Quantitative Evaluation Of Carotid Elasticity In Patients By Newly E-Tracking Technique

Atherosclerosis (AS) is the most common and important one in the group of vascular diseases named as arteriosclerosis. The common feature for arteriosclerosis is that noninflammatory, retrogressive and hyperplasic changes happen to artery, which results in the affected vessel walls incrassated, hardened, lost elasticity and shrunk in lumen size. For AS, besides the above lesions, the affected artery also suffers from accumulation of lipidic and compound carbohydrate, bleeding, thrombosis, proliferation of fibrous tissue and calcareous deposition that starts with the intimae successively along with gradual deterioration and calcification of arterial media. The pathologic changes caused by AS involve mainly in the large elastic arteries such as the aortas and the middle muscular elastic arteries (mostly the coronary arteries and cerebral arteries, then the arteries of limbs and trunk, renal artery and mesenteric artery next). The affected arteries become less elastic, more brittle and easy to break; meanwhile, the arterial lumen turns narrow or even entirely off or develops into aneurysm, which may cause the entire circulatory system or individual organs dysfunctional. As per the statistic data released by American College of Cardiology (ACC) in 2004, AS is still the number one killer disease in America. Along with the development of economy and society, the blood vessel diseases have already ranked the top of all by incidence rate, and become a global heavy burden and a challenge to face in the new century. Long-term research has found out that carotid artery atherosclerosis (CAS) is approximately going on simultaneously along with atherosclerosis of aorta, but earlier than the occurrence of coronary atherosclerosis. CAS is significantly related to coronary artery disease (CAD) and ischemic cerebrovascular disease; meanwhile, the severity of CAS increases markedly along with the progress of coronary atherosclerosis. The functional lesion of endothelial cells is often the initiating step of AS occurrence, which is frequently accompanied with changes of arterial elastic function simultaneously. Therefore, it is of remarkable significance to research the early functional change of arterial elasticity for understanding the occurrence and progress of AS as well as the prevention and treatment of its complications.The reduction in arterial elasticity is the comprehensive manifestations of early lesions to vessel walls resulted from various cardiovascular and cerebrovascular risk factors, and it is also the specificity and sensitivity indicator of early vascular disease. Since it is hard to carry out directly morphological observation and quantitative estimation of arterial construction, a practical way is to measure the arterial expansibility or elasticity for the pathological changes of artery. Considering the fact that arterial elasticity is hard to measure directly, noninvasive methods are often used to quantify the arterial elasticity, of which the measured parameters include mainly internal diameter difference, pulse pressure, pulse wave velocity (PWV), reflected pressure wave's argumentation index (AI) in the systolic phase, elasticity index of large arteries, elasticity index of small arteries, pulse wave's attenuation parameter in the diastolic phase, concussion wave analysis of cuff internal pressure on measuring blood pressure, measurement of pulse pressure wave and ultrasonic Doppler measurement of arterial diameter's variation in response to pressure. Clinically, arterial PWV is always used as a noninvasive method for evaluation of arterial elasticity. However, along with the rapid development of science and technologies, it is reported that ultrasonic examination is used increasingly to evaluate the arterial elasticity. Peterson put forward the physical variables of elastic coefficient (Ep) and rigidity (6) in 1960. In recent years, ultrasonic technique has advanced to the level high enough to measure invasively the microvariation of arterial expansibility, peripheral stress and intima-media thickness (IMT), which are very helpful in acquiring important data of blood vessel like expansibility and compliance, and has become an important invasive measuring method for arterial functions. Along with the continual improvement of ultrasonic technique, such approaches as Tissue Doppler Imaging (TDI), Tissue Velocity Imaging (TVI) and Integrated Backscatter (IBS) have been used to evaluate arterial elasticity clinically. As proven by a great deal of research, carotid IMT measured with high resolution B-type ultrasonic imaging method has been widely recognized as a reliable indicator in diagnosis of CAS. And it is believed that IMT has a fairly good linear relationship with arterial elasticity. As mentioned above, arterial elasticity is a reliable indicator reflecting the early functional change of arterial buffer system. Echo -tracking (ET) technique is a brand new technique available in a-10 Color Doppler Ultrasound Diagnostic Apparatus that is developed by Aloka Corporation. It is able to conduct real-time tracking and record of blood vessel frontal and rear walls' kinematic trace, compute automatically the variance of blood vessel's internal diameter in response to cardiac cycle, and display the result in form of curve. Its built-in digital image management system (e-DMS) is able to compute automatically such elastic indexes as Ep,β, AC, AI ,PWV, Dd,Ds.Making itpossible to evaluate artery vessels' elastic functions quickly and accurately.Objective Quantitative evaluation of carotid elasticity in patients by newly E-Trackingtechnique.Methods Accroding to clinical information and 2-dimensional ultrasound data that atotal of 109 cases were divided into four groups: carotid artery atherosclerosis withsymptoms group (32 cases),carotid artery atherosclerosis without symptoms group(26cases),high risk human group (26 cases)and normal group (25 cases). The change ofartery function were evaluated by newly E- Tracking technique.Results 1. Among the three groups of age, weight, gender showed no significant difference. 2. There were no significant difference in carotid elasticity parameters between two sides in those patients with unilateral plaque. 3. Compared with the high risk human group and normal group, data of Ep,β,PWVβ,AI and IMT were significantly higher in atherosclerosis (P<0.01). 4. In atherosclerosis group, PWVβwas positively correlated withβ, Eρ, IMT and negatively correlated with AC, while there was no correlation among Ep,β, AC, IMT and AI.Conclusions 1. Artery atherosclerosis is a kind of morphological changes and functional damage of the disease co-exist. Atherosclerosis and arterial elasticity is reduced at the same time, artery atherosclerosis is a factor in arterial elasticity reduced. 2. Artery atherosclerosis in patients with decreased degree of flexibility in the appearance of clinical manifestations related. Atherosclerosis in patients with clinical performance. 3. The extent of atherosclerosis and reduce the degree of arterial elasticity is the same. The degree of atherosclerosis are more serious, the arterial elasticity are more obvious decline. Changes in arterial elasticity can be used as to determine the extent of atherosclerosis. 4. Echo tracking technique for the detecte patients with arterial elasticity, with non-invasive, high accuracy, good repeatability, the advantages of simple operation, was to evaluate the artery atherosclerosis in patients with a flexible approach has important significance. Atherosclerosis at the diagnosis, treatment and research has important application value. Vascular echo tracking techniques and morphology can be detected to evaluate the application atherosclerosis and its risk and provide more comprehensive and valuable information. 5. Vascular echo tracking technology to capture at the time of early atherosclerotic vascular changes in flexibility, from the implementation on the real meaning of the ultrasound diagnosis of vascular function, happened in the artery IMT thickening, plaque morphology, such as a change made before the judge, thereby to achieve early diagnosis of atherosclerosis, earlytreatment and prevent or delay the occurrence of the purpose of arteriosclerosis.