定量组织多谱勒速度成像评价大鼠冠脉微栓塞后左室收缩功能

Quantitative tissue Doppler velocity imaging in the assessment of left ventricular systolic function after coronary micro-embolization in rat

目的:动态观察大鼠冠脉微栓塞(CME)模型急性期及慢性过程中的定量组织多谱勒速度成像(QTVI),揭示CME发生及随后慢性过程中心功能的变化规律与特征;研究QTVI在评价CME后心功能变化中的应用价值。方法:以SD大鼠为研究对象,用自身血凝块制成的血栓微粒造成心肌内小冠脉栓塞,建立CME模型。24只大鼠随机分成2组:对照组8只、模型组16只。应用VIVID-7超声显像仪分别同步记录模型构建前、构建后1d、1周、4周大鼠CME模型组和对照组2DE、QTVI图像或曲线并进行观察指标的测量分析;QTVI观察指标为各节段心内膜下层心肌、中层心肌、心外膜下层心肌及全层心室壁收缩峰值速度(SPVendo、SPVmid、SPVepi、SPV)。模型构建后4周处死动物取心肌标本,应用显微图像处理系统结合HE染色定量观察心肌组织内微小梗死灶数(Nmmi),结合Sirius-Red染色定量检测心肌组织胶原纤维的含量(Fcf)。结果:对照组除术后4周LVEDD外各项超声测量指标在各阶段均未发生显著性变化,CME模型组各指标在各阶段发生不同程度显著变化:(1)QTVI:前间隔和后壁SPVen-do、SPVmid、SPVepi、SPV在术后1d、1周、4周较术前显著降低(P<0.01～0.001),SPVendo、SPVmid、SPVepi、SPV术后同一阶段降低的相对值大致相同,但变化的绝对值从大到小依次为SPVendo SPVmid SPVepi。(2)病理与超声测值关系:模型组前间隔和后壁LVEF、SPV、分别均与Nmmi和Fcf具有高度相关性(r>0.70,P<0.05～0.01)。结论:大鼠冠脉微栓塞后急性及慢性过程中发生了不均匀穿壁性、进行性心肌收缩功能减退。QTVI可定量测定大鼠冠脉微栓塞后急性及慢性过程中左心室收缩功能变化。

Objective： To determine quantitative tissue Doppler velocity imaging （QTVI） in the assessment of left ventricular systolic function after coronary micro-embolization （CME） in rat. Methods： Coronary micro-embolization models were built using micro-emboli derived from blood clot of rats to embolize tiny coronary artery in 24 SD rats. The 24 rats were divided randomly into group A （n =8） and group B （n = 16） ; systolic peak velocities of different layers in different segments of left ventricular wall including endocardium, mid-myocardium, epicardium and the whole wall （SPVendo, SPVmid, SPVepi, SPV） were measured using GE Vivid 7 ultrasound system before and 1 d, 1 week and 4 weeks after the establishment of CME model in two groups, and two dimensional （2DE） sonography and QTVI were recorded and studied. The rats were sacrificed four weeks after the establishment of CME model, and the hearts were studied ; the number of micro-myocardial infarction （Nmmi） was studied quantitatively with microscopic image processing system combined with HE staining, and the fraction of collagen fiber （Fcf） was studied quantitatively with microscopic image processing system combined with Sirius-Red staining. Results： Parameters studied by ultrasound did not changed significantly except for LVEDD in group A 4 weeks after the establishment of CME model ; parameters studied by ultrasound occurred various changes at different times ： （1） QTVI： SPVendo, SPVmid, SPVepi and SPV in anterior septum and the posterior wall reduced significantly 1 d, 1 week, 4 weeks after the establishment of CME model compared with that before the establishment of CME model （P 〈0.01 -0. 001 ）; the relative reduction of SPVendo, SPVmid, SPVepi and SPV at the same periored was roughly consistent, and the order of absolute reduction was SPVendo SPVmid SPVepi. （2） Correlation between pathology and ultrasound measurements： significant correlation was found between LVEF and SPV of the anterior septum and the posterior wall and Nmmi and Fcf respectively in group B （ r 〉 0.70, P 〈 0.05 - 0.01 ）. Conclusion： After CME, the rat myocardium occurred uneven penetrating mural and progressive myocardial contractile dysfunction at acute and chronic period. QTVI may determine the changes of left ventricular systolic function at acute and chronic period after CME in rat.