Shih J C, Shyu M K, Hunag S F, Jou H J, Su Y N, Hsieh F J
Department of Obstetrics and Gynecology, College of Medicine, National Taiwan University Hospital, Taipei, Taiwan.
Ultrasound Obstet Gynecol. 1999 Dec;14(6):375-9. doi: 10.1046/j.1469-0705.1999.14060375.x.
To investigate interfetal hemodynamics in acardiac twins and the implications for pathogenesis.
A retrospective study.
All acardiac twins involved in this study were identified by B-mode ultrasound at a teaching hospital in Taiwan.
Color Doppler imaging and, in one case, color power angiography were used to assess umbilical blood flow between acardiac twins and their normal co-twins. Placental anastomoses were examined by pathologists after delivery.
In total five sets of acardiac twins and their normal co-twins were enrolled. Autonomous cardiac activity in the form of a contractile pocket was detected in two cases. Analysis of the pattern of the Doppler waveforms in each case enabled us to classify the type of hemodynamics into one of three categories: 'collision-summation', typified by a pattern of cyclic alternations of bidirectional flow; 'twin-pulse', which described the simultaneous recordings of two opposite constant flows with different pulsating rates; and the 'pump in' pattern, which indicated pulsatile flow in the reversed direction towards the acardiac mass. In two cases we detected, we believe for the first time, an artery-to-vein placental anastomosis between the acardiac twin and its co-twin. The nature of the vascular connections were confirmed on pathological follow-up.
Our observations suggest that acardiac twins may be not only the result of but also the cause of placental vascular anastomoses, which may involve either artery-to-artery or artery-to-vein anastomoses.
研究无心畸形双胎的胎儿间血流动力学及其发病机制。
一项回顾性研究。
本研究中所有无心畸形双胎均由台湾一家教学医院的B超检查确诊。
采用彩色多普勒成像，其中1例采用彩色能量血管造影，评估无心畸形双胎与其正常双胎之间的脐血流情况。分娩后病理学家检查胎盘吻合情况。
共纳入5对无心畸形双胎及其正常双胎。2例检测到以收缩袋形式存在的自主心脏活动。分析每例的多普勒波形模式，使我们能够将血流动力学类型分为三类之一：“碰撞-叠加”，以双向血流的周期性交替模式为典型；“双脉冲”，描述同时记录到两个相反的恒定血流，搏动频率不同；以及“泵入”模式，表明向无心畸形胎儿团块的反向搏动血流。在2例中，我们首次检测到无心畸形双胎与其双胎之间存在动静脉胎盘吻合。病理随访证实了血管连接的性质。
我们的观察结果表明，无心畸形双胎可能不仅是胎盘血管吻合的结果，也是其原因，胎盘血管吻合可能涉及动脉-动脉或动脉-静脉吻合。
