The average thickness of the aortic valve is only 0.3 mm. Yet the aortic valve will be opened and closed nearly 2 billion times in a person's lifetime, consequently aortic valve is likely to deteriorate. Additionally, bacterial infection, aging and various other factors could also threaten the health of aortic valve, resulting in valve stenosis.
When aortic valve stenosis occurs, the valve becomes hard, inflexible, and cannot be fully opened and closed, the natural pumping mechanism of blood is affected, resulting in insufficient blood output. The heart also has to increase its power just to pump out the same amount of blood. Over time, this long-term "overworked" state will permanently damage the heart muscle, causing heart failure. Heart failure could seriously affect patient’s daily activities, even lead to death.
Currently, there are only two treatment options for aortic stenosis, first is through surgical means, the second is through taking medicine. However, taking medicine is not a "root cause" solution for severe aortic stenosis, and only relieves the symptoms, in some cases, taking medicine could even be harmful. Therefore, surgical treatment has become the main treatment for more patients with aortic stenosis. There are two main surgical treatments for aortic stenosis, namely traditional open heart surgical treatment, and the latest minimally invasive interventional treatment.
In the surgical treatment, anesthesia should be carried out first, cardiopulmonary bypass should be established in the state of cardiac arrest. A 20cm incision in the chest was made and the heart was cut. The diseased valve was removed and replaced with artificial valve.
The whole operation time and postoperative recovery time are relatively long, some elderly patients with weak body conditions, or poor cardiac function may not be able to withstand surgical operation; after surgery, patients may also suffer the risk of stroke, myocardial infarction, and even death.
Minimally invasive interventional surgery, is when only a small incision, commonly in the femoral artery of the thigh, a folded artificial valve is transported through the catheter and released at the site of aortic valve, replacing the diseased valve, the normal opening and closing of the heart "valve" is restored, and blood circulation can now flow unobstructed.
During TAVR, the biological valve is completely folded into the catheter, and the catheter enters the heart, through an artery.
The common approaches of TAVR includes：
Through the imaging and delivery system, doctors delivers the catheter to the diseased valve. After positioning, the doctor can gradually release the valve through the automatic handle; Figure 2 shows the valve in release. When the valve is completely released, the biological valve fully unfolds in the diseased valve, and replaces the function of the original valve in the patient's body.
The valve is folded and placed in the catheter. The catheter and the folded valve passes through the artery to the diseased aortic valve.
Doctors release the valve from the catheter and push the diseased area of the aortic valve aside. To ensure accurate positioning and placement of the new valve, doctors will use special X-ray equipment.
Once installed in place, the new valve will immediately start to work and restore healthy blood flow. After the test confirms that the new valve is functioning properly, the doctor will remove the catheter, close the incision, and transfer the patient to the rehabilitation area.