| The theory of systemic circulation shows, the heart is like a pump, which ejects the blood from it and flows into the organs and tissues through arteries. Blood in the arteries can provide oxygen and nutrition to the organs and tissues. The systemic circulatory is very important for people to keep heath. Now, it is popular to use the Doppler ultrasound in detecting the blood flow curve and diagnosing vascular diseases in clinical and research work.For long decades, researchers have done a lot of work in studying the elastic function of arteries, and have made some progress. Based on the existing research results, we know that the elastic function of the artery wall could maintain the blood to keep flowing forward in the certain arteries during diastole. In recent years, some scholars have put forward the theory that, during diastole, the elastic function of the artery wall does not only maintain the blood to keep flowing in certain arteries, but also push some blood into the connected arteries, which means that certain arteries of the body can provide some blood for its connected arteries during diastole. But that theory is lack of experimental proof, especially the proof in Doppler ultrasound. On the other hand, the elastic function of arteries can reflect the elasticity of the artery wall directly. Could we quantify the elastic function of arteries in order to evaluate the elasticity of the artery wall, and then diagnose the AS of arteries at an early age? Based on the questions above, we took focus on the AAO, which is connected with the heart directly, and did a lot of research work on it.1. 80 healthy volunteers(20~40 years old) were collected in this study. With the subjects in the left lateral decubitus position, two-dimensional images of the AAO were acquired at the parasternal left ventricular long axis view. The average display length of the AAO(from the aortic valves to the bifurcation of the INA from the aorta) was measured in this section. Then AAO was divided equally into 6 segments, each segment has the same length. Doppler flow velocity of the middle point of each segment was recorded by Doppler ultrasound. After that, we analyzed the Doppler flow velocity to make sure the pattern of blood flow at each checking point of the AAO.On the other hand, Doppler flow velocities of AAO and INA were recorded by dual PW, Doppler flow velocities of AAO and AOAR were also recorded by dual PW. The ECG was used as the time guide, and the Doppler flow velocities of AAO and INA, AAO and AOAR were compared and analyzed to make sure whether the AAO can provide blood during diastole, after the AV was closed, to the INA and AOAR. Then we proposed that the AAO as an elastic pump of systemic circulation during diastole.2. Compared with the EF of the heart, we proposed a new parameter, the SF, to evaluate the pumping capacity of the AAO. Based on Doppler ultrasound, we used the subsection method, calculated the SF of 80 healthy volunteers(20~40 years old). And the calculated SF provided a standard in evaluating the pumping capacity of the AAO.3. 20 healthy volunteers of 20~35 years old, 20 healthy volunteers of 35~50 years old and 20 healthy volunteers of 50~65 years old were collected. Based on Doppler ultrasound, we used the subsection method, calculated the SF of volunteers of each group, and compared the difference between them. Then we analyzed the SF changes by aging.4. 20 patients(50~65 years old), with high blood pressure for more than 5 years and abnormal blood lipid, the diameter of the AAO root of those patients were significant widen(>35mm), and all the patient were diagnosed as early AS in AAO. The SF of those patients were calculated and compared with that of healthy volunteers with the same age group. Then we estimated the effect of SF in diagnosing the AS at an early age.The results show that:1. The elastic function of the AAO wall does not only maintain the blood to keep flowing in it, but also push some blood into the connected arteries, which mean that AAO can provide some blood for its connected arteries during diastole, to keep the normal physiological function of certain organs. AAO is an elastic artery, it can store some blood in it during systole, and push the blood in it to flow forward during diastole after the AV is closed, some of the blood will flow into the INA or AOAR eventually. So the AAO can provide blood to the INA or AOAR during diastole, and during this time, the AAO does not accept any blood from the heart. This function of AAO in diastole is very similar with the function of heart in systole. So we innovatively proposed that the AAO as an elastic pump of systemic circulation during diastole.2. Compared with the principle of mechanical contraction of the heart, the SF can be a new parameter in evaluating the pumping capacity of the AAO. And we finally calculated the SF of healthy adults(20~40 years old), which was 21.04%±0.14%.3. Based on the statistical analysis of SF values of three different age groups, we found that the SF value of healthy adults is reduced with age growing. The result shows that pumping capacity of the AAO is decreasing with age growing. On the other hand, the SF values of 50~65 group were significant lower than the other groups, which indicated that the decreasing of pumping capacity of AAO was significant among those people who are more than 50 years old.4. Based on the statistical analysis of SF values of healthy volunteers and patients with early AS in AAO in the same age group, we found that the SF values of healthy volunteers were significant higher than the patients with early AS in AAO. Which indicated that the SF value is a reliable parameter in evaluating the changes of elasticity of AAO wall and diagnosing early AS in AAO.The results of the study above show that AAO can provide blood to other arteries during diastole, it is an elastic pump of systemic circulation. The parameter of SF, can evaluate the pumping capacity of AAO and helping in diagnosing the early AS in AAO. |
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