Fetal cerebral vascular impedance is abnormal in left congenital diaphragmatic hernia.
Congenital diaphragmatic hernia (CDH) can cause significant mass effect in the fetal thorax displacing the heart into the opposite hemithorax. In left CDH (L-CDH), this is associated with smaller left-sided cardiac structures and lower 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 pulsatility index (MCA PI), a measure of vascular impedance, in L-CDH and right CDH (R-CDH) versus unaffected fetuses, and the relationship of MCA PI to LVCO. We hypothesized that MCA PI is lower in L-CDH and similar in R-CDH compared to controls. We further hypothesized that MCA PI would be correlated with LVCO.
We identified all fetuses with CDH at UCSF from 2011 to 2018. Fetal echocardiograms and ultrasounds were reviewed. Umbilical artery (UA) and middle cerebral artery (MCA) Dopplers were measured 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. A subset of survivors had data available from neurodevelopmental assessments as measured by the Bayley Scales of Infant Development- 3rd edition. Measurements in CDH fetuses were compared to unaffected, gestational age-matched controls.
A total of 66 fetuses (L-CDH= 53; R-CDH= 11) comprised the study cohort, with 27 unaffected fetuses serving as controls. Mean gestational age at evaluation was similar in all three groups. Compared to controls, fetuses with L-CDH had significantly lower MCA PI z-scores (-1.3, 95% CI: -1.6, -1.0; control: 0.08, 95% CI: -0.5, 0.6, p <0.001), while there was no difference when compared to the R-CDH group. There was a strong positive association between LVCO and MCA PI z-score (p= 0.01). BPD and HC were similar in all three groups. At follow up, mean cognitive and language scores in the CDH group were within one standard deviation of the general population.
MCA PI values are significantly lower in L-CDH fetuses as compared to controls and a lower LVCO was correlated with lower MCA vascular impedance. The neurodevelopmental effect of changes in MCA PI in response to decreased LVCO are unknown, although all survivors that underwent testing in this cohort scored in the normal range. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
cerebral sparing; cerebrovascular resistance; congenital diaphragmatic hernia; middle cerebral artery pulsatility index; neurodevelopmentPMID: 32068925 DOI: 10.1002/uog.21992