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ARTICOLI E DOCUMENTI MEDICI
HEART VALVE SURGERY
Valves are the doorways of the heart. When open, valves only
permit blood to flow in one direction.
When closed, they form a strong seal both between the different
chambers of the heart and between the chambers and the blood
vessels. There are two types of damaged valves:
(1) leaky or regurgitant valves that allow reverse blood flow,
and
(2) stenotic valves or valves that do not open fully, restricting
the blood flow. Valve damage has many possible causes.
Stenotic valves are often a natural result of aging. An infection
can scar or rupture a valve. A heart attack can create a leaking
valve. And congenital defects can cause any of the above.
Depending on the extent and location of the damage, valves can
either be repaired or replaced. Aortic valves are the most frequently
replaced valve. The aortic valve controls the flow of blood
from the left ventricle of the heart to the aorta (the main
artery of the body).
Mitral valves are both repaired and replaced, depending on the
extent of damage.
The mitral valve controls the flow of blood from the left atrium
to the left ventricle.
Two types of valves are used for replacement. Tissue valves
are valves that come from an animal donor. The most common sources
of a tissue valves are the valve leaflets of pigs.
Human organ-donor valves (homografts) can be used, but are uncommon.
The advantage of tissue valves is that they do not require blood
thinners. (Blood thinners, or anti-coagulation drugs, are medicines
that help prevent the blood clotting caused by the presence
of artificial material in the bloodstream.)
Until recently tissue valves tended to wear out after 10-15
years, limiting their use. Recent data shows that bioprosthesis
valves are lasting at least 14 years in patients over 70 years
of age.
Bioprosthesis valves mix nature with modern technology. The
leaflets are made from the tissue of a pig's valve, while the
strut, or structure, relies on such man-made materials as polyester
and plastic. Newer bioprosthetic valves are now being developed
which do not have any strut.
These may have improved hemodynamics and last longer than stented
bioprostheses
The second type of valve (mechanical) relies solely on modern
technologies such as space-age ceramics -
- the same material used in the tiles on the space shuttle.
These mechanical valves have an extremely long life-span, but
require the use of blood thinners. We use mechanical valves
for our patients who are under 65 years old, or who already
have another condition that requires the use of blood thinners.
Artificial Heart Valves
CONGENITAL HEART DISEASE TREATMENTS
Many children with congenital heart and blood vessel defects
may need medical treatment such as diuretics, digoxin or other
drugs. Diuretics promote the excretion of water and salts by
increasing the rate that urine forms. Digoxin makes the contraction
of the heart muscle stronger, slows the rate of heartbeats and
helps remove extra fluid from body tissues. Some children may
need surgery.
What surgical procedures are used?
· Arterial switch
— A surgical procedure in which the major arteries are
switched in babies with transposition of the great arteries.
The aorta is connected to the left ventricle, which pumps oxygen-rich
(red) blood to the body. The pulmonary artery is connected to
the right ventricle , which pumps venous (bluish) blood to the
lungs. This arterial switch procedure may be done in the first
few weeks after birth or, depending on various factors, slightly
later. If there's a large ventricular septal defect or other
defects related to the transposition, the repair gets more complicated.
Then other surgical procedures may be needed. ·
Balloon atrial septostomy
— A special procedure used during heart catheterization
to improve the body’s oxygen supply in babies with transposition
of the great arteries. It enlarges the atrial opening and helps
the baby by reducing the cyanosis (blueness).
· Balloon valvuloplasty
— A procedure in which a special catheter (a tube introduced
into a blood vessel and threaded to the heart) containing a
deflated balloon is inserted into the opening of a narrowed
heart valve. When the balloon is inflated, the valve is stretched
open; then the balloon is removed. The procedure is used with
favorable results to improve blood flow in pulmonary stenosis
. It is also used in some cases of aortic stenosis, where the
long-term results are still being studied.
Damus-Kaye-Stansel procedure
— A surgical technique used to repair a congenital transposition
of the great arteries of the heart by dividing (cutting) the
pulmonary artery in two, and attaching the closest (proximal)
section to the ascending aorta and connecting the farthest (distal)
section to the right ventricle .
Fontan procedure or operation
— A surgical procedure in which the right atrium is connected
to the pulmonary artery either directly or with a conduit. This
allows blood to bypass an incomplete or underdeveloped right
ventricle , as in tricuspid atresia and pulmonary atresia .
The atrial defect is also closed to relieve cyanosis (blueness).
Pulmonary artery banding
— A procedure in which a surgeon places a band around
the pulmonary artery to narrow it and reduce the blood flow
and high pressure in the lungs. This is done to relieve such
defects as ventricular septal defect, atrioventricular canal
defect, and tricuspid atresia . When the child is older, doctors
can remove the band and fix the defect with open heart surgery.
Ross procedure
— A procedure in which a person’s diseased or abnormal
aortic valve is replaced with the patient’s own pulmonary
valve (pulmonary autograft). A homograft valve (valve from a
human donor) is then placed where the pulmonary valve was.
Shunt or shunting procedure
— The operation of forming a passage between blood vessels
to divert blood from one part of the body to another. It is
used to reduce the cyanosis (blueness) in infants with severe
tetralogy of Fallot and those with tricuspid atresia or pulmonary
atresia . ·
Venous switch or intra-atrial baffle
— A procedure that creates a tunnel inside the atria to
help correct transposition of the great arteries. It redirects
oxygen-rich (red) blood to the right ventricle and aorta , and
redirects venous (bluish) blood to the left ventricle and pulmonary
artery . In the Mustard procedure, the intra-atrial baffle is
made of tissue from the pericardium . In the Senning procedure,
the intra-atrial baffle is made of flaps from the atrial wall.
