Cardiovascular Journal of Africa: Vol 28 No 1 (January/February 2016)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 1, January/February 2017 AFRICA 23
Endothelial dysfunction and arterial stiffness in
pre-eclampsia demonstrated by the EndoPAT method
A Meeme, GAB Buga, M Mammen, A Namugowa
Abstract
Objectives: The EndoPAT method has been used as a non-
invasive method for assessing endothelial function in several
non-pregnant populations. We investigated its possible use in
assessing endothelial dysfunction in pre-eclampsia.
Methods: Two hundred and fifteen participants were recruited
and grouped as pre-eclamptic cases (105) and normotensive
controls (110). Endothelial function and arterial stiffness were
measured as reactive hyperaemia index and augmentation
index, respectively, using the EndoPAT 2000 machine.
Results: The reactive hyperaemia index was significantly lower
in the pre-eclamptic group compared to the normotensive
group ( p < 0.05). Augmentation index on the other hand was
significantly higher in the pre-eclamptic group compared to
the normotensive group (p < 0.0001).
Conclusion: The EndoPAT method demonstrates endothelial
dysfunction and arterial stiffness in pre-eclampsia.
Keywords: EndoPAT, reactive hyperaemia index, arterial stiff-
ness, augmentation index, pre-eclampsia
Submitted 2/2/15, accepted 5/4/16
Published online 19/5/16
Cardiovasc J Afr 2017; 28: 23–29
DOI: 10.5830/CVJA-2016-047
Pre-eclampsia is a pregnancy-specific multisystem disorder
characterised by new-onset hypertension and proteinuria from
20 weeks’ gestation in a previously normotensive pregnant
woman. It is one of the major causes of maternal and perinatal
morbidity and mortality worldwide and more so in developing
countries.1,2
In the complex and intriguing pathogenesis and
pathophysiology of pre-eclampsia, endothelial dysfunction
remains the most agreed-upon central mechanism involved,
leading to clinical manifestations of the syndrome.3 Endothelial
function in pregnancy has been assessed using several methods
in different studies, including direct, indirect, invasive and
non-invasive techniques.4
The most commonly used (gold standard) non-invasive
technique in assessing endothelial function in pregnancy is the
ultrasonography method called flow-mediated dilatation (FMD)
of the brachial artery. The technique measures endothelial
function by inducing reactive hyperaemia (which is based
on nitric oxide production and bioavailability) by temporary
occlusion and measuring the resultant relative increase in blood
vessel diameter. 5-10 This method however is user dependent,
expensive and requires specialised, trained personnel to execute,
and it is not readily available for routine investigational use.
This means there is a need for a technique that is non-invasive,
accurate, affordable and reliable to use either alone or in
combination with other markers in screening patients for risk for
pre-eclampsia.
The EndoPAT method is non-invasive, easy to use, user-
independent and immediate, and provides automatically
calculated results for assessing endothelial function.11 It has been
used rather extensively in recent years for assessing endothelial
dysfunction in non-pregnant subjects.12-15 However, its use in
pregnancy and pre-eclampsia is limited to only a few studies
done in Scotland and Israel. 16,17 No study has reported on its use
in assessing endothelial function in a rural African population.
This study set out to assess pulse-amplitude tonometry (PAT)
using EndoPAT 2000 in normotensive and hypertensive pregnant
women in rural Africa to determine whether it could demonstrate
endothelial dysfunction associated with pre-eclampsia.
Methods
The study was done with approval from the Bio-Ethics
Committee of the Faculty of Health Sciences, Walter Sisulu
University (bioethics clearance certificate No.045/010). It was a
prospective case–control study conducted in Mthatha Hospital
Complex, Eastern Cape, South Africa, between 2010 and 2013.
A total of 215 participants with known HIV status were
recruited into the study; 105 women had pre-eclampsia (cases)
and 110 were normotensive pregnant women (controls).
Selection of cases was based on persistent blood pressure of ≥
140/90 mmHg on two occasions, at least four to six hours apart
or a single reading of ≥ 160/110 mmHg, and proteinuria of
≥ 1+ on at least two random specimens collected at least four
hours apart (or a 24-hour urine protein of ≥ 300 mg/l) from
20 weeks of gestation, as defined by the International Society
for the Study of Hypertension in Pregnancy (ISSHP). Controls
were age-matched (within two to three years) and gestational
age-matched (within two weeks) normotensive pregnant women
attending the antenatal clinic or admitted for other obstetric
conditions other than hypertension or diabetes.
Women with severe hypertension (blood pressure of
≥ 160/110 mmHg) not responding to treatment, imminent
eclampsia, foetal distress, the HELLP syndrome or eclampsia
and other complications requiring immediate intervention were
Department of Human Biology, Walter Sisulu University,
Mthatha, South Africa
A Meeme, MSc, PhD,
M Mammen, MSc, PhD
A Namugowa, MSc, PhD
Department of Obstetrics and Gynaecology, Walter Sisulu
University, Mthatha, South Africa
GAB Buga, MBChB, MMed, PhD