Lam Y H, Tang M H, Tse H Y
Department of Obstetrics and Gynaecology, University of Hong Kong, Tsan Yuk Hospital, Hong Kong, China.
Ultrasound Obstet Gynecol. 2001 Jan;17(1):30-3. doi: 10.1046/j.1469-0705.2001.00315.x.
Fetuses affected by homozygous alpha-thalassemia-1 are anemic from the first trimester of pregnancy. We investigated ductus venosus Doppler velocimetry in these affected fetuses at 12-13 weeks of gestation.
Prospective observational study.
Women referred for the prenatal diagnosis of homozygous alpha-thalassemia-1 before 14 weeks of gestation.
All fetuses underwent pulsed Doppler investigations following color flow mapping at 12 or 13 weeks of gestation. Homozygous alpha-thalassemia-1 was diagnosed by DNA or hemoglobin study. The ductus venosus Doppler indices--Vmax (peak velocity during ventricular systole), Vmin (minimum forward velocity during atrial systole), TAMX (time-averaged maximum velocity), PIV (pulsatility index for veins, Vmax-Vmin/TAMX), PLI (preload index, Vmax-Vmin/Vmax) and Vmax/Vmin ratio--were compared between the affected fetuses and fetuses unaffected by homozygous alpha-thalassemia-1.
Between June 1998 and October 1999, 102 eligible women were recruited. Fetal ductus venosus Doppler study was successful in 96 pregnancies (94%). Of these, 20 fetuses were affected by homozygous alpha-thalassemia-1. None of them showed hydropic changes at the time of Doppler study. The affected fetuses had significantly higher ducts venosus Vmax (30% increase), Vmin (50% increase) and TAMX (20% increase) and significantly lower Vmax/Vmin ratio, PIV and PLI values.
Fetuses affected by homozygous alpha-thalassemia-1 at 12-13 weeks had increased forward flow velocities in the ductus venosus throughout the cardiac cycle. The increase of venous return is consistent with our previous report of cardiac dilatation and an increase of cardiac output in the affected fetuses at this stage as a compensatory mechanism for anemia and hypoxia. However, extensive overlap of the ductus venosus Doppler indices between affected and unaffected fetuses precludes its use in predicting anemia at 12-13 weeks.
受纯合子α地中海贫血-1影响的胎儿从妊娠早期就出现贫血。我们在妊娠12 - 13周时对这些受影响的胎儿进行了静脉导管多普勒测速研究。
前瞻性观察性研究。
妊娠14周前因纯合子α地中海贫血-1的产前诊断而转诊的女性。
所有胎儿在妊娠12周或13周时进行彩色血流图检查后接受脉冲多普勒检查。通过DNA或血红蛋白研究诊断纯合子α地中海贫血-1。比较受影响胎儿与未受纯合子α地中海贫血-1影响的胎儿的静脉导管多普勒指标——Vmax（心室收缩期峰值速度）、Vmin（心房收缩期最小前向速度）、TAMX（时间平均最大速度）、PIV（静脉搏动指数，Vmax - Vmin/TAMX）、PLI（前负荷指数，Vmax - Vmin/Vmax）和Vmax/Vmin比值。
1998年6月至1999年10月，招募了102名符合条件的女性。96例妊娠（94%）成功进行了胎儿静脉导管多普勒研究。其中，20例胎儿受纯合子α地中海贫血-1影响。在进行多普勒研究时，它们均未出现水肿变化。受影响的胎儿静脉导管Vmax显著更高（增加30%）、Vmin显著更高（增加50%）和TAMX显著更高（增加20%），而Vmax/Vmin比值、PIV和PLI值显著更低。
妊娠12 - 13周受纯合子α地中海贫血-1影响的胎儿在整个心动周期中静脉导管的前向血流速度增加。静脉回流增加与我们之前关于此阶段受影响胎儿心脏扩张和心输出量增加的报告一致，这是对贫血和缺氧的一种代偿机制。然而，受影响胎儿与未受影响胎儿的静脉导管多普勒指标有广泛重叠，这使得其无法用于预测妊娠12 - 13周时的贫血情况。
