Research On Correlation Between Carotid Elasticity Measured By Echo Tracking Technique And Coronary Artery Diseases

Objective1.To evaluate the stability and the reproducibility of echo tracking technique which used to measure carotid elasticity.2.To investigate the correlation between carotid elasticity measured by echo tracking technique and coronary artery diseases(CAD).Materials and Methods1.Alokaα10 color doppler ultrasonograph with softwares of echo tracking technique and e-DMS(Digital Manage System),linear array probe,frequency from 7.5MHz to 13.0MHz,linked with electrocardiolead.2.Totally,40 patients in hospital were examined on both carotid arteries by echo tracking technique.30 patients were examined to evaluate the reproducibility of this technique.Every common carotid artery(CCA) was checked 3 times.The examinations were completed by one doctor.5 patients were examined to evaluate the stability of this technique between different examiners.They were examined by two doctors.Every CCA was checked 3 times by each doctor.Another 5 patients were examined to evaluate the stability of this technique between different times.Every CCA was checked 3 times every time.The doctors skillfully master this technique.3.Totally,103 cases suspected with CAD were examined by cardioangiography (CAG) and echo tracking technique on carotid arteries.All the cases were divided into non-CAD group(group A:control group) and CAD group according to the results of CAG.Then,CAD group were divided into four groups(group B,C,D and E) according to the degree of stenosis of coronary arteries.Compare carotid elasticity parameters in the five groups measured by echo tracking technique included pressure-strain elastic modulus(Ep),stiffness parameter(β),arterial compliance (AC),and pulse wave conducting velocity(PWVβ).Analyze the relationship of these parameters and the degree of stenosis of coronary arteries. Results1.Reproducibility test:To statistically analyze the parameters of echo tracking technique measured three times on both left and right CCA.ICCs of parameterβ,Ep, AC and PWVβon both left and right CCA are all larger than 0.90.So it should be considered that the reproducibility of these four parameters is very good.ICCs of parameter AI on both right and left CCA are both less than 0.75.So the reproducibility of AI is poor.2.Stability test:ICCs of parameterβ,Ep,AC and PWVβon both left and right CCA are all larger than 0.90,both between different times and between different examiners. It is proved that the stability of these four parameters is very good both between different examiners and between different times.ICCs of parameter AI between different examiners and between different times are less than 0.90 but larger than 0.75. So the stability of AI is comparatively good.3.Ep,βand PWVβin the CAD group are significantly higher than those in the control group(P＜0.05).Ep,βand PWVβincreased with the degree of stenosis of coronary arteries.The correlation showes statistical differences in different groups (P＜0.05).There is no significant difference among the five groups about AC(P＞0.05).Conclusions1.As a technique to measure carotid elasticity,echo tracking technique has high stability and reproducibility.2.Ep,βand PWVβexamined by echo tracking technique and the degree of stenosis of coronary arteries examined by CAG correlate.Ep,βand PWVβas carotid elasticity parameters measured by echo tracking technique could be considered as one of the independent risk factors.Its value on precaution and treatment of CAD deserves further research.