Reverse Remodeling Of Left Ventricular Evaluated By Real-time Three-dimensional Echocardiography In Patients With Coronary Artery Bypass Graft

Background and objectiveCoronary atherosclerotic heart disease is called for short coronary artery disease (CAD). The process, by which the coronary arteries become narrowed or completely occluded, is known as atherosclerosis. An imbalance between myocardial functional requirements and the capacity of the coronary vessels to supply sufficient blood flow. CAD is the main reason of death in western countries. On contrast, the incidence rate is lower in our country. However, the incidence of CAD has been going up in recent 20 years. It is very important of treating and evaluating the treatment effectiveness. There were three methods to treat—medication, interventional therapy and surgical therapy according to the specific condition in present. Coronary artery bypass graft (CABG) is the main surgical therapy of ischemic coronary artery disease, which achieved by grafting a section of saphenous vein, internal mammary artery, or other substitute between the aorta and the obstructed coronary artery distal to the obstructive lesion. The results were to increase blood-supply and oxygen supply for ischemic myocardium, to release the symptom of angina pectoris, to improve myocardial function and increase in life span. The methods of evaluating cardiac function by echocardiography in patients implanted cardiac pacemakers have two-dimensional echocardiography (2DE), spectra and colour Doppler echocardiography, acoustic quantitative technique (AQ), Doppler tissue imaging(DTI), real-time three-dimensional echocardiography (RT3DE). RT3DE is a momentous technical breakthrough in ultrasonic imaging field, which could get investigator to research at many aspects, obtain major scope of full volume heart structure stereo data, analyses the size, shape, function of cardiac chambers, supply a sort of feasible, simple new technique for appraise heart global function, segmental function as well as contraction synchronism. Both domestic and abroad scholars have applied RT3DE to quantitatively analyze many heart diseases. To farther study if this method could appraise the change of left ventricle in patients after CABG by RT3DE series indices. However, there are few similar reports domestically and abroadly yet. Therefore, this study measures the left ventricular series indices of the patients with CABG and normal person by RT3DE. The purpose:①To analyze the left ventricular structure, function and synchronism indexes by RT3DE, and approach its remodeling.②To evaluate the reverse remodeling of left ventricular function and synchronism in patients after CABG and clinical application value.③To approach the relations of left ventricular myocardium contractive synchronism and left ventricular end-diastolic left ventricular volume and clinical value in CAD patient.Materials and methodsOur study included 20 patients with three-vessel disease coronary artery disease (CAD) as case group and 20 patients without CAD as normal control group verified by selective coronary angiography. 20 patients (men, mean age 62±7 years) and 20 normal subjects (20 men, mean age 61±8years), the case group was examined by RT3DE before CABG and 1 month after operation. Adopt Philips iE33 colour Doppler ultrasonic instrument, equipped with X3-1 matrix triaxiality probe, frequency 1 -3 MHz. The subjects were taken left lateral position, connected electrocardiography, put triaxiality probe to the apex of heart, after acquired the adaptive apical cardiac four-chamber view imaging, start-up full volume imaging mode , acquired the full volume imaging triaxiality data, sent the pictures to workstation. Opened QLab quantitative analysis software in the workstation and analyzed by 3DQ software, regulated sagittal section and cornoid section was located in the middle of left ventricle, tansverse section layed mitral valve loop level at end-diastole and end-systole separately, after selected five endocardium sample point of four-chamber view mitral valve loop level s interventricular septum and lateral wall, two-chamber view mitral valve loop level s inferior wall and anterior walk cardiac apex, then software traced out dynamic triaxiality endocardium outline automatically. It proceeded to sequential analysis, the left ventricle end-diastole volume(EDV), eject fraction (EF), the 16 segments and those standard deviation(Tmsv16-SD), the maximal difference of time among all 16 segments(Tmsv16-Dif) separately. 17 segments each segment per 0.005 second time-volume database were obtained by QLab software, figured out peak ejection rate (PER= dv/dt min/EDV), peak filling rate (PFR=dv/dt max/EDV), regional peak ejection rate (rPER=r dv/dt min/rEDV), regional peak filling rate (rPFR=rdv/dt max/rEDV).Results1. Compared with control group: End-diastolic left ventricular volume ( EDV) were significantly increased (P<0.01), left ventricular ejection fraction (LVEF), peak ejection rate(PER), peak early filling rate(PFR) in CAD patients were significantly decreased (P<0.01).2. Compared with preoperative: The left ventricular EDV were significantly decreased (P<0.01), EF, PER, PFR and basal regional PER, PFR increased (P<0.01) after operation except inter ventricular septum in CAD group (P>0.05) The left ventricular synchrony index have a significant increase postoperative(P<0.01).3. In patients group, left ventricular EDV correlated closely with Tmsv16-SD ( r =0.751, P<0.01) and Tmsv16-Dif( r =0.655, P<0.01).Conclusion1. Left ventricular remodeling occurred in patients with CAD. There were important values to judge left ventricular remodeling of patients with three-vessel disease using of RT3DE.2. CABG can reverse LV remodeling. The left ventricular reverse remodeling can be evaluated by RT3DE in CAD after CABG.3. There were positive correlation between LVEDV and Tmsvl6-SD, Tmsvl6-Dif, which meant Tmsv16-SD and Tmsv16-Dif could reflect the variance of left ventricular remodeling and reverse remodeling.