组织多普勒显像对肾上腹主动脉缩窄大鼠心脏形态及舒张功能的研究

目的 采用组织多普勒显像(TDI)评价Lewis大鼠肾上腹主动脉缩窄后心脏的舒张功能变化.方法 选取30只8周龄雄性Lewis大鼠,缩窄其肾上腹主动脉至0.8 mm,造成左室心肌肥厚模型,分别于腹主动脉缩窄术前和术后10 d、20 d、30 d、40 d进行二尖瓣环组织多普勒频谱和常规超声的测量.结果 大鼠心脏前后壁厚度随着随访时间的延长而增加,左室舒张末和收缩末内径也随之增大,左室射血分数(EF)及短轴缩短率(FS)呈下降趋势,以上指标差异均有统计学意义(P＜0.01),大鼠心脏表现为离心性肥厚.二尖瓣环TDI收缩期峰值(Sa)变化趋势不明显,并与EF值相关性较差(r=0.216,P=0.071).无论舒张早期峰值(Ea)、舒张晚期峰值(Aa)和Ea/Aa指标在随访中均无稳定的变化趋势,差异无统计学意义(P＞0.05).而唯有E/Ea一直呈上升趋势,并且经重复测量方差分析,差异有统计学意义(P＜0.001).结论 Lewis肾上腹主动脉缩窄大鼠心脏变化特点主要表现为离心性肥厚,E/Ea值能敏感、稳定地反映大鼠舒张功能的变化过程.

Left ventricular diastolic dysfunction assessment by tissue Doppler imaging in a suprarenal abdominal aortic coarctation model of Lewis rat

Objective To evaluate the left ventricular diastolic dysfunction by tissue Doppler imaging (TDI)in a suprarenal abdominal aortic coarctation model of Lewis rats. Methods Thirty male Lewis rats at age of 8 weeks were used. Myocardial hypertrophy model was obtained by suprarenal abdominal aorta banding with ligation. Mitral annular velocity measurement by TDI and regular two-dimensional echocardiography with M mode were examined at baseline and at 10-,20-,30-and 40-day post banding.Results Compared with baseline,the left ventricular end diastolic and end systolic wall thickness and ventricular dimension were progressively increased,while ejection fraction(EF)and fraction shortening(FS)were decreased(P＜0.0 1).The left ventricle demonstrated centrifugal myocardial hypertrophy.Peak myocardial systolic velocity(Sa)at the mitral annulus did not change significantly throughout this study and there was no significant correlation with EF(r=0.216,P=0.071),and peak myocardial early diastolic (Ea),late diastolic(Aa)at the mitral annulus and Ea/Aa indices also were not stable after aortic banding and there were no significant difference in repeated measures at different time(P＞0.05).But the E/Ea wasincreased and the index had a statistically significant difference(P＜0.001).Conclusions The left ventricleshowed centrifugal myocardial hypertrophy in Lewis rats with abdominal aortic banding.E/Ea radio was a sensitive and stable index to evaluate left ventricular diastolic dysfunction.