1396 THE EFFECTS OF PATENT DUCTUS ARTERIOSUS (PDA) ON PULSATILE FLOW IN THE ANTERIOR CEREBRAL ARTERIES (ACA)

Abstract

The noninvasive measurement of pulsatile flow in the ACA is possible with a transcutaneous Doppler technique in infants with an open anterior fontanel. A pulsatility index (PI), calculated from the systolic and diastolic amplitudes of flow, represents resistance to flow (range 0.0-1.0). The Doppler technique has also been used to diagnose PDA. We have used these techniques to study the relationship between PDA and cerebral blood flow in the ACA. PDA was confirmed by radiological and echocardiographic studies. In an ongoing study, 5 infants (birthweight <1500 g) had increase in PI at the time of development of PDA and decrease in PI to normal after closure of the PDA. PI values (mean ± SD) prior to, during and following closure of the PDA were 0.69 ± 0.03, 0.89 ± 0.04 and 0.69 ± 0.01 respectively (N=0.66 ± 0.06). Serial values of PI in a representative case are shown. Arrow represents therapy for closure of PDA. The above data demonstrate decreased pulsatile flow in the ACA at the time of development of PDA and abrupt return to normal following closure of the PDA. These observations re: rapid fluctuations in cerebral blood flow may have implications for the genesis of ischemic cerebral injury and/or the development of intra-ventricular hemorrhage in the premature infant.