In view of this, it is impossible to say that the doctor did not take into account the patient's own physical needs before surgery.

The doctor used a mechanical valve on this patient during the first surgery for one reason only: there was no other choice.

Bioprosthetic valves are expensive. Patients may be able to afford them, but their bodies may not be able to tolerate them. It is like buying an expensive piece of clothing that does not fit you, no matter how expensive it is. This once again shows that the disease does not discriminate between rich and poor patients.

The compatibility of biological valves is much better than that of mechanical valves. Anticoagulants only need to be taken for half a year after surgery, which is an advantage over mechanical valves. It is more friendly to women who want to get pregnant. The problem is that the manufacturing process of biological valves is subject to physical limitations such as materials science, and the finished products are often not as good as mechanical valves, resulting in limited use conditions.

The simplest example is that when the aortic root of the patient in front of you is too thin to be less than 19 mm in diameter, only mechanical valves can achieve such a small-caliber valve. If biological valves can be made with the same diameter of less than 19 mm, there are relatively few manufacturers with such manufacturing processes, and the range of products that patients and doctors want to carefully select is narrowed. Not only that, even if the size of less than 19 mm can be placed in the original caliber of the mitral valve, the effective valve area of ​​the biological valve is much smaller than that of the mechanical valve.

The key function of a valve in the human heart is the effective area of ​​the valve, not other things. To be more specific, it refers to the leaflet area of ​​the valve except for the opening and closing joints.

What are the benefits of a large effective valve area? The daily job of the valve leaflets is to constantly withstand the impact of blood flow from the heart and large blood vessels.

When the valve leaflets are closed, facing the huge waves of blood flow, the large valve leaflets close tightly and can withstand the huge impact of the blood flow like a solid large dam.

The hemodynamics when the valve leaflets are open is more important. This is when the blood rushes out from the heart to nourish other organs throughout the body. The best effect is to open the gates of the dam to release the flood. The effective area of ​​the valve leaflets is large, and the gates are opened wide enough, so that the blood in the heart, like stored in a reservoir, can be released, avoiding the residual blood in the heart that increases the burden on the heart, and at the same time will not cause insufficient blood flow and nutrition to other organs in the body.

...

...

What if the effective area of ​​the valve is not large enough? From the above principle, we can infer the causes of various symptoms caused by common valvular insufficiency and valvular stenosis in clinical practice.

The human heart has a total of four valves.

Among them, the mitral valve and aortic valve are located in the left atrium and left ventricle, and bear the hemodynamic pressure of the systemic circulation, which is a huge pressure. Compared with the pulmonary valve and tricuspid valve of the pulmonary circulation, their tasks are heavier and their status is more important.

The mitral valve is more important and more prone to problems than the aortic valve because it is located between the left atrium and the left ventricle, at the root of the aorta. Its location is rather tricky, and for many patients the mitral valve has a smaller diameter than the aortic valve, resulting in limited choice of valve models.

The surgeon in charge is not saying that the situation is not good. Combined with what Zhang said, it should be that after the doctor opened the patient's heart during the operation, he saw: Oh, the patient's body physiological structure is not good, and it is estimated that the only way to replace the valve is to replace it with a mechanical valve.