HEART TRANSPLANTS
When does a person need a heart transplant?
Sometimes the heart is irreversibly damaged by long-lasting
heart disease or viral infection of the heart. Adults with long-term
heart failure that doesn't respond to all available treatment
may be candidates for heart (cardiac) transplants. People with
various forms of cardiomyopathy (acute or chronic disease of
the heart muscle) are also possible heart transplant candidates.
When the heart can no longer work adequately and a person is
at risk of dying, a heart transplant may be indicated.
Heart transplantation is the removal of a diseased heart and
its replacement with a healthy human heart How many people need
and receive heart transplants? There were 2,361 heart transplants
performed in the United States in 1995 and 2,345 in 1996.
Each year about 16,000 Americans age 55 or younger could benefit
from a heart transplant.
This figure rises to about 40,000 at age 65 or below.
In the United States, 76.5 percent of heart transplant patients
are male; 85 percent are white; 52 percent are age 50–64
and 22 percent are age 35–49.
The one-year survival rate is 83 percent; the two-year survival
rate is 78.9 percent; the three-year survival rate is 75.4;
and the four-year survival rate is 71.7.
BATISTA HEART FAILURE PROCEDURE
What is the Batista heart failure procedure?
The Batista heart failure procedure is a potential alternative
to a heart transplant. It was developed by Brazilian surgeon
Dr. Randas J. V. Batista, primarily as a treatment for heart
failure. Today a small number of surgeons in the United States
and Europe as well as here at St Vincent's are performing
it and evaluating its effectiveness. It must be emphasized
that this is still an experimental procedure. When is it used?
The Batista procedure is used for patients whose heart muscles
have been stretched or weakened by disease, such as infection
or inflammation which have led to congestive heart failure.
(Weakened heart muscle that results from heartattack does
not seem to respond as well.) Because of their weakened condition,
these hearts can’t pump enough blood to sustain themselves
and the body.
In the Batista procedure a triangular or elliptical piece
of living heart tissue about the size of a golf ball is sliced
from the left ventricle . Then the heart is stitched back
together. By removing part of the left ventricle (the heart’s
main pumping chamber), the heart’s chamber is made smaller
and it can contract more effectively to pump more blood.
LEFT VENTRICULAR ASSIST DEVICE
What is a left ventricular assist device (LVAD)?
Left ventricular assist device (L.V.A.D.) is a mechanical
pump-type device that is surgically implanted. It helps maintain
the pumping ability of a heart that is unable to effectively
function on its own. This device is sometimes referred to
as a "bridge to transplant." People awaiting a heart
transplant often have to wait for a long time before a suitable
heart becomes available. During this wait, the patient's already
weakened heart may deteriorate and become unable to pump enough
blood to sustain life. An LVAD can assist the weakened heart
and "buy time" for the patient.How does an LVAD
work?
A typical type of LVAD will have a tube going into the left
ventricle that pulls blood from the ventricle into a pump.
The pump then sends blood into the aorta (the large blood
vessel leaving the left ventricle). This effectively "bypasses"
the weakened ventricle. The pump is placed in the upper part
of the abdomen. Another tube attached to the pump is brought
out of the wall of the abdomen to the outside of the body
and attached to the control system for the pump. LVADsare
typically used for weeks to months.
POSTOPERATIVE CARE
It is normal in the CCA (Critical Care) that your nurse frequently
checks your vital signs and your condition including measuring
your urine output, helping remove secretions from your mouth
with a suction catheter, helping you turn,cough, breathe deeply,
or draw blood samples.
Communication
While the breathing tube is in your mouth you will be unable
to speak. The staff and your family should communicate with
you by asking "yes" and "no" questions
so it will be easier for you to answer.
Pain Management Your doctor will order pain control for you
after surgery. Your pain medication will be given to you through
your IV the first few days after surgery, then will be given
to you in pill form after that. It is normal to feel sleepy
the first 24 hours after surgery.
Activity You will be helped to sit on the side of your bed
the first day after surgery, and will sit in the chair on
either the first or second day after your surgery. Your activity
will be gradually increased every day.
Coughing and Deep Breathing Exercises Once the breathing
tube is removed from your mouth, it is important to perform
coughing and deep breathing exercises to expand your lungs
and prevent pneumonia. You will be instructed on these exercises
prior to surgery. Your nurses will assist you while you are
in the CCA to perform these exercises. You should do ten deep
breaths every hour you are awake. You do not need to do all
the breaths consecutively. Take several deep breaths, then
rest. You should continue these exercises when you are transferred
to the telemetry floor (Cameron Wing 16 or Level Going Back
Upstairs After Surgery Usually one to two days after surgery
your IV lines and tubes have been removed and you are ready
to be transferred to a telemetry unit where you will be able
to increase your activity while still being monitored. We
will advance your activity with the help of the physiotherapist
and have you go up and down a flight of stairs prior to going
home.
It is vital to keep your lungs well expanded after surgery.
You may help to do this by using your Incentive Spirometer
and by doing coughing and deep breathing exercises every hour,
five to ten times.
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