CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 4, May 2013
AFRICA
135
for intervention, as these factors are documented indicators of
worsening disease progression in PE. The relationship between
proteinuria and the heart need further evaluation, as well as
its relationship to HIV infection. A significant number of our
patients were HIV infected but there were no significant changes
in the BNP or TDI levels, or even in outcome in these subjects.
In our study, seven pre-eclamptic patients required emergency
care post delivery, in keeping with the association between PE
and adverse pregnancy events. Of the seven pre-eclamptics
who required emergency care, two required ICU admission. An
increased rate of Caesarean sections, lower Apgar scores, lower
birth weight and an increased admission rate to neonatal ICU
has been described in PE.
33
Numerous studies have documented
similar pregnancy sequelae in patients with PE.
32-34
Recently, foetal wellbeing by weekly assessment of umbilical
artery Doppler examinations and biophysical profiles were
investigated by Sezik
et
al
. in patients with pre-eclampsia in
their third trimester.
33
It was found that 38% of patients had an
abnormal Doppler on the last evaluation before delivery. In this
group, significantly higher blood pressures and serum uric acid
levels were recorded, lower platelet counts, higher incidence of
IUGR, lower Apgar scores at five minutes, a higher incidence of
perinatal deaths and higher operative delivery rates.
33
We also found umbilical artery velocity to be more practical
in evaluating the foetus in late pregnancy than uterine artery
Doppler studies, which have been used to predict PE and
IUGR.
30-33
Technical difficulties in obtaining access to uterine
Doppler flow readings precluded the use of this measurement
in our study. The increase in the resistance index on umbilical
Doppler velocimetry is well described,
32,33
and abnormal Doppler
umbilical artery waveforms are a strong predictor of perinatal
mortality and are associated with a poor perinatal outome.
32
Previous studies have shown that BNP levels were elevated in
patients with pre-eclampsia but the numbers have been few and
they have not correlated these changes with TDI.
15,17,24
Limitations of the study
BNP is significantly affected by age, gender, renal function and
obesity. Given its correlation with multiple cardiac variables,
BNP has high sensitivity but low specificity for the detection
of elevated left ventricular filling pressures. In our study this
variability was avoided by selecting primiparous patients who
were of similar age and constituted a fairly homogenous group
of black patients, permitting comparisons to be made.
Also, as mentioned above, most of the changes in BNP that
occurred were within normal ranges for our laboratory. It is
likely that BNP activation would be more pronounced in severe
PE. Furthermore, this study was conducted on patients in the
third trimester. Recruitment earlier in pregnancy might have
shown whether or not BNP could be used as a marker of PE.
Conclusion
This study showed that there were significant differences in BNP
levels during PE and this probably reflects the haemodynamic
changes in this condition. Serum BNP levels were significantly
elevated in pregnancies complicated by PE, particularly in those
with more severe disease. This increase was reflected in elevated
tissue Doppler estimations of LV filling pressure (E/E
a
ratio).
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