超声造影对心肌微血管损伤的实验研究

Experimental study of myocardial microvascular injury by contrast-enhanced ultrasound

摘要:

目的探讨超声造影在负荷试验中对心肌微血管损伤机理。方法以40只健康新西兰大白兔作为研究对象,对所有大白兔进行超声造影,根据超声触发形式分为A组、B组、C组和D组,每组10只。A组采用单纯超声触发,B组采用静息超声触发,C组采用0.5 mL/kg剂量负荷超声,D组用0.05 mL/kg剂量负荷超声。比较各组动物心率、心肌依文思蓝漏出量、心肌出血视觉评分及室性期前收缩情况。同时比较各组心肌病理HE染色观察。结果C组、D组心率高于A组、B组(P<0.05);C组、D组心肌依文思蓝含量、心肌出血视觉评分和室性期前收缩频率高于A组、B组(P<0.05),B组心肌出血视觉评分和室性期前收缩频率高于A组(P<0.05);HE染色结果显示,A组心肌细胞无出血点,B组心肌细胞间隙有散在的红细胞,C组和D组均有大量的红细胞,呈连片状,提示C组、D组损伤较为严重。结论在心脏负荷试验过程中,超声造影剂会明显增加心肌微血管损伤风险,减少剂量仍可引起明显损伤,故在临床实践时需加以避免。

Abstract:

【Objective】To investigate the mechanism of myocardial microvascular injury caused by contrast-enhanced ultrasound(CEUS)in stress test.【Methods】Forty healthy New Zealand white rabbits were selected as the research objects.All the rabbits were performed contrast-enhanced ultrasound(CEUS)and divided into group A,group B,group C and group D according to the type of ultrasound trigger,with 10 rabbits in each group.Group A was given ultrasound alone,group B was given resting ultrasound,group C was given 0.5 m L/kg dose load ultrasound,and group D was given 0.05 mL/kg dose load ultrasound.Heart rate,Evans blue leakage,visual score of myocardial hemorrhage and ventricular prephase contraction were compared in each group.At the same time,HE staining of myocardial pathology was compared in each group.【Results】Heart rate of group C and D was significantly higher than that of group A and B(P<0.05).The content of Evans blue in myocardium,visual score of myocardial hemorrhage and frequency of ventricular prephase contraction in groups C and D were significantly higher than those in groups A and B(P<0.05).The visual score of myocardial hemorrhage and frequency of ventricular prephase contraction in group B were significantly higher than those in group A(P<0.05).The results of HE staining showed that there were no bleeding points in myocardium cells of group A,scattered red blood cells in the space between myocardium cells of group B,and a large number of red blood cells in both group C and group D,which showed a patchy pattern,suggesting that the damage of group C and group D was more serious.【Conclusion】Ultrasound contrast agent can significantly increase the risk of myocardial microvascular injury in the course of cardiac stress test,but reducing the dose can still cause obvious injury,so it should be avoided in clinical practice.