超声引导下急性缺血性左室舒张功能障碍并二尖瓣反流犬模型的构建

Establishing the model of acute ischaemic left heart failure with mitral regurgitation in beagles

目的探讨超声引导下急性缺血性左室舒张功能障碍并二尖瓣反流犬模型的构建。方法 (1)二尖瓣反流模型的建立:比格犬15条,经左颈动脉穿刺并送入动脉鞘。在超声引导下,将动脉鞘送入左室,鞘前端置于二尖瓣前叶边缘,经动脉鞘将内镜活体取样钳置于二尖瓣尖下,钳断二尖瓣腱索。经胸心脏超声证实存在二尖瓣反流。(2)急性缺血性左室舒张功能障碍模型的建立:在超声引导下,外撤动脉鞘使其前端置于左冠状动脉窦内,间歇多次注射塑料微球于左冠状动脉窦内,微栓塞冠状动脉,左室舒张末压升高≥5 mm Hg定义为建模成功,形成急性缺血性舒张功能不全。结果 (1)15条比格犬制作二尖瓣反流模型全部成功;14条犬形成中度二尖瓣反流,1条比格犬造成重度二尖瓣反流。多普勒频谱测量二尖瓣反流,V max为(483.0±1.1)m/s,PG max为(162.7±1.8)mm Hg。(2)15条二尖瓣反流比格犬进行急性缺血左室舒张功能障碍模型构建,成功12条,3条未成功。12条成功模型的左室舒张末压升高、最大左室压力下降速率(-d P/dtmax)降低、左室松弛时间常数(Tau)延长。结论超声引导下,经颈动脉鞘管送入活检钳钳夹二尖瓣腱索制造二尖瓣反流(MR)、间歇多次注射微球入左冠状动脉窦构建急性缺血性舒张功能障碍比格犬模型,具有操作简便、方法可靠、成功率高等优点。

Objective To establish the model of acute ischaemic left heart failure with mitral regurgitation in beagles.Methods（ 1） The construction of mitral regurgitation（ MR） animal model： a catheter was introduced into left ventricle through the carotid artery in 15 experiment beagles,then a biopsy clamp was put into the mitral valve nearby through the catheterization and chordae tendineae was pinched under the guidance of echo in order to construct mitral regurgitation.（ 2） The construction of acute ischaemic left ventricular（ LV） diastolic heart failure： 15 beagles with MR were further processed with coronary microembolization by microspheres repeatedly. Results（ 1） All mitral regurgitation models were successfully produced. The chordae tendineaes were broken in thirteen dogs,causing moderate MR. One dog with natural mild MR was with broken chordae tendineae. Continuous wave Doppler showed that the MR peak velocity was（ 483 ± 1. 12） cm / s,the maximun pressure gradient was（ 162. 7 ± 1. 8） mmHg.（ 2） 12 models of acute ischaemic left diastolic heart failure with mitral regurgitation were established. Left ventricular end-diastolic pressure emitting equal or greater than 5 mmHg was defined as model successful. The left ventricular end-diastolic pressure（ LVEDP）,-dP / dtmax,Tau-c in successful model were increased significantly（ P〈0. 05）. Conclusions This method is safe,feasible and easily successful in constructing the MR animal model under the guidance of transthoracic echocardiography. Coronary microembolization with microspheres is a sueeessfull way for establishing the acute ischaemic left diastolic heart failure.