Chapter 2545: Surgical Technique

Holding the note with the precautions written on it, Xie Wanying continued communicating with the teacher on the other end: "When you trim, Teacher Ye, please leave the vena cava vessels a bit longer."

Oh, oh, oh. Ye Chuanguang picked up on something and said, "What operative technique are you planning to use? The child on your side is nine, not yet ten, right?"

Heart transplantation is divided into orthotopic heart transplantation and heterotopic heart transplantation. Orthotopic heart transplantation is easy to understand: the patient’s diseased heart is removed, and the donor heart is placed into the original cardiac position. Heterotopic heart transplantation does not remove the diseased heart; instead, the donor heart is connected to the patient’s original diseased heart, providing supportive assistance to the failing heart, essentially functioning as a purely biological cardiac assist device.

Heterotopic heart transplantation is performed very rarely, because there’s no real future for it. Generally, for end-stage cardiomyopathy like that of Zhu Xing, even implanting a cardiac assist device as a bridge cannot fundamentally eradicate the underlying disease.

Heart transplantation basically revolves around orthotopic heart transplantation. Orthotopic heart transplantation sounds simple: just remove the diseased heart and let the donor heart replace it. In actual practice, it is anything but simple.

The heart has a total of eight vessels entering and leaving that all need to be anastomosed. The most difficult among these is the pulmonary venous group of the left atrium. On both sides of the posterior wall of the left atrium there are two orifices for the superior and inferior right pulmonary veins and two orifices for the superior and inferior left pulmonary veins. You can imagine how complicated that is.

Similarly, the right atrium has two anastomotic sites for the superior and inferior venae cavae that also have to be connected, which is not easy.

If all of these numerous vessels are scrupulously anastomosed one by one, this is called the Whole Heart Method of heart transplantation. This operative approach is the most complex and the most time- and labor-consuming; the more anastomoses you sew, the higher the risk of anastomotic leakage and related complications. In surgery, the principle has always been: the simpler the steps, the better; the fewer sutures, the better.

To save operative time and protect the myocardium, and to reduce postoperative complications, surgeons initially adopted a somewhat expedient technique for heart transplantation, specifically doing the following: when removing the patient’s heart, they only cut away the ventricles and leave the recipient’s left and right atria in place. The donor atria are directly anastomosed to the recipient atria, thereby completely bypassing the multiple complex anastomoses of the left and right atria. This is abbreviated as the double atrial method, also known as the standard method of heart transplantation.

In pediatrics, if the child is very young—especially in neonates—the vessels are too thin, and even under magnification it is very difficult for surgeons to perform fine suturing at multiple anastomotic sites. In such cases, using the double atrial method is of course the best option.

For older children and adults, the double atrial method is rarely used anymore. The reason is that this operation has a major drawback.

We know that the heart has a conduction system that allows it to beat rhythmically. The highest pacemaking point of this conduction system is the sinoatrial node, which primarily controls how many beats per minute a person’s heart makes. The sinoatrial node is located precisely in the upper part of the right atrium.

The double atrial method preserves both the donor and the recipient right atria, resulting in two sinoatrial nodes. It’s equivalent to installing two engine control systems in the heart—so which one is the heart supposed to obey? Of course it will become disordered; arrhythmias are inevitable.

After recognizing this drawback, surgeons later modified the procedure, leading to the emergence of the now most commonly used bicaval method. Put simply, this bicaval refers to anastomosing the superior and inferior venae cavae of the right atrium.