Bypass Oparation
Coronary artery bypass graft (CABG)
operation was first introduced by Dr. Favaloro in 1969. Since its introduction,
bypass operation has become the most completely studied operation in the
history of surgery. This operation has been shown to be highly effective in the
relief of severe angina and prolonging life. The operation is done to bring
additional blood supply to the areas of the heart previously deprived of blood.
This deprivation is due to the narrowing of the arteries supplying the muscle.
The area in the coronary artery that is narrowed or completely blocked is
bypassed by segments of veins taken from the legs. Coronary artery bypass graft
surgery is a very common and successful way of restoring health and vigor to
people with coronary artery disease. The blockage of the coronary arteries can
reduce the amount of blood reaching the muscle. This may lead to bouts of chest
pain called angina or to a heart attack. The operation will improve or remove
angina and will help you to live longer. The bypass grafts improve the blood
supply to the heart muscle, allowing it to function better and preventing
angina. This operation bypasses the narrowed areas in the coronary arteries to
allow blood to get to the heart muscle. The bypass is constructed from either
an artery from inside your chest or veins from your legs. Radial arteries (hard
artery) are now frequently used for constructing bypasses. Sometimes bypasses
are obtained from other aorta (the main artery leading from the heart) and the
coronary artery, whereas the internal mammary artery is usually left attached
to its inflow arterial supply and the end sewn to the coronary artery beyond
the narrowed part.
How does CABG help?
The improved blood flow resulting
from the operation should mean a better quality of life:
·
Less or no angina
·
Less need for GTN tablets/spray
·
You can be more active
·
It may also help you live longer as well as better.
How it is done?
Bypass operation is on open heart
surgery and it is done by using heart lung machine. An incision is given on the
sternum and after sternotomy (sawing and cutting the breastbone) the operation
is finally performed. The operation consists of construction of new pathways
(channels) between the aorta (main artery of human being) and the portions of
the coronary arteries beyond the narrowing or total obstruction. The new
channels (grafts) are harvested from the legs. A big leg vein called greater
saphenous vein is usually used for creating new channels. The sizes of this
vein comfortably match with the coronary arteries. Another method of operation
is to use the internal mammary artery graft which runs underneath the breast
bone. In this operation surgeons use arterial grafts (internal mammary artery)
from the chest instead of veins from the legs. If a patient requires more than
2 or 3 bypasses, surgeon simultaneously uses both internal mammary and venous
graft. It has been proved over years that arterial grafts are always better
than the leg vein grafts.
Is it rational to undergo bypass operation?
It is important to undergo CABG
(bypass operation) for two definite reasons –relief of disabling chest pain not
responding to optimal medical therapy and for the prolongation of life. As
regards prolonged survival in those with coronary artery disease there have
been several well documented large scale clinical trials showing that when the
left coronary artery is obstructed or when two or more important coronary
arteries are significantly narrowed then CABG provides longer survival than
medical treatment. This operation is associated with a very small 1-2% risk of
operative death. After operation 88% of patients survive for >5 years, 75%
for >10 years and 60% survive more than 15 years. The use of internal
mammary arteries as bypass channel has revolutionized the operative outlook of this operation. About 95% of internal mammary arteries remain patent even 10
years after the operation and closure of the mammary artery after this time is
uncommon. Usually left internal mammary artery is used but now-a-days right is
also frequently used. Currently available information’s indicate that the
internal mammary artery should be used almost routinely for bypassing left
coronary artery block. Both left and right coronary arteries can be used in
same patient. Leg veins are not very rewarding like arterial grafts because 50
to 60% of leg vein grafts remain patent after 10 years. Older age in itself is
not a contraindication to the bypass operation. Bypass operation can be
repeated twice or thrice on the same patient.
When to undergo the operation?
During last 28 years since coronary
artery bypass graft surgery was introduced, it has become clear that the
operation relieves angina pectoris and improves quality of life. Early CABG
surgery improves survival over policy of initial medical therapy. The benefits
are especially pronounced in patients with more extensive coronary artery
disease or ischaemia and in those who have clinical or angiographic features
indicating high or moderate risk.
Post operative course
Approximately 5-10 days after surgery
most patients recover well enough to leave hospital and most are able to return
to work after two weeks rest at home. During the 1st 6 to 8 weeks of
operation, patients commonly have a poor appetite, insomnia, emotional, depression,
visual or memory or intellectual deficits, loss of sexual ability, lack of
desire to return to work. These are all transient phenomena and patients
recover completely from these symptoms. Coronary artery bypass graft operation
has favorable effects on symptoms and useful life expectancy in most of the
patients. However, it does not cure the disease and in most patients at some
point, usually many years after operation the symptoms recur. In most of the
patients after operation the patients become pain free; in others the pain,
although still present, is milder and more manageable. Patient should continue
aspirin, dipyridamole or ticlopidine type of medicines after surgery. These
medicines prevent recurrence of disease in the bypass channels.
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