Broekhuizen M L, Hogers B, DeRuiter M C, Poelmann R E, Gittenberger-de Groot A C, Wladimiroff J W
Department of Obstetrics and Gynecology, Academic Hospital Rotterdam, Erasmus University, The Netherlands.
Ultrasound Obstet Gynecol. 1999 Jun;13(6):437-45. doi: 10.1046/j.1469-0705.1999.13060437.x.
To obtain insight into hemodynamics during abnormal cardiac development, a chick model was developed recently in which a spectrum of conotruncal anomalies, in combination with abnormal semilunar valves and/or pharyngeal arch artery malformations, was induced through extraembryonic venous obstruction (venous clip) at stage 17 (70-h incubation).
In chick embryos of stage 24 and stage 34 control (n = 8; n = 21) and with venous clip (n = 11; n = 18), we simultaneously measured dorsal flow velocities with a 20-MHz pulsed Doppler velocity meter and dorsal aortic (stage 24) and vitelline artery (stage 34) blood pressures with a servo-null system. After the hemodynamic recordings were collected, all 58 embryos were subjected to morphological examination. The hemodynamic data were correlated with the morphology. Statistical comparison was performed between control and experimental values.
At stage 24, venous clip embryos showed impaired looping. Physiologically, only a decrease in peak acceleration was found in these embryos (p < 0.05). At stage 34, a spectrum of conotruncal malformations was seen, that consisted of a ventricular septal defect in combination with abnormal semilunar valves and/or pharyngeal arch malformations. A dextroposed aorta in combination with a ventricular septal defect was diagnosed as double-outlet right ventricle. Hemodynamically, peak systolic and mean velocities, peak systolic and mean blood flows and stroke volume were increased while the heart rate was reduced after placement of the venous clip (p < 0.05). In both stages, pressure readings showed no statistically significant differences between control and experimental embryos.
Our findings suggest that the hemodynamic changes seen in venous clip embryos reflect the presence of a compensatory mechanism.
为深入了解心脏发育异常期间的血流动力学情况，最近建立了一种鸡胚模型，通过在第17阶段（孵化70小时）对胚外静脉进行阻塞（静脉夹），诱发一系列圆锥动脉干异常，并伴有半月瓣异常和/或咽弓动脉畸形。
在第24阶段和第34阶段的对照鸡胚（n = 8；n = 21）和有静脉夹的鸡胚（n = 11；n = 18）中，我们使用20兆赫脉冲多普勒速度仪同时测量背侧血流速度，并用伺服零位系统测量背主动脉（第24阶段）和卵黄动脉（第34阶段）的血压。收集血流动力学记录后，对所有58个胚胎进行形态学检查。将血流动力学数据与形态学进行关联。对对照值和实验值进行统计学比较。
在第24阶段，有静脉夹的胚胎显示出心脏环化受损。从生理学角度来看，这些胚胎仅出现峰值加速度降低（p < 0.05）。在第34阶段，可见一系列圆锥动脉干畸形，包括室间隔缺损合并半月瓣异常和/或咽弓畸形。右位主动脉合并室间隔缺损被诊断为右心室双出口。血流动力学方面，放置静脉夹后，收缩期峰值和平均速度、收缩期峰值和平均血流量以及每搏输出量增加，而心率降低（p < 0.05）。在两个阶段，对照胚胎和实验胚胎的压力读数均无统计学显著差异。
我们的研究结果表明，有静脉夹的胚胎中观察到的血流动力学变化反映了一种代偿机制的存在。
