INTRODUCTION
Intrauterine growth restriction (IUGR) due to placental insufficiency is
predominantly a vascular disorder. It is associated with adverse short
term and long term outcomes [1, 2, and 3]. Fetal
well being tests and indices could be roughly classified as chronic and
acute. Chronic indices (abnormal doppler flow in umbilical artery(UA) or
middle cerebral artery(MCA) become progressively abnormal due to
increasing hypoxemia or hypoxia while acute indices(reversal in ductus
venosus (DV) represent severe fetal hypoxia and metabolic acidosis and
usually precede fetal death in few days . Doppler examination of the
umbilical artery (UA) and the middle cerebral artery (MCA) have proved
to be good predictors of adverse perinatal outcome. However, because the
risks of iatrogenic prematurity are very high before 32 weeks’
gestation, further doppler parameters are needed to assess fetal
compromise. Venous Doppler patterns together with gestational age (GA)
at delivery have been advocated as the best predictors of adverse
perinatal outcome in IUGR fetuses [4] however are
too late and represent the failed fetal defence mechanism against
hypoxia [5]. Thus there is a gap of few days to
weeks between these early and late signs during which new parameters are
needed to document the progression of fetal deterioration in more better
and accurate way. This will help to identify those fetuses whose defence
mechanism against severe hypoxia and acidemia are about to fail but yet
not failed.
Aortic isthmus blood flow pattern reflects the balance between both
ventricular outputs and the existence of differences in the impedance in
either vascular system [6]. Its role as a short
term marker of adverse perinatal outcome [7] and a
long-term predictor of neurodevelopmental outcome [8,
9] have been proposed. Abnormal AoI impedance indices occur prior to
cardiac decompensation [10]. Retrograde flow in
aortic isthmus occurs commonly after the abnormal flow in the umbilical
artery and before abnormal ductus venosus flow .Thus the aim of this
study was to evaluate the association between AoI doppler changes and
adverse perinatal outcome in growth-restricted fetuses and
neurodevelopemental outcome between 2-4yrs of age and to find out
whether can we use retrograde flow in aortic isthmus as an additional
trigger to deliver growth restricted fetuses between 30-34 weeks of
gestation where yet there is a dilemma between continuing the
surveillance vs. delivering prematurely due to lack availability of
clear indicators .