In view of this, it is impossible to say that the doctor did not consider the preoperative factors of the patient's own physical needs.
The first time the surgeon used a mechanical valve on this patient, there was only one reason: there was no other choice.
?Biological valves are relatively expensive, and patients can afford them, but unfortunately, patients may not be able to bear them. It's like buying an expensive piece of clothing. If it doesn't suit you, it doesn't suit you. It doesn't matter how expensive it is. It once again shows that the disease treats people regardless of whether the patient is poor or rich.
The compatibility of biological valves is much better than that of mechanical valves. Postoperative anticoagulant medication only needs to be taken for half a year, which has advantages over mechanical valves in this regard. 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 patient's aortic root is too thin to be less than 19 millimeters in diameter, only a mechanical valve can achieve such a perfect fit for a small-diameter valve. If bioprosthetic valves can be produced in the same size of less than 19 millimeters in diameter, there will be fewer manufacturers with such manufacturing processes, and the range of products that patients and doctors want to carefully select will be narrowed. Not only that, even if the size is less than 19 mm, which can just fit into 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 in a valve inside the human heart is the effective use area of ??the valve and not 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 over, the large valve leaves close tightly and can withstand the huge impact of the blood flow like a strong 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 is to open the dam to release floods. The effective area of ??the valve leaflets is large, and the gate is opened wide enough, so that the blood flow stored in the heart can be discharged thousands of miles away, avoiding remaining in the heart and increasing the burden on the heart, and at the same time, it will not lead to insufficient blood flow and nutrition in other organs of the body.
What will happen if the effective use area of ??the valve is not enough? From the above principle, it can be deduced that clinically common causes of valve insufficiency and valve stenosis lead to 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 they bear the hemodynamic pressure of the systemic circulation. They are under a lot of pressure. Compared with the pulmonary circulation and the tricuspid valve of the pulmonary circulation, their tasks are heavier, and their status is less important. Somewhat.
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 location results in less room for valve models to choose from.
"The surgeon's words are not very good at the moment. Based on Zhang's words, it should be that after the doctor opened the patient's heart during the operation, he took a look: Oops, this patient's body's physiological structure is not very good. It is estimated that the only way to replace it is with a mechanical valve. (Remember the website address: www.hlnovel.com