Study Of Transthoracic And Transesophageal Echocardio-graphy In Application Of Transcatheter Aortic Valve Replacement

Background:As the population ages and aortic stenosis due to valvular degeneration becomes more common. Although surgical valve replacemet is an effective treament, which can remove valve disease and improve the quality of life in patients with aortic stenosis. But some patients with severe aortic stenosis can’t afford surgical treatment because of old age and a variety of complications. With the continuous improvement and development of interventional techniques, percutaneous transcatheter aortic valvuloplasty and implantation began to be used in clinical. In2002, Doctor Cribier completed the first transcatheter aortic valve replacement(TAVR) in adults, therefore,which add a new, effective and viable therapeutic option for patients with aortic stenosis. The technology could benefit a large patient population, but if it could be carried out in domestic, many aspects such as the development of the valve, the selection of cases and operation skills need to be continuous improved and researched. This article study the structure and function of aortic valve before,during and after TAVR using ultrasonic diagnostic techniques, in order to ensure the safety and effectiveness of TAVRObjective:To evaluate the role of echo and determine the evaluation of the indexes of outcomes during TAVR, and to provide a more accurate and comprehensive imaging data for the launching of the new clinical technology.Methods:(1) study of TAVR in animal experiments:10goats, pre-operation:The structure and function of aortic valve before and after TAVR observed and measured in views of long-axis and short-axis of left ventricle and four-chamer of TTE, such as aortic annulus diameter,left ventricular volume,left ventricular ejection fraction;Postoperation:following-up observation, such as the position, function and paravalvular leakage of the prosthetic heart valve(HV);(2)the method of measuring aortic annulus diameter was studied by TEE:TTE, in long-axis view of the aorta, the diameter of aortic annulus was measured; Annulus diameter was measured in views of midesophageal, the three-chamber, long-axis of aorta in2D-TEE; The aortic annulus diameter was obtained from the inner edge to inner edge during systolic of cardiac cycle;RT3D-TEE, full-volume imaging was aquired by3D-TEE. The data measured from images was analyzed offline using quantification software (QLAB); the results was analyzed by Paried t-test.(3) Five patients with severe aortic stenosis undergo TAVR:TTE was used to assess the structure and function of aortic valve before operation. In order to determine the appropriate model of prosthetic heart valve (PHV). Intraoperation,after anesthesia,TEE was used to measure the related indicators of aortic valve of the patient again, the patient was monitored in real time and TEE was used to observe the function of PHV positioned, such as paravalvular leakage, the degree of paravalvular leakage and the maximum blood flow velocity of PHV. Postoperation:the patients were followed up6-12months, including position, function, paravalvular leakage and regurgitation of the PHV By TTE and evaluated the quality of life in comprehensively of this group after TAVR.Results:(1) study of TAVR in animal experiments:Preoperation LVV (34.33±2.25ml), EF (71.17±4.79%), velocity of aortic valve(128±6.7cm/s) were measured by TTE;Postoperation LVV (35.67±4.32ml),EF:(75.1+2.07%), velocity of PHV:(167.5±18.2cm/s). Tthe goats were followed up from7days to1year, we observed that opening and closing of PHV was effective.(2) the imaging of aortic annulus diameter of the adults in TEE is better than in TTE; The results of mean diameter of aortic annulus measured by:2D-TTE:21.7±3mm,2D-TEE22.6±2.8mm,3D-TEE22.3±2.9mm. The differences of annulus measurements were significant (2D-TTE vs2D-TEE r=0.83, p<0.05,2D-TEE vs3D-TEE r=0.86, p<0.05,2D-TTE vs3D-TEE r=0.79, p<0.05; there was a high agreement found between2D-TEE and3D-TEE.(3) The role of echocardiography was studied in TAVR:Five patients with severe aortic stenosis were performed TAVR successfully. Five patients were followed up from5months to one year, the paravalvular leakage and regurgitation of the PHV were mild. The physiological condition and physical strengh of five patients compared with those of preoperation were improved.Conclusions:(1) Echocardiography techology was studied in animal experiments for TAVR, the methods was feasible and reliable.(2)2D/3D ultrasound diagnostic technology has a good correlation in measuring the diameter of aortic annulus,TEE is better in observation and measurements of valves. Echocardiography plays an important role in TAVR, which was used to diagnose pre-operation, to guide selection suitable sizing of PHV, to monitor the position of PHV and associated complications, to follow up the outcomes of patients after post-operation.