End-Diastolic Block in Cerebral Circulation May Predict Intraventricular Hemorrhage in Hypotensive Extremely-Low-Birth-Weight Infants

We investigated the association of intracranial arterial end-diastolic block with mean arterial pressure (MAP), patent ductus arteriosus (PDA) and intraventricular hemorrhage (IVH) in infants with birth weights <1000g. End-diastolic block was diagnosed when end-diastolic flow was found to be absent from the Doppler waveforms in cerebral arteries by pulsed Doppler ultrasound examinations. Cranial ultrasonography and pulsed Doppler examination of anterior cerebral and basilar arteries were performed in 55 preterm infants (gestational age range 24-31 wk) one to four times during the first four days of life. Of these, 22 (40%) developed an end-diastolic block at least once (block group); in 33 no block was detected (control group). Echocardiography was performed and MAP recorded concomitantly. The block group infants had significantly lower mean MAPs than the controls and 59% of those had MAP of 30 mm Hg or lower. In the block group, IVH developed more often in infants with MAP <30 mm Hg (46%) than in infants with MAPs >30 mm Hg (0%). However, in the control group IVH developed equally frequently in infants with MAP ≤30 mm Hg (33%) and in infants with MAP >30 mm Hg (30%). PDA was a significant risk factor for IVH. An end-diastolic block in the cerebral circulation, together with a MAP of ≤30 mm Hg or less and the presence of PDA during the first four days of life, might be associated with IVH in extremely-low-birth-weight infants. (E-mail: outi.tammela@uta.fi)