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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 29, No 1, January/February 2018
AFRICA
29
reported by Zanstra
et al.
16
Although our study did not find
associations between diastolic blood pressure and obesity with
diastolic dysfunction, women in the pre-eclamptic group had a
significantly higher BMI and diastolic blood pressure than those
in the control group. Additionally, diastolic dysfunction is also a
risk factor for future death.
The Olmsted study described the predictive significance
of left ventricular diastolic dysfunction using multivariable-
adjusted analyses.
19
The hazard ratio for all-cause mortality
was 8.31 (
p
<
0.001) for mild diastolic dysfunction and 10.17
for moderate to severe diastolic dysfunction (
p
<
0.001). At
one year post-delivery, diastolic dysfunction was present in
11.5% of women with pre-eclampsia, in 22.7% of women
with early-onset pre-eclampsia and in 1.9% of women whose
pre-eclampsia developed after 34 weeks. Women with early-onset
pre-eclampsia requiring delivery prior to 34 weeks, irrespective
of the presence of chronic hypertension, were at risk of
developing diastolic dysfunction at one year post-delivery.
Chronic hypertension, therefore, was not an additional risk
factor for diastolic dysfunction at one year in women with early-
onset pre-eclampsia.
This study found that early-onset pre-eclampsia was a risk
factor for diastolic dysfunction, while women who developed
pre-eclampsia after 34 weeks had a risk similar to that of low-risk
parous women (RR 3.41, 95% CI: 1.11–10.5,
p
=
0.04). This may
be explained by the proposed differences in pathophysiology
between early- and late-onset pre-eclampsia.
Redman
et al.
have suggested that pre-eclampsia could
be the result of intrinsic or extrinsic placental causes.
20
In
early-onset pre-eclampsia, factors extrinsic to the placenta
affect the uteroplacental circulation via incomplete spiral artery
remodelling, while in late-onset disease, intrinsic factors affect
the size of the placenta, restricting intervillous perfusion.
20
The placentas of women with early-onset disease differ
significantly from those who develop pre-eclampsia at term.
21
The former group demonstrate placental findings consistent
with insufficiency and vascular lesions, while late-onset disease
is characterised by placental hyperplasia and unimpaired foetal
growth.
21-24
Further evidence suggesting that pre-eclampsia is
more than one disease comes from differences in biochemical
markers, Doppler studies and clinical features of the disease.
25-30
Pre-eclampsia is a known risk factor for future chronic
hypertension. Hypertension and hypertensive heart disease are
one of the key contributors to the burden of non-communicable
cardiovascular disease in Africa. Young African women are bearing
the brunt of this increasing public health problem.
31,32
Several
studies have found that women from sub-Saharan Africa have the
greatest risk of developing pre-eclampsia and eclampsia.
33,34
Nakimuli
et al
., in a study of pre-eclampsia in women
of African ancestry, found that African ancestry was the
second strongest risk factor for pre-eclampsia after chronic
hypertension.
35
African ancestry was also a risk factor for early-
onset pre-eclampsia and poor obstetric outcomes such as foetal
growth restriction and stillbirth.
35
Pregnancy-related deaths from
pre-eclampsia are also three times higher in women of African
ancestry compared with Europeans.
36
Almost 90% of women in
our study were of African origin.
It is estimated that for every woman who dies during
pregnancy or childbirth, 20 others will suffer severe morbidity.
37
Most maternal mortality and morbidity datasets record
information for up to 42 days post-partum. However women
who develop pre-eclampsia during pregnancy, especially those
with early-onset disease, may develop heart failure several years
after pregnancy, resulting in the problem not being adequately
identified and addressed.
The prognosis of women with compromised cardiac function
is poorer than that of men.
18
Women often present with
atypical symptoms, resulting in delayed presentation, delayed
diagnosis and suboptimal care compared to men.
38,39
These
factors highlight the need to identify women at risk of future
cardiovascular disease, with the aim of reducing potential
modifiable risk factors. Blood pressure control, weight loss
and a low-sodium diet are important measures that have
been identified with favourable changes in ventricular diastolic
function.
18
The American Heart Association Guideline on
Lifestyle Management to reduce cardiovascular risk for adults
who would benefit from blood pressure lowering include dietary
modification appropriate to calorie requirements, reduction in
salt intake and three to four sessions of aerobic activity per week
lasting on average 40 minutes per session.
40
This is the first study to evaluate diastolic function in a
pre-eclamptic group of predominantly African population.
Although we did not look at other risk factors for cardiovascular
disease in this population, the study provides valuable information
in identifying a potential group of women at risk of disease at an
early stage. This would provide opportunities for screening and
lifestyle modification.
The strength of this study is that it is one of the first to look
at cardiac diastolic function in an African population where the
rates of hypertension both during and outside of pregnancy were
high. A possible limitation is that most patients were seen for
the first time during pregnancy, with severe acute hypertension.
Only 14.6% of women were known to have chronic hypertension.
It is possible that some women had undiagnosed chronic
hypertension – this is especially likely as the rate of chronic
hypertension postpartum at one year was 54.2%. Some of the
women with undiagnosed chronic hypertension may have had
pre-existing diastolic dysfunction that could have been worsened
by the superimposed pre-eclampsia. A further limitation is that
only a select group of pre-eclamptic women were recruited to
the study.
Conclusion
Women who develop early-onset pre-eclampsia requiring
delivery prior to 34 weeks’ gestation have an increased risk of
cardiac diastolic dysfunction one year after delivery. Diastolic
dysfunction precedes the onset of systolic dysfunction and
Table 3. Cardiac diastolic function at one year
Pre-eclamptic
group,
mean (SD)
Control
group,
mean (SD)
p
-value
Left ventricular ejection
fraction, %
60.54 (7.62)
63.43 (4.88)
0.08
E velocity, m/s
0.98 (0.20)
0.95 (0.14)
0.90
A velocity, m/s
0.70 (0.24)
0.64 (0.05)
0.01
E/A ratio
1.42 (0.39)
1.46 (0.12)
0.74
E-deceleration time (ms)
224.57 (51.00)
225.43 (35.09)
0.08
Lateral e
′
(cm/s)
10.83 (2.86)
11.80 (1.99)
0.02
E/e
′
ratio
10.11 (5.32)
9.96 (2.25)
0.11