Division of Pediatric Cardiology, Department of Pediatrics, The University of California San Francisco, San Francisco, CA, USA.
Division of Neonatology, Department of Pediatrics, The University of California San Francisco, San Francisco, CA, USA.
Ultrasound Obstet Gynecol. 2021 Mar;57(3):386-391. doi: 10.1002/uog.21992.
Congenital diaphragmatic hernia (CDH) can cause a significant mass effect in the fetal thorax, displacing the heart into the opposite hemithorax. In left-sided CDH (L-CDH), this is associated with smaller left-sided cardiac structures and reduced left-ventricular cardiac output (LVCO). The effect of these physiologic changes on cerebral blood flow is not well understood. We sought to describe the middle cerebral artery (MCA) pulsatility index (PI), a measure of cerebrovascular impedance, in fetuses with L-CDH and those with right-sided CDH (R-CDH) compared with unaffected fetuses, and the relationship between MCA-PI and LVCO. We hypothesized that MCA-PI would be lower in fetuses with L-CDH and similar in those with R-CDH compared to controls, and that MCA-PI would be correlated with LVCO.
We identified all fetuses with CDH evaluated at The University of California San Francisco, San Francisco, CA, USA from 2011 to 2018. Fetal echocardiograms and ultrasound scans were reviewed. Umbilical artery and MCA Doppler examinations were assessed to calculate pulsatility indices. Ventricular outputs were calculated using Doppler-derived stroke volume and fetal heart rate. Lung-to-head ratio (LHR), estimated fetal weight, biparietal diameter (BPD) and head circumference (HC) were obtained from fetal sonograms. Measurements in fetuses with CDH, according to the side of the defect, were compared with those in unaffected, gestational age-matched controls. A subset of CDH survivors had available data on neurodevelopmental outcome, as assessed using the Bayley Scales of Infant Development, 3 edition.
A total of 64 fetuses with CDH (L-CDH, n = 53; R-CDH, n = 11) comprised the study groups, with 27 unaffected fetuses serving as controls. Mean gestational age at evaluation was similar between the three groups. Compared to controls, fetuses with L-CDH had significantly lower LVCO expressed as a percentage of combined cardiac output (CCO) (32%; 95% CI, 29-35% vs 38%; 95% CI, 33-42%; P = 0.04) and lower MCA-PI Z-score (-1.3; 95% CI, -1.7 to -1.0 vs 0.08; 95% CI, -0.5 to 0.6; P < 0.001), while they did not differ between the R-CDH group and controls. There was a strong positive association between LVCO as a percentage of CCO and MCA-PI Z-score in the overall cohort of CDH and control fetuses (P = 0.01). BPD and HC were similar between the three groups. At neurodevelopmental follow-up, mean cognitive, motor and language scores in the CDH group were within 1 SD of those in the general population.
MCA-PI values are significantly lower in fetuses with L-CDH as compared to controls, and lower LVCO was correlated with lower MCA vascular impedance. The neurodevelopmental effect of changes in MCA-PI in response to decreased LVCO is unknown, although, on average, CDH survivors had neurodevelopmental scores in the normal range. This may reflect a fetal compensatory mechanism in response to diminished antegrade cerebral blood flow. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.
先天性膈疝（CDH）可在胎儿胸腔中产生显著的肿块效应，将心脏推向对侧胸腔。在左侧 CDH（L-CDH）中，这与较小的左侧心脏结构和左心室心输出量（LVCO）减少有关。这些生理变化对脑血流的影响尚不清楚。我们旨在描述大脑中动脉（MCA）搏动指数（PI），即脑血管阻抗的一种衡量标准，在 L-CDH 胎儿与 R-CDH 胎儿（R-CDH）与正常胎儿进行比较，并探讨 MCA-PI 与 LVCO 之间的关系。我们假设 L-CDH 胎儿的 MCA-PI 会更低，而 R-CDH 胎儿的 MCA-PI 与对照组相似，并且 MCA-PI 与 LVCO 相关。
我们确定了 2011 年至 2018 年期间在美国加利福尼亚大学旧金山分校（旧金山，CA）接受 CDH 评估的所有胎儿。对胎儿超声心动图和超声扫描进行了回顾。评估脐动脉和 MCA 多普勒检查以计算搏动指数。使用多普勒衍生的每搏输出量和胎儿心率计算心室输出量。通过胎儿超声获得肺与头比（LHR）、估计胎儿体重、双顶径（BPD）和头围（HC）。根据缺陷的侧别，将 CDH 胎儿的测量值与无缺陷、胎龄匹配的对照组进行比较。CDH 幸存者中有一部分具有神经发育结局的数据，使用贝利婴幼儿发育量表，第三版进行评估。
总共纳入了 64 例 CDH 胎儿（L-CDH，n=53；R-CDH，n=11）作为研究组，其中 27 例无缺陷胎儿作为对照组。三组的平均胎龄评估相似。与对照组相比，L-CDH 胎儿的 LVCO 作为心输出量（CO）的百分比明显降低（32%；95%CI，29-35% vs 38%；95%CI，33-42%；P=0.04），MCA-PI Z 评分也降低（-1.3；95%CI，-1.7 至-1.0 vs 0.08；95%CI，-0.5 至 0.6；P<0.001），而 R-CDH 组与对照组之间没有差异。在 CDH 和对照组胎儿的总队列中，LVCO 作为 CO 的百分比与 MCA-PI Z 评分之间存在很强的正相关（P=0.01）。三组的 BPD 和 HC 相似。在神经发育随访中，CDH 组的平均认知、运动和语言评分均在一般人群的 1 个标准差范围内。
与对照组相比，L-CDH 胎儿的 MCA-PI 值明显降低，较低的 LVCO 与较低的 MCA 血管阻抗相关。MCA-PI 变化对 LVCO 降低的神经发育影响尚不清楚，尽管 CDH 幸存者的平均神经发育评分在正常范围内。这可能反映了胎儿对前向脑血流减少的代偿机制。
