Reversal of blood flow in deep cerebral vein in preterm intraventricular hemorrhage: two case reports

BACKGROUND: Intraventricular hemorrhage during the early stage is a major complication in very low birth weight infants. Elevation of venous pressure is one of the contributing factors. The internal cerebral vein receives most of the venous flow from the subependymal germinal matrix, the most common site of origin of intraventricular hemorrhage. Recently, it has been reported that pulsatile or partially interrupted internal cerebral vein waveforms might also be risk factors for intraventricular hemorrhage in extremely low birth weight infants. Here, we report two cases of partially reversed internal cerebral vein flow with intraventricular hemorrhage. There are no published reports documenting this unique flow pattern. CASE PRESENTATION: Between 2013 and 2020, we had in our neonatal intensive care unit two cases of very low birth weight infants (27 and 25 weeks of gestational age) who showed a partially reversed internal cerebral vein waveform pattern, which was recognized as a new blood flow pattern. Their internal cerebral vein flow patterns were continuously flat early after birth. They showed an intraventricular hemorrhage on the unilateral side with partially interrupted internal cerebral vein flow at 31 and 41 hours after birth (27- and 25-week-old neonates, respectively). Consecutively, their internal cerebral vein flow changed to a partially reversed pattern with intraventricular hemorrhage on the contralateral side at 43 and 87 hours after birth (27- and 25-week-old neonates, respectively). Their flow patterns improved by day 7. These partially reversed patterns were equivalent to triphasic venous flow, and the reverse flow corresponded to A- and V-waves. CONCLUSION: In the two cases, the internal cerebral vein flow patterns were normal and flat before intraventricular hemorrhage and changed to a severe flow pattern (partially interrupted or reversed flow) at the same time as the detection of intraventricular hemorrhage. After the development of intraventricular hemorrhage, they improved. These cases indicate that a partially reversed or interrupted internal cerebral vein flow pattern may be derived from central venous pressure elevation and related to intraventricular hemorrhage in very low birth weight infants, however, it is difficult to determine when this flow pattern occurs in relation to intraventricular hemorrhage.