CORONARY BYPASS SURGERY
Attention: A text on instructions to patients regarding heart surgery is to come.
Coronary artery bypass surgery is a cardiac surgery performed to supply blocked arteries with atheroma plaques.
It consists in making vascular bridges over partial or total obstructions of the arteries of the heart, because bridges help us cross obstacles.
To better understand
To understand, we must review the functioning of the heart and its oxygenation.
A muscular pump
The heart is a muscular pump the size of your fist.
Located in the center of the chest, between the two lungs, it is the motor of circulation. It beats on average more than 100,000 times a day.
Oxygen is its fuel
Its normal functioning is closely linked to its oxygenation, which is brought to it by the blood.
The delivery of its precious fuel is provided by the coronary arteries. Any reduction in oxygen supply can have serious and sometimes irreversible effects on the heart.
Left and right coronaries
The two coronary arteries, the left and the right, are located directly on the heart.
The size of a nail
They are easily visible and accessible by the surgeon. They measure on average from 1 to 3 mm.
When the atherosclerotic coronary disease, or the disease of the arteries of the heart, progresses, the presence of atheroma plaques, or commonly called cholesterol plaques, narrows the arteries of the heart.
These plaques are the accumulation of fat and calcium. When these plaques become large enough to slow the flow of blood, the heart is out of oxygen and the symptoms of angina (or chest pain) during effort appear.
When the artery is very severely narrowed or even completely blocked, the blood can no longer pass, the heart muscle suffers and it is painful!
When this pain persists for 20 to 30 minutes, the heart may stop contracting in this area or even die.
The myocardial infarction
This portion of the dead heart is then replaced by a scar: it is a myocardial infarction. This scar can be compared to the very tough whitish fillet in a piece of meat.
A scar on a portion of the heart muscle may make the heart less efficient at pumping blood.
In order to treat angina or a stroke, it is necessary to restore good circulation in the arteries of the heart.
A surgery with a rich history
For more than half a century, coronary bypass surgery has been used to bypass a narrowed or obstructed coronary artery by putting another vessel on top of it.
We build bridges
As the name says, this surgery places bridges over the narrowed arteries. It is like building a bridge over a river.
Two types of bridges
There are two kinds of bridging, which depend on the conduct used to pass over the blockage.
• Venous bypasses
• Arterial bypasses
Coronary artery bypasses are done with sections of veins taken from the leg and then used to build a bridge over the narrowed heart artery.
The blood in the leg that used these veins to return to the heart borrows other veins close by to continue their journey to the heart.
Arterial bypasses are made with sections of arteries.
The most commonly used artery is the left internal mammary artery, which is attached to the left inner side of the thorax below the breast.
The blood that used the artery is redirected to other arteries without any consequence.
Number of bypasses
The number of bypasses to be done depends on the number of arteries blocked on the heart. Blockages in the arteries are visualized during an examination that aims to "color" the arteries of the heart; coronary angiography.
From 1 to 3 bypasses are commonly done, but it may rise to 6 or more.
The risks of surgery
The most serious risks associated with coronary artery bypass surgery occur on average from 1 to 2% of the cases.
A commonly performed surgery
It is one of the most practiced surgeries in the world. It is very safe and the operating techniques are constantly evolving.
The lowest, most serious risks
Among the most serious risks are death, strokes (heart attack or paralysis), or coma. Fortunately, they are rare, but can occur during, immediately after surgery or even a few days later.
And the other risks
Other less serious risks include cardiac arrhythmias (heart beating too fast or too slow) that occur in one-third of these patients, the need for blood transfusions, infections and kidney problems to name the most important ones.
Depending on your age or the presence of other important diseases, the risks may be greater. There are never two identical patients, each having a different medical history: ask your doctor to explain as needed.
Once the presentation of these risks and benefits of bypass surgery is completed, a consent sheet must be signed by the patient.
Bypass surgery is performed under general anesthesia. The surgeon accesses your heart through an opening in the chest.
To reach the heart, an opening of the rib cage is made. This opening must allow the surgeon to do the necessary work.
We see the heart beat
Once this opening is done, we see the heart moving between the two lungs. We see it slip into its pocket, the pericardium.
The pericardium is open and the arteries of the heart are accessible.
The arteries to be repaired are identified
The surgeon can then identify the bypasses to be performed and proceed to the sampling of the vascular conducts (vein and artery) for the bypasses.
We prepare the conducts for the bridges
In the vast majority of cases, a vein in one leg and the left internal mammary artery are used to make the bridge over narrowed arteries in the heart.
It is possible, in some cases, to use other veins from the thigh or back of the leg, or other arteries such as the right internal mammary artery on the right edge of the right chest or a radial artery that is found in the forearm towards the wrist. It is this artery on which one feels the pulse in the wrist.
Two possible operative techniques
Currently, there are two ways to do bypass surgeries.
• A first way allows to operate the heart while the contractions are stopped.
• A second possibility is to operate the heart while it is still beating.
Technique without cardiac contraction
The first way requires the use of a pump to ensure extracorporeal circulation (artificial heart and lungs).
The heart is cooled to decrease oxygen requirements. Once cooled, it stops beating. He is like a hibernating bear.
The blood short-circuits the heart through pipes connected between it and the pump.
This device allows the blood to be oxygenated, substituting the lungs during the operation. Once the blood is oxygenated, the pump returns to the aorta. The circulation is maintained by the pump instead of the heart.
Beating heart technique
The second way allows the surgeon to perform bypass surgery while the heart continues de beat.
The circulation pump is not necessary.
However, as the heart constantly moves, the area where the bypass is done is immobilized with an instrument to stabilize the region of the heart to operate.
Small pipes sewn by a very fine thread
To stitch the bypasses, the surgeon uses an operating microscope (magnifying glasses) placed on his glasses in order to clearly see the bypasses to be made as they are small and the thread used is as thin as human hair.
Verification of the blood passage in the bypasses
When the bypass is completed, the surgeon uses a special device to check if the bypass fonctions and concludes if the operation was successful.
If it has cooled, warm the heart
In the event that the surgery is done with the heart-lung pump, it is time to put the heart back to work. The pre-cooled heart is "warmed up" to about 22 degrees, and it gradually resumes its work under the meticulous eye of the surgeon and the assistance of the health professional controlling the pump.
Temporary heart stimulator
Before closing the chest, temporary pacemaker wires will be placed on the heart to speed up the rhythm as needed. Chest drains (pipes) will be installed around the heart and lungs to drain air and blood.
And we close it all
The wounds will then be closed with steel pins to solidify the sternum (thorax) and resorbable sutures (melting stitches) or metal staples will be placed on the skin.
Intensive care surveillance
The patient is then transferred to a bed in the intensive care unit and wakes up a few hours later.
A certain euphoria accompanies the first hours after the surgery. Human nature being what it is, the patient is happy to be alive and the surgery is behind him ...
The next day is often very different. The energy level is low. A certain depression can settle for one or two days ... then, the energy returns and the postoperative progress follows.