The relationship between aortic isthmus Doppler flow and other
Doppler parameters was also assessed and is given in table 4.
There was significant association of retrograde diastolic aortic isthmus
flow with abnormal umbilical artery, abnormal MCA, and abnormal
DVdoppler.12/13(92.3%) cases of retrograde group had abnormal umbilical
artery doppler flow (PI>95th centile or
AREDF). Similarly 12/13(92.3%) cases of retrograde group had abnormal
MCA Doppler flow (PI <2nd centile). 5/13
case of retrograde group had abnormal DV doppler
(>95th centile). 5/7 (71.4%) of abnormal
DV had reverse diastolic flow in the aortic isthmus.
The predictive value of the AoI and other Doppler parameters for an
adverse perinatal outcome were also assessed.The predictive
value of the AoI and other parameters for an adverse perinatal outcome
is given in Table 5.
UA and AoI retrograde Doppler flow patterns and gestational age at
delivery<34 weeks of gestation had the highest positive
likelihood ratios. Abnormal AOI Doppler has 63% sensitivity,
specificity of 87.5%, a good positive predictive value (92.3%) and
positive likelihood ratio of (5) for the prediction of adverse perinatal
outcome.
following equation of multiple regression analysis was used to see the
relationship between Doppler variables and WOG with perinatal outcome -
Perinatal Outcome = 1.685 - (0.134 x UA) - (0.295 x MCA) - (0.097 x DV)
+ (0.164 x AOI) + (0.047 x WOG).
It stated that ,based on standardized coefficient, AOI (0.19) is the
most important factor to extract perinatal outcome followed by WOG
(0.047) .
Prematurity (delivery <34 weeks of gestation) alone has a
sensitivity (70%) and high specificity (93%) and a high positive
likelihood ratio (8.75) as a predictor of adverse perinatal outcome and
overall mortality.
In the retrograde AOI group outcome was also assessed in two subgroups
that is one with normal DV Doppler and another with abnormal DV Doppler
(Table S1). No statistically significant difference was found in these
two subgroups in terms of following parameters.
However, there was higher percentage of RDS (80%vs 38%) and NICU stay
>7 days (100%vs 50%) in retrograde AoI group with
abnormal DV Doppler. Also the only case with NEC had abnormal DVflow
.Also perinatal mortality was higher (25%) in retrograde AoI group with
normal DV.
This subgroup analysis of retrograde AoI group shows that the perinatal
outcome can be adverse even when the DV flow is normal especially in
terms of perinatal mortality.
There were total 18 cases in which weeks of gestation at delivery was
<34 weeks.
Out of these majority (13) cases were delivered prematurely because of
fetal indication that is abnormal Doppler and in only 5 cases maternal
indication was present for delivery <34 weeks.
Analysis of the fetuses with AEDF or REDF in UA with retrograde AoI by
sub grouping in those having normal DV and those with Abnormal DV was
also done, shown in Table no. S2 .
It shows that, the group with normal DV did not require NICU admission
for >7 days, while ¾(75%) cases with abnormal DV required
NICU stay >7 days .There was 1 IUD and 1 NND from the group
with normal DV. while 1 NND from DV abnormal group. So, even with normal
DV Doppler flow the perinatal mortality (40%) was found in AEDF/REDF
with retrograde AOI group with normal DV flow- P value 0.638 ,95% CI
(-0.454-0.754)
Longitudinal changes in Doppler parameters in these IUGR fetuses
are shown in figure 3 The median values for umbilical artery PI
>95th centile ,Absent end diastolic flow
(AEDF),Reverse end diastolic flow (REDF) ,Middle cerebral artery PI
<5th centile ,Retrograde flow in aortic
isthmus and DV Pi > 95 the centile were 8,1,0,7,2 and 0.5
respectively .