CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 4, May 2013
130
AFRICA
Cardiovascular haemodynamics in pre-eclampsia using
brain naturetic peptide and tissue Doppler studies
S FAYERS, J MOODLEY, DP NAIDOO
Abstract
Aim:
To determine early haemodynamic changes in pre-
eclampsia (PE) using tissue Doppler echocardiography and
brain natriuretic peptide (BNP), and to relate these changes
to obstetric outcomes.
Methods:
Consenting primigravidae patients in the third
trimester of pregnancy were included in the study, which
was carried out in a large regional hospital in Durban, South
Africa; 115 primigravidae (52 pre-eclamptics and 63 normo-
tensive pregnant patients) attending the maternity unit
including the antenatal clinics at the study site were studied.
The patients, matched for maternal and gestational age,
were examined during pregnancy and within the puerperi-
um. Transthoracic echocardiography (TTE), tissue Doppler
imaging (TDI), umbilical artery Doppler and laboratory
investigations were performed.
Results:
BNP levels were significantly increased in the
antepartum period [23.8 (2–184.1) vs 6.0 (0.5–45.2) pmol/l;
p
<
0.0001] and during labour [15.0 (1.8–206.4) vs 8.7 (1.9–24.8)
pmol/l;
p
<
0.01] in the pre-eclamptic group compared to the
normotensive controls. In the postpartum period, mean BNP
levels were 4.2 (1.7–51.4) and 5.95 (2.2–38.7) pmol/l in the pre-
eclamptic and normotensive groups, respectively (
p
>
0.05).
Tissue Doppler E
m
/E
a
ratios were elevated in the pre-eclamp-
tic compared to the normotensive group (11.02
±
5.6 vs 9.16
±
2.6;
p
<
0.05). Mean left atrial size was larger (38 mm) in the
pre-eclamptic group than in the normotensive group (35 mm)
but this difference was not significant (
p
>
0.05).
The umbilical artery resistance index was significantly
higher in the pre-eclamptic group compared to the normo-
tensive group (0.68
±
0.06 vs 0.63
±
0.05;
p
<
0.001). There
was an increased rate of Caesarean sections performed in
the pre-eclamptic group (
n
=
24) compared to the normo-
tensive group (
n
=
18;
p
<
0.001). There were two stillbirths
in the pre-eclamptic group and none in the normotensive
group. As expected, birth weight (2.6
±
0.8 kg vs 3.14
±
0.42 kg;
p
<
0.0001) was lower in the pre-eclamptic group
compared to the normotensive group.
Conclusion:
In pregnancies complicated by pre-eclampsia,
BNP levels were increased in comparison to normotensive
pregnancies and this was accompanied by early changes in
left ventricular diastolic function as determined by the tissue
Doppler E
m
/E
a
ratios. These changes reverted to baseline
values, as indicated by return of BNP levels in the pre-eclamp-
tic group to levels seen in the normotensive group. These
changes were associated with an increased Caesarean section
rate and lower birth weights in pre-eclamptic mothers.
Keywords:
pre-eclampsia, brain natriuretic peptide, tissue
Doppler, echocardiography
Submitted 24/5/12, accepted 17/4/13
Cardiovasc
J Afr
2013;
24
: 130–136
DOI: 10.5830/CVJA-2013-023
Hypertensive disorders of pregnancy complicate approximately
10–16% of pregnancies and constitute one of the leading
causes of maternal, foetal and neonatal morbidity and mortality
worldwide,
1,2
particularly in low- and middle-income countries.
3
Most, if not all of the morbidity and mortality in hypertensive
disorders of pregnancy arise from pre-eclampia (PE) and its
complications.
4
Pre-eclampsia arises when expression of pro-inflammatory,
anti-angiogenic and angiogenic factors lead to a systemic
endothelial cell dysfunction with exaggerated inflammatory
and vasoconstrictor responses.
5,6
Vasoactive hormones play an
important role in the pathogenesis of PE, linking placental
hypoperfusion with hypertension, systemic disease and
proteinuria.
Until recently most of the non-invasive studies of the
haemodynamic changes of PE have employed two-dimensional
echocardiography to measure cardiac dimensions and systolic
function. Until the advent of tissue Doppler imaging (TDI), there
have been few sensitive echocardiographic measures of changes
in cardiac filling pressure.
Since vasoconstriction and volume retention characterise PE,
it is possible that TDI studies and biomarkers of cardiac stress
may be useful in detecting early haemodynamic changes in PE.
To date, several different biophysical and biochemical markers
have been investigated. These include sflt-1, VEGF, soluble
endoglin, P-selectin and PP-13, which reflect the pathogenesis
of PE,
7,8
and more recently, haemodynamic changes have been
documented with brain (or B-type) natriuretic peptide (BNP).
9
Measurement of both BNP and NT-proBNP have been
shown to be sensitive markers for the detection of mild systolic
or diastolic heart failure or asymptomatic left ventricular
dysfunction,
10,11
and for the diagnosis of congestive heart failure
in patients with dyspnoea in an acute-care setting.
12
Recent
studies suggest that BNP levels are elevated in pre-eclamptics.
13-16
We hypothesised that there may be alterations in the BNP
levels associated with pre-eclampsia in response to changes in
cardiac myocyte stretch and that this may may reflect pressure/
volume changes in the cardiac ventricles in this unique disorder
of pregnancy. There are no studies that correlate BNP values with
Department of Cardiology, University of KwaZulu-Natal,
Durban, South Africa
DP NAIDOO, FCP (SA) UKZN,
Department of Obstetrics and Gynaecology, University of
KwaZulu-Natal, Durban, South Africa
S FAYERS, FCOG
Womens’ Health and HIV Research Group, University of
KwaZulu-Natal, Durban, South Africa
J MOODLEY, FRCOG,
