The patient is made unconscious by giving general anesthesia in this surgery which is performed by the teamwork of expert doctors and other paramedics. A longitudinal central incision is put in the middle bone of the chest, so as to reach up to the heart. At the same time, another surgeon starts the process of harvesting the veins and arteries for grafting from his limbs.
There arteries or veins preferred as graft for bypass surgery are :
- LIMA : Artery supplying blood to the muscles and skin of the left side of the chest
- LRA : Artery supplying blood to the outer part of left hand
- RIMA : Artery supplying blood to the muscles and skin of the right side of the chest
- SVG : Veins of the legs
According to the conclusions drawn from different research, generally, LIMA graft remains active and patent for more than 15 years and other grafts for 7-12 years. Many factors influence this.
The most important job of a surgeon is to join this graft conduit proximally with aorta and distally with the coronary artery having blockage. The cardiac surgeon has to take stitches in the walls of arteries / veins having thickness up to 0.5 mm and hence, he has to perform this surgery wearing microscopic lens.
This surgery can be done by two methods :
- With Heart and Lungs Stand Still (On Pump Surgery) : Blood from entire body is taken out through the vein and is passed through the heart lung machine. This machine serves the functions of the heart and lungs – eliminates carbon dioxide and other harmful waste products, adds oxygen to the blood and keeps the blood circulating. At the beginning of the surgery, the heart is cooled with cardioplegia solution so that it stops functioning, and after the surgery is over it is restarted by giving electric shock.
- With Beating Heart (Off Pump Surgery ) : Only a part of the heart surrounding the coronary artery where the surgery is to be performed is made stable with the help of an instrument called Octopus. The remaining part of the heart keeps on beating and pumping blood in the normal manner.
More and more surgeries are performed by this beating heart method in last 10 – 20 years. Conclusions of studies consider this method safer and less complicated for patients. Yet the final decision is taken on the basis of experience of the team of surgeons and condition of the patient.