自主研制镍钛记忆合金左心耳封堵器封闭左心耳对实验动物左心功能的影响

Transthoracic Doppler evaluation of a self-designed nickel-titanium memory alloy left atrial appendage occluder on left atrial and ventricular function

目的:应用经胸彩色多普勒超声技术评价自主研制的镍钛记忆合金左心耳封堵器封闭左心耳对实验动物猪左心房、左心室功能的影响。方法:实验于2005-09/2006-08在南京医科大学第一附属医院江苏省实验动物中心完成。①实验分组:选用苏钟小型种猪17只,随机分为实验组12只和对照组5只。②实验干预:实验组12只苏钟小型种猪使用自主研制的左心耳封堵器(发明专利号码:200610037789.3,公开号CN1799521,由镍钛合金骨架、多聚四氟乙烯膜和传送连接部分等构成。其外观呈单盘状,封堵器的左心房面呈圆盘状,直接连接放入心耳内的圆柱体结构)行左心耳封堵,对照组5只手术步骤相同而不采用封堵器行左心耳封堵。③实验评估:两组动物分别于术前、术后1周、2周、4周采用经胸超声心动图检查观察心功能的改变,测量左心房内径、最大及最小容积、左房射血分数、左心房搏出量、血流分数等左房功能参数以及左室射血分数、左室短轴缩短率、Tei指数、E/A比值等指标。结果:①实验动物数量分析:在施行左心耳封堵后,1头猪于术中出血过多并出现室颤后死亡,1头猪因封堵器脱入左房,卡在二尖瓣口导致死亡。其余动物封堵效果良好。②两组动物术后1,2,4周左房功能指标各参数与术前比较无明显变化(P>0.05);与术前相比,实验组术后1周、2周左室射血分数、左心室短轴缩短率、E/A比值分别由术前的0.70±0.04、0.39±0.03、1.33±0.28降低至术后1周的0.59±0.05、0.31±0.03、0.95±0.11(P<均0.01)及术后2周的0.62±0.05、0.33±0.05、0.90±0.05(P<均0.01);Tei指数由术前的0.48±0.02增加至术后1周的0.59±0.03(P<0.01)及术后2周的0.58±0.04(P<0.01)。对照组手术前后左室功能指标差异无显著性。结论:自主研制左心耳封堵器可以有效的封堵左心耳;左心耳封堵后短期内对实验动物左房功能无明显影响;封堵后短期内对左心室功能具有短期的减弱,更长期的安全性有待于进一步研究。

AIM： To evaluate the impact of a left atrial appendage occlusion device made from a nickel-titanium memory alloy on the left atnal and ventricular function as evidenced by transthoracic color Doppler. METHODS： The experiment was carried out in the Experimental Animal Center of First Affiliated Hospital of Nanjing Medical University from September 2005 to August 2006. Seventeen Suzhong miniature pigs were selected and randomly assigned to experiment group （n =12） and control group （n =5）. The left atrial appendage ocduder （patent number： 200610037789.3, public number： CN1799521） was composed of a nickel titanium alloy frame with a polytetrafluoroethylene surrounding membrane, and associated deployment apparatus. Its shape was similar to a disc headed stopper, with the left atrical part shaped like a round disc, and the atrial appendage part like a cylinder. The occluder was surgically implanted in the experiment group, while the control group was subjected to a sham procedure without implanting the occluder. Before operation, and one, two and four weeks afterward, the transthoracic echocardiography was used to evaluate the left atrial dimension, eject fraction （LA EF）, flow fraction, LA stroke volume, left ventdcular dimension （LV）, LV EF, fractional shortening （FS）, E-wave velocity/A-wave velocity （E/A）, Tel index etc. RESULTS： （1）After left atrial appendage occlusion, one pig died due to exsanguination and ventricular fibrillation, and another one died because the occluder fell back into the main cavity of LA, and obstructed the mitral orifice; other animals were occluded well. （2）Compared with pre-operation, the left atrial functional parameters of two groups showed no significant difference at one, two and four weeks after operation （P 〉 0.05）. Compared with pre-operation, the LV EF, FS and E/A significantly decreased one and two weeks after operation [pre-operation： （0.70 ± 0.04, 0.39 ± 0.03, 1.33 ± 0.28）; one week： （0.59± 0.05, 0.31±0.03, 0.95± 0.11, P〈 0.01）; two weeks： （0.62±0.05,.0.33 ± 0.05, 0.90 ± 0.05, P〈 0.01）]. Tel index increased significantly postoperatively [pre-operation： （0.48±0.02）; one week： （0.59 ± 0.03, P 〈 0.01 ）; two weeks： （0.58 ± 0.04, P 〈 0.01 ）]. No significant change was found in the left ventricular parameters in the control group before and after the operation. CONCLUSION： The LA appendage occluder effectively blocks the LA appendage without significantly compromising LA function in a short term. However, the LV functional parameters are decreased, so the long-term effects of this occluder require further investigation.