Evaluation Of Carotid Artery Elasticity In Patients With Coronary Artery Disease By Ultrasound Radio-frequency Data Technique

ObjectiveWith the improvement of living standards and the increase of life pressure,the incidence of coronary arterial disease (CAD) showed a yearly increasingtrend both in China and world-wide. The rapidly increased morbidity andincreased proportion of younger patients of myocardial infarction warn us theimportance of CAD prevention.CAD is triggered by lumen of blood vessel blockage which caused bycoronary atherosclerosis or functional spasm under a variety influence ofexternal and internal factors, and leading to myocardial ischemia and anoxiaeventually. In the two causes of lumen of blood vessel blockage, coronaryatherosclerosis is the major one.It has been shown that the risk factors and pathological basis of coronaryatherosclerosis is similar with carotid atherosclerosis. Additionally, the twodiseases are closely related in terms of occurrence and disease development. Currently, high-frequency ultrasound is the major approach for assessingcarotid blood vessels structure and elasticity by acquring high quality images.Due to the inferior advantage in terms of measurement accuracy and quantitativeevaluation of vascular function changes, traditional ultrasound diagnostictechniques have been gradually replaced by gray-scale tracking (ET) and radiofrequency data technology (RF-Data) in recent years. Accordingly, RF-Data hasbecome the main research tool for the evaluation of peripheral vascular structureand stiffness,.Due to the fact that RF-Data is more accurate and repeatable thanET, and it can achieve a quantitative evaluation of vascular structure andflexibility features simultaneously.The purpose of this study was to investigate the value of ultrasoundradio-frequency data technique in assessing carotid artery elasticity and thecorrelation between the carotid artery elasticity and the coronary arterypathology in patients with coronary artery disease (CAD).Methods1、SubjectThis prospective study included127subjectssuspected with CAD fromDepartment of Cardiology of Tangdu Hospital,89male and38females. Patientswith other cardiovascular diseases such as hypertension and diabetes mellituswere excluded.The candidates were divided into four groups: Group A:Thirty-two subjects who were free from CAD confirmed by conronaryangiography (CAG); Group B: Twenty-eight subjects with coronary stenosisrate <50%confirmed by CAG, and with no significant homodynamic changes;Group C: Thirty--three subjects with either left anterior descending (LAD) leftcircumflex artery (LCX) or right coronary arterial (RCA) stenosis≥50%or more; Group D: Thirty-four subjects sufferred2or more than2coronary brancheswithstenosis≥50%. The subjects with left main coronary artery stenosis≥50%ormore were distributed to Group D.2、Apparatus and MethodEsaote Mylab70XV ultrasound instrument was employed. LA523probewith frequency of4~13MHz was adopted. Traditional carotid ultrasound wasperformed. Carotid intima-medial thickness (IMT) and arterial stiffness weredetected using Quality IMT (QIMT) and Quality Arterial Stiffness (QAS)techniques. The ultrasound physicians were double-blinded with CAGphysician.3、Statistical analysisSPSS13.0statistical software was used for data analysis. Allmeasurements were expressed as mean±standard deviation. A single factorvariance analysis was conducted for A, B, C, D four groups. Receiver OperatingCurve (ROC Curve) was used to assess the predictive value of thesemeasurements for CAD. The area under the ROC curve was consideredsignificance when it was greater than50%.. Pearson correlation analysis wasused for correlation analysis between indexes. Multiple comparisons of themean among groups were by Least-significant Difference (LSD) method. P<0.05was considered statistically significant.Results1、ROC Curve showed that all bilateral common carotid artery elasticity indicesfor CAD had larger than50%area; the area under the curve of each parameterwas greater than50%. The area under the curve was greater on left commoncarotid artery than on the right. Area under the curve of bilateral pulse wave velocity (PWV), arterial coefficient (DC) and compliance coefficient (CC),stiffness parameter(α), stiffness parameter(β), was greater than that ofintima-media thickness (IMT).2、 Significant correlation between elastic parameters-PWV、α、β、DC and CCwas detected (P <0.01).With the increase of the severity of coronary arteriallesions,PWV、α、β increased, DC and CC decreased.. Statistical difference wasfound in these parameters between group A and D (P <0.05), but not betweengroup A and B as well as group C and D.Conclusions1、Carotid arterial IMT and carotid elastic parameters of PWV、α、β、DC、CC had predictive value for coronary heart disease to a certain degree. Closerrelationship had been found between CAD and left common carotid arterial IMTand stiffness parameters than that between CAD and IMT.2、There was certain correlation between the value of carotid artery elasticparameters and the severity of the coronary artery lesions. Ultrasound RF-datatechnique could be considered as one of the non-invasive diagnostic modalitiesin evaluating arterial stiffness in patients with coronary artery diseases.