| Objectives:Coronary artery disease (CAD) is a kind of common syndrome, it usually shows the myocardial ischemia and hypoxia because of coronary atherosclerosis which can lead to vascular stenosis or (and) the changes of the function in coronary arteries, so some scholars call it ischemic heart disease. Epidemiological survey data to the heart disease show that the CAD is commonly occurred in the people whose age are more than 40 years,and developed rapidly in the period of 35 ~ 55 years. The average increase rate of the CAD is 8.6% every year. In To 2020, our country will reach the peak in the morbidity of cardiovascular diseases (mainly coronary heart disease).The pathological changes in coronary artery disease include three stages: lipid spots and stripes in the wall, fibrous and atherosclerotic plaques, complex lesions. In recent years, people find that the atherosclerosis may be a chronic inflammatory and autoimmune disease. And with the development of the people's living standards, the morbidity of the CAD is increasing year by year. Once the CAD patients are paroxysm, the symptom will develop rapidly, the situation will be critical, and the prognosis will be poor. Therefore, early treatment and intervention to the CAD patients may suspend or delay the pathological process and prevent the development of the coronary heart disease and myocardial infarction. Recently, the research methods in the clinical diagnosis of coronary artery disease are various, such as Electrocardiogram, Holter, Coronary Angiography, Echocardiography and so on. However, every method has its own advantages and disadvantages, and the accuracy and sensitivity is also different.At present there is still general agreement that Coronary angiography (CAG) is the gold standard for diagnosis of coronary heart disease. Doctor can understand the patient's coronary artery anatomy by static or dynamic observing the filling and disappearance situation of contrast agent and do the real-time observation to know that whether the coronary artery has stenosis,thrombosis,plaque or wall calcifications. The intuitiveness aspect and accuracy of the CAG are unmatched than the other inspection methods. However, CAG is a kind of invasive diagnostic method which demands high operating condition. Once the operator is inadvertently, the patient will appear serious complications even death. The CAG also need to use contrast agent which is very expensive. Therefore the CAG is limited extensively in a large extent.Quantitative tissue velocity imaging (QTVI) is a new technique based on the Doppler tissue imaging (DTI). The technique is greatly improved its time resolution, and it can determine and analyse the movement of different segments of ventricular myocardium simultaneously and quantitatively (up to analyse eight segments simultaneously) in the long axis and show the speed, direction and exercise time of contraction and relaxation of the ventricular myocardium, and thus QTVI can achieve the quantitative assessment of myocardial wall motion.In this study, the CAG results of the CAD group were collected as the gold standard, and the speed and time of the myocardial wall motion were measured quantitatively by QTVI technique in the CAD group and normal group. Then the results between the CAD group and normal group were comparative research to know that whether the corresponding data was different, and whether the correlation between the data of CAG results and the speed and time of myocardial wall was existed. The purpose of the research was to study the clinical significance of Q-TVI technique in the diagnosis of coronary artery disease and applied the technology to a clinical screening examination in the patients with coronary artery disease and then the results of the QTVI could provide the basis for the further examination or treatment.Methods:1 Thirty-eight CAD patients (CAD group) and thirty normal subjects (normal group) were studied by QTVI. The patients in CAD group were all confirmed by coronary angiography with a single branch or multiple branches of coronary stenosis; and the patients in normal group were excluded people with other significant cardiac disease.2 The research was operated by GE Vivid 7 color Doppler ultrasound instrument. Using QTVI, 12 points at basal and middle segments were investigated by apical 2- and 4-chamber and long axis views.3 In accordance with 16-segment division method formulated by the U.S. Society of Echocardiography in 1989, the interval, inferior, anterior, the former interval, lateral, and posterior wall were divided into 16 segments. And the revised method according to the standard of American Society of Echocardiography (ASE) was adopted to analyse the relationship between Wall segments and coronary blood supply.4 According to the levels of coronary artery stenosis,the artery would be classified into four degrees: degree I <25%;degree II 26%-50%;degree III 51%- 75%;degree IV >76%.5 Using QTVI, 12 points at basal and middle segments of posterior septum, lateral wall, inferior wall, anterior wall, posterior wall, anterior septum were sampled by apical 2- and 4-chamber and long axis views. Sampling area size was set to 4mm×4mm. The velocity and interval was drew into a Q-TVI curve. And the basal and middle segments of each wall were measured to achieve the results of Vs, Ve, Va, ICT, IRT, Ts, Te.Results:1 38 patients were measured in CAD group, 11 of them were cramped in one coronary artery, 18of them were cramped in two coronary artery, and 9 of them were cramped in three coronary artery.2 Information compared between normal group and CAD group: Age, sex and heart rate were not significant different between the two groups (P>0.05), but patients with high cholesterol in CAD group were significantly more than patients in normal group. The average blood pressure of CAD group was significantly higher than normal group (P<0.05). 3 Speed compared between normal group and CAD group: The peaks of Vs and Ve in middle segments of ischemic wall were significantly lower than the normal group (P<0.05); but the peaks of VA were different only in middle segments of posterior septum wall and inferior walls than the normal group (P<0.05).4 Time compared between normal group and CAD group: The time of IRT, ICT and Ts were significantly longer than the normal group (P<0.05); but the time of Te was not different in middle segments of inferior wall, anterior wall.5 Overall function between normal group and CAD group: The average of Vs and Ve/Va in the basal segment of six walls was significantly lower than the normal group (P<0.001).6 Compared between the degree of Coronary angiography stenosis and speed of left ventricular walls motion in the CAD group: The Vs and Ve of the walls and the degree of coronary artery stenosis were negatively correlated (P<0.05).7 Compared between the degree of Coronary angiography stenosis and time of left ventricular walls motion in the CAD group: Only ICT and IRT of the walls and the degree of coronary artery stenosis were positively correlated (P<0.05). The Ts of the anterior wall and anterior septum motion was significantly longer when the degree of coronary stenosis was increased (P <0.05), and the Te of the middle of the anterior septum motion and the degree of coronary stenosis were correlated.Conclusions:1 Using non-invasive and real-time QTVI, when the coronary artery is narrow can be estimated by measuring the motion speed and time of the corresponding wall the artery supply to. The results of the QTVI can provide the basis for the further examination or treatment. And the patients can reduce unnecessary suffering and the positive rate of CAG will improve greatly.2 People who own hypertension and hyperlipidemia are more susceptible to suffering from the CAD than normal ones. And hypertension and high cholesterol are risk factors to promote coronary atherosclerosis.3 The middle segments of corresponding walls which the coronary artery supply to exist the abnormal motion speed and time. The changes of Vs, Ve, ICT, IRT and Ts are most obviously, Vs and Ve are significantly reduced, ICT, IRT and Ts was significantly extended. Therefore, the changes of Vs , Ve, ICT, IRT and Ts can be used as the bases on initial diagnosis of coronary heart disease.4 The degree of Coronary artery stenosis and the data changes of Vs, Ve, ICT and IRT are relevant. The relevance is that the higher degree of coronary artery stenosis, the lower Vs and Ve of corresponding walls which the coronary artery supply to, and the longer ICT and IRT of corresponding walls.5 The function of basal segment can be representative of overall ventricular function. When coronary artery stenosis occurs, the diastolic and systolic functions of the basal segment of left ventricular were significantly reduced.
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