabetes, high blood
pressure and a high
cholesterol level is
also very important.
With treatment, atherosclerosis
may stop getting worse
and may even improve
as long as you don't
smoke. |
Many
patients benefit from
taking aspirin regularly
and there are effective
medications for angina,
high blood pressure,
high cholesterol and
diabetes. Take advice
from your doctor about
taking any medication. |
Sensible
exercise is very beneficial,
although you shouldn't
exercise beyond "the
pain barrier".
If it hurts, you should
stop.
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| These
measures are all that
many patients require
as treatment for their
atherosclerosis. In a
small proportion however,
these measures are not
enough and some other
form of treatment has
to be considered. It is
your General Practitioner,
medical specialist or
surgeon who will help
you decide if you are
one of the people who
need additional treatment. |
If
you do need additional
treatment, an important
step in most cases is
an "angiogram".
This is an X-ray test
that involves injecting
dye into your arteries
through a needle in
your groin or arm. The
angiogram gives a "road
map" of your arteries
and shows exactly where
the narrowing and blockages
causing your symptoms
are. Some narrowing
and blockages can be
widened with a balloon
inserted into your arteries
through a needle. The
balloon is placed across
the narrowing and is
then blown-up –
This is called an angioplasty. |
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Angioplasty
- Widening a blockage
in an artery using
a balloon. |
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In other narrowing and
blockages which are not
suitable for angioplasty
the treatment is then
bypass surgery. |
A
vascular bypass can
be thought of as a dual
carriageway built around
a congested town. The
congested town is your
narrowed or blocked
artery while the dual
carriageway is the bypass
itself. The narrowed
or blocked artery is
not generally removed
and the bypass is joined
onto the side of the
healthy artery above
and below the affected
area. |
| The
diagram below shows how
this is done. |
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(a)
The blood
flow is restricted
through the
artery. |
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(b)
A bypass is
sutured into
place above
and below
the affected
area and normal
blood flow
is resumed. |
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The choice of material
for the bypass depends
on the exact site in
your body that needs
a bypass. A prosthesis
(artificial bypass)
is almost always chosen
for bypasses from the
abdomen to the legs
and to repair aneurysms.
In these positions,
a prosthesis can be
expected to work well
for many years. Bypasses
from the groin to sites
further down the leg
are often made with
your own vein that can
be used as a "spare
part". The further
down your leg your bypass
has to go, the more
likely it is that your
surgeon will try to
use your own vein as
this is the best material
to use in these circumstances.
Some bypasses in the
leg work just as well
with a prosthesis, however,
and in these cases your
surgeon will decide
which is best for you.
If you have no available
vein in your leg because
of previous bypass surgery
or because of varicose
veins, your surgeon
may choose to use a
prosthesis instead.
Bypasses made in the
arm often use vein "borrowed"
from your leg, but some
made around the shoulder
and in the neck will
use a prosthesis as
first choice.
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| How
vascular prostheses work |
A
prosthesis is medical
science's substitute
for your body's natural
artery. It works in
a similar way to the
one with which you were
born. It provides a
tubular bypass for arteries
that have become narrow
or blocked due to disease
processes. |
Vascular
prostheses are sophisticated
materials made into
tubes of variable length,
shape and diameter.
Every component is made
of the highest quality
materials and receives
a thorough visual and
functional inspection.
Each component and completed
device is tested during
every stage of production
and meticulously manufactured
using advanced knitting,
weaving or ePTFE technologies.
Sterility is guaranteed
and there are no risks
of passing on diseases
with the use of a prosthesis. |
The
vascular prosthesis
has inbuilt reserves
of strength and stability,
far above that of the
natural artery. It is
designed to be a permanent
part of your vascular
system whose function
is affected more by
other factors, such
as age and disease,
than by material from
which the prosthesis
is made. |
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| Future
Outlook |
|
Bypass Longevity
|
There
is a possibility that
a bypass may not work
forever. This is due
to a number of factors
such as how severe the
atherosclerosis was
in the first place,
how quickly it progresses
after the bypass operation,
whether you continue
to smoke and how well
the other factors which
influence atherosclerosis
are controlled. |
Bypasses
onto small arteries
in the legs (especially
below the knee) and
arms tend to last longer
if they were made with
your own vein as this
is a living material
that helps to keep the
blood flowing. |
If
a prosthesis should
block, it is highly
unlikely to be due to
prosthesis failure,
and is normally due
to the changes brought
about by advancing years
and further disease. |
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|
A Final Word |
| We
hope this information
will help you to understand
more about your vascular
system and your prosthesis.
Hundreds of thousands
of men and women of all
ages have prostheses and
continue to lead full,
enjoyable and productive
lives. |
| |
This
information was provided
as a service to medicine
by Vascutek,
a TERUMO Company.
© 2004 |
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