In view of this, it is impossible to say that the doctor did not consider the patient's own physical needs before surgery.
The first time the doctor used a mechanical valve for this patient, there was only one reason left: there was no other choice.
Bioprosthetic valves are relatively expensive, and patients can afford them, but unfortunately, patients may not be able to physically accept them. For example, if you buy an expensive piece of clothing, if it doesn’t suit you, it doesn’t suit you, and it doesn’t matter how expensive it is. Once again, it shows that the disease does not treat people differently.
The patient is poor or rich.
The compatibility of biological valves is much better than that of mechanical valves. The post-operative anticoagulant medication only needs to be taken for half a year, which has advantages over mechanical valves. It is more friendly to women who want to become pregnant. The problem is the production of biological valves.
The process is subject to physical limitations such as materials science, and the finished product is often not as good as the mechanical valve, resulting in limited use conditions.
The simplest example is that when the patient's aortic root is too thin to be less than 19 millimeters in diameter, only a mechanical valve can achieve the best fit for a small-diameter valve. If a biological valve can achieve the same diameter of 10 millimeters,
For sizes below nine millimeters, there are fewer manufacturers with such manufacturing processes. Patients and doctors want to carefully select the best products and the range has become smaller. Not only that, even if the size is below nineteen millimeters, it can just fit
At the original diameter of the mitral valve, the effective valve area of the biological valve is much smaller than that of the mechanical valve.
What really plays a key role for a valve in the human heart is the effective area of the valve rather than anything else. To be more specific, it refers to the leaflet area of the valve except the opening and closing joints.
What are the benefits of having 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 leaves are closed, facing the huge waves of blood rushing towards them, the large valve leaves close tightly and can withstand the huge impact of the blood flow like a strong and large-volume dam.
Hemodynamics when the valve leaflets are open are more important. At this moment, the blood flow rushes out inside the heart to nourish other organs in the body. The best effect required is to open the dam to release floods. The effective area of the valve leaflets is large, and the gate is opened.
It must be large enough so that the blood flow stored in the heart can flow rapidly to avoid remaining in the heart and increasing the burden on the heart. At the same time, it will not lead to insufficient blood flow and nutrients in other organs of the body.
What will happen if the effective use area of the valve is not enough? It can be deduced from the above principle that valve insufficiency and valve stenosis are common clinical causes of various physical symptoms.
The human heart has a total of four valves.
Among them, the mitral valve and aortic valve are on the left atrium and left ventricle, and bear the hemodynamic pressure of the systemic circulation. They are under great pressure. Compared with the pulmonary circulation and the tricuspid valve of the pulmonary circulation, their tasks are heavier, and their status is more important.
A little more.
The mitral valve is more important than the aortic valve and is prone to problems because it is located between the left atrium and the left ventricle, at the root of the aorta, and its location is tricky. In many patients, the caliber here is smaller than the aortic valve.
The large diameter of the position results in less room for valve models to choose from.
What the surgeon said is not very good at the moment. Combined with Zhang's words, it should be that after the doctor opened the patient's heart during the operation, he saw: Oops, the physiological structure of this patient's body is not very good. It is estimated that the only way to replace it is with a mechanical valve.
