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CORONARY SURGERY: THE BYPASS SURGERY

- Principle and indications of the bypass surgery
- The vessels used to make the bypass surgeries
- Description of the surgical intervention

Description of the surgical intervention

Since some years, the progresses of the medical imagery and in particular the videoscopy techniques, have been permitting to achieve aorto-coronary bypass surgeries without having to open the thorax.

Nevertheless, these techniques are now reserved to very particular cases, and the surgeon still must achieve an opening of the thorax to be on direct contact with the heart and its arteries.

a - The classic coronary bypass surgery, by opening of the rib cage

This intervention requires an important precision from the surgeon; it lasts around 1 to 2 hours, but very much depends on the surgical team and the number of bypass surgeries to achieve.

In a first stage, the physician takes the vein at the level of the leg, the internal saphena vein. This vein is taken from the ankle to underneath the knee, on the internal face.

If he wants to achieve a bypass surgery with an internal mammary artery, he dissects this artery situated in the thorax (very close to the sternum) and sections it in its terminal portion (the one that normally brings blood to the muscle). All small collateral arteries are blocked with threads, so as blood only heads toward the heart artery.

Then, he stops the heart and thus achieves an extra corporeal circulation: the aorta is disconnected from the heart and connected onto a machine assuring the heart function. This machine also recovers blood coming from the veins, and then oxygenates it before re-injecting it into the aorta.

This technique permits to stop the heart so as the surgeon can achieve the bypass surgeries under good conditions. The surgeon also protects the cardiac muscle by injecting the cooled blood or the warmed blood (according to the teams, this procedure is called cardioplegia), in the vein of the heart or in the aorta.

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Once the vein has been taken, and/or the internal mammary artery has been opened (to put it back on another artery), the extra corporeal circulation set up and the heart stopped, the surgeon can start the bypass surgeries.

Thus, he delicately perforates the sick coronary artery, so as to achieve a hole, downstream the obstacle, in which the “bridged” vessel will come to stand. This stage is very delicate because it is the guarantee of a quality bypass surgery.

Then, the venous and/or arterial bridges are plugged in the holes thus achieved, and fixed with the help of very thin threads.

The termination stage of intervention consists in warming or cooling the heart so that it starts again, and then to disconnect the extra corporeal circulation.

Monitoring is necessary thereafter in a surgical cardiological intensive care unit, for some hours.

b - Operation by videoscopy (a mini-invasive surgery)

This type of an operation is rather reserved to a bypass surgery on only one heart artery, with the internal mammary artery. Some teams attempted the venous bypass surgeries that proved to be bad quality.

Its enormous advantages are to avoid the opening of the thorax (thoracotomy), the extra corporeal circulation, and the stoppage of the heart. However, its main disadvantage is not to have a very large sight of the operative field and not to be able to see a bleeding that could take place outside of the field of vision.

Thus, the surgeon achieves an incision on the left side of the thorax, introduces his camera and achieves the dissection of the internal mammary artery. He regularly sutures this artery so as bleedings are as weak as possible. Then, he cuts the artery in its extremity and sutures it temporarily.

The other stage consists in achieving a hole in the sick coronary artery so as the bypass surgery of the mammary artery can be achieved. Finally, the mammary artery is fixed on to the sick coronary artery (downstream the coronary lesion) with the help of suture threads and with the heart beating, which requires a considerable experience.

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File last reviewed on dec 18, 2011