Conventional Bypass Surgery Summary
Although this is the traditional method of CABG that has evolved to its near perfect state over the past four decades, there is nothing standard or uniform about its implementation. Different surgeons and different centers have their own unique modifications and improvements. I will attempt to explain some common protocols that are used in most institutions.
Conventional CABG is performed through a vertical incision down the front of the chest that splits the breast bone. It is an open heart operation. This means that the heart-beat is stopped temporarily while the circulation of blood is maintained artificially (by the “heart-lung machine”). With the patient hooked up to the heart-lung machine, the surgeon places a clamp on the aorta, which is the large artery arising from the left ventricle. The heart beat is then stopped, so that surgical connection between the graft and coronary artery can be achieved with greater ease and precision than if the heart were to continue moving. The heart can be stopped by different methods.
Cardioplegic Arrest with CABG
In this method, the heart is stopped, and even “protected” from damage during the period of surgery, by injecting a solution called CARDIOPLEGIA (cardio: “heart”, plegia: “paralysis”). This cardioplegia solution is injected through the aorta into the coronary arteries, when it is called “antegrade cardioplegia”, or in the reverse direction from the coronary sinus into the coronary arteries, when it is called “retrograde cardioplegia”.
Fibrillatory Arrest with CABG
Surgeons who use this technique do not use cardioplegia to stop the heart beat. Instead, they apply a weak electric current to the heart that stops its contraction, and induces a condition called Ventricular Fibrillation.
With the heart thus arrested, the CABG operation is carried out by connecting the graft to the diseased coronary artery using thin sutures. The graft may be an artery like the Internal Thoracic Artery (ITA) that I have discussed in an earlier article on CABG, or a vein like the Saphenous Vein (SV).
