胎儿超声心动图对正常胎儿主动脉峡部血流频谱分析的研究

Study on flow states in normal fetal aortic isthmus by echocardiography

目的应用胎儿超声心动图对正常胎儿主动脉峡部进行血流频谱分析，探求不同孕周主动脉峡部的血流特点。方法选取我院胎儿心脏病母胎医学研究重点实验室的多中心协作数据，孕龄在22-38周且随访结果为正常的胎儿265例，分析主动脉峡部内径、血流速度及逆向血流持续时间、搏动指数、阻力指数等超声参数，并分析这些参数与孕龄的相关性。结果正常胎儿主动脉峡部收缩末期存在短暂的反向血流现象，中孕早期（P50=25．55周）为折线型，中孕晚期至晚孕早期（P50=30．10周）为凹陷型，晚孕晚期（P50=35．40周）为逆向型。主动脉峡部内径、收缩末期血流速度与孕周呈良好的直线相关（分别R=0．726，0．786，P〈0．05），收缩末期持续时间与孕周呈较好的直线相关（R=0．518，P〈0．05）。结论正常胎儿主动脉峡部的血流特点为收缩末期可出现短暂的逆向流动，且随孕龄的增长而逐步显著，可为鉴别诊断异常血流状态提供一定的参考信息。

Objective To explore blood flow characteristics of normal fetal aortic isthmus （AoI） in different gestational age by fetal echocardiography. Methods Two hundred and sixty-five normal fetuses were enrolled in the study from August 2015 to July 2016. The mean gestational age was （29.35 ± 4.50） weeks, The AoI inner diameter（D）, systolic and diasctolic as well as end-systolic velocities （v）, end-systolic duration time（t）, pulsatility index（PI）, resistance index （RI） were measured. The relationship between these parameters and gestational age was plotted by linear regression. Results In normal fetues, there was a short reverse flow at the end of systole and these states could be classified into three categories by gestational weeks（GW）：（1） line-like wave （P50 = 25.55 GW）;（2） incisura wave （P50 = 30.10 GW）;（3） reverse flow （P50 = 35.40 GW）. There were good correlation between end systolic v and gestational age （R = 0.786, P 〈0.05）,as well as D and gestational age（ R = 0.726, P 〈0.05）. The correlation between end-systolic t and gestional age was moderate （ R = 0. 518, P 〈0.05）. Conclusions A short reverse flow can be the characteristics of normal fetal aortic isthmus, and the end systolic flow increases significantly with the gestational age. These characteristics can provide differential information for abnormal blood flow states.