VVI及对比超声评价犬冠状动脉狭窄时心肌灌注和舒张功能的关系

目的 应用速度向量成像(VVI)结合心肌声学造影(MCE)评价犬冠状动脉狭窄静息和负荷状态下心肌组织灌注和舒张功能的关系.方法 制作不同程度冠状动脉(前降支)狭窄模型8只,在冠状动脉狭窄前后于静息和多巴酚丁胺注射达峰值剂量时,取左心室短轴图像行VVI分析,并行MCE测量心肌血流量(A·β值)和短轴圆周方向上的舒张期峰值应变率(SRdia),评价二者之间的相关性.结果 静息状态下,冠状动脉轻、中度狭窄时,供血区SRdia和A·β值与正常区差异无统计学意义;重度狭窄时,供血区SRdia和A·β值均低于正常区(P<0.05).多巴酚丁胺负荷下,轻、中度冠状动脉狭窄时,供血区SRdia和A·β值即低于正常区(P<0.05);重度狭窄时,缺血区SRdia和A·β值较正常区降低得更加明显(P<0.05).无论静息还是负荷状态下,SRdia和A·β间均呈正相关(r静息=0.57,r负荷=0.72,P<0.01).结论 VVI技术能够用于评价短轴心肌节段舒张功能,且能在一定程度上反映心肌血流灌注的变化情况.

Velocity vector imaging combined with contrast echocardiography in evaluation of relationship between myocardial perfusion and diastolic function in dog models of coronary artery stenosis

Objective To evaluate the relationship between myocardial perfusion and diastolic function with velocity vector imaging (VVI) combined with myocardial contrast echocardiography (MCE) in dog models of coronary artery stenosis at rest and stress. Methods Different stenoses in anterior descending branch were made in 8 dogs. Before and after coronary artery stenosis, VVI evaluation was made on short axis image, then MCE were performed in the left ventricular mastoid muscle section at rest and in the peak dose of dobutamine. The myocardial blood flow A·β value and peak diastolic strain rate (SR_(dia)) on the direction of the circumference of the short view were measured, and the relationship between them was analyzed. Results At rest, no significant difference of A·β value nor SR_(dia) was found between the stenotic bed and normal bed when coronary stenosis was mild or moderate. However, A·β value and SR_(dia) of the stenotic bed were smaller than those in the normal bed when coronary stenosis was severe (P<0.05). At dobutamine stress, A·β value and SR_(dia) of the stenotic bed were already less than those in the normal bed when coronary stenosis was mild or moderate. A·β values and SR_(dia) of the stenotic bed decreased further compared to the normal bed (P<0.05) when coronary artery was severe. At both rest and stress, the standard A·β value was strongly correlated with SR_(dia) (r_(rest)=0.57,r_(stress)=0.72,P<0.01). Conclusion VVI can not only evaluate the diastolic function of myocardial segments on the short axis view, but also reflect changes of myocardial perfusion to a certain extent.