实时三维超声心动图在小儿先天性二尖瓣反流机制研究中的应用

Real-time three-dimensional echocardiography in diagnosis and quantitative assessment of congenital mitral regurgitation

目的探讨实时三维超声心动图在小儿先天性二尖瓣反流病变定性诊断及定量测量中的应用价值。方法选取24例先天性二尖瓣反流患儿(病变仅累积二尖瓣,未合并其他心内畸形)及24例正常儿童,应用实时三维超声心动图全面观察二尖瓣装置形态特点,测量二尖瓣装置三维参数包括收缩期二尖瓣环面积(AA1)、舒张期二尖瓣环面积(AA2)、收缩期与舒张期瓣环面积比(T%)、前后组乳头肌距瓣环距离(AL-A、PM-A)、前后组乳头肌间距离(AL-PM)、前后组乳头肌与瓣环中心点夹角(argAL-C-PM)、前后瓣叶活动度(a1、a2)、左室舒张末期容量(LVEDV)、左室收缩末期容量(LVESV)、左室射血分数(LVEF),量化二尖瓣装置定量测量指标,明确先天性二尖瓣反流的确切机制。结果实时三维超声心动图能全面显示二尖瓣装置的整体形态,可显示二尖瓣裂缺,AA1、AA2、AL-A、PM-A、AL-PM、argAL-C-PM、a1、a2、LVEDV、LVESV、LVEF等三维参数两组间差异有统计学意义,提示二尖瓣病变瓣叶裂缺、瓣叶活动度、瓣环大小、乳头肌位置、左室容量等因素共同影响小儿二尖瓣的正常关闭。结论实时三维超声心动图在立体显示小儿二尖瓣病变组织、定量测量二尖瓣装置三维参数、确定先天性二尖瓣病变反流机制方面有极大优势。

Objective To evaluate the value of real-time three-dimensional echocardiography（RT3DE）in the diagnosis of children with congenital mitral regurgitation,and to establish new quantitative parameters for RT3DE mitral annulus,leaflets,papillary muscles,and left ventricle.Methods Twenty-four children with congenital mitral regurgitation（group 1）were recruited in this study and 24 healthy children（group 2）were studied as control.The morphology of the mitral valve was studied with transthoracic RT3DE image.Custom software（QLAB and self-designed Cadio 4D viewer）was used to trace the MV annulus,leaflets,the papillary apparatus,and left ventricular volume from the 3D data sets.Mitral valve annular area in end-systole（AA1）and annular area in end-diastole（AA2）,the ratio of AA1 and AA2（T%）,AL papillary muscle annular distance（AL-A）,PM papillary muscle annular distance（PM-A）,inter-papillary distance（AL-PM）,the anterior leaflet and posterior leaflet tethering angles（a1,a2,argAL-C-PM）,left ventricular volume of end-systole（LVESV）,left ventricular volume of end-diastole（LVEDV）,and left ventricular ejection fraction（LVEF）were measured.Results Morphologically,congenital clefts were detected with RT3DE.Three-dimensional parameters such as AA1,AA2,AL-A,PM-A,AL-PM,argAL-C-PM,LVEDV,and LVESV were significantly increased in group 1 than those in group 2,while parameter a1 and a2 were decreased significantly in group 1 than those in group 2.These changes revealed that factors such as clefts in the valve,activity of the abnormal valve,the size of the mitral valvular ring,location of the papillary muscle,and capacity of the left ventricle all affected normal opening and closing of the mitral valve.Conclusions RT3DE was useful in permitting comprehensive 3D viewing of the cleft in mitral regurgitation and three-dimensional parameters（AA1,AA2,argAL-C-PM,a1,a2,AL-A,PM-A,AL-PM,LVEDV,LVESV）were related to congenital mitral regurgitation in children.It demonstrates advantages in determining the mechanisms of congenital mitral regurgitation.