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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 25, No 5, September/October 2014
AFRICA
233
The proposed role of plasma NT pro-brain natriuretic
peptide in assessing cardiac remodelling in hypertensive
African subjects
Dike B Ojji, Lionel H Opie, Sandrine Lecour, Lydia Lacerda, Olusoji M Adeyemi, Karen Sliwa
Abstract
Aim:
Although plasma NT-proBNP differentiates hyperten-
sion (HT) with or without left ventricular hypertrophy (LVH)
from hypertensive heart failure (HHF), most of the published
data are based on studies in Western populations. Also, most
previous studies did not consider left ventricular (LV) diastol-
ic function and right ventricular (RV) function. We therefore
examined the relation between NT-proBNP on LV and RV
remodelling in an African hypertensive cohort.
Methods:
Subjects were subdivided into three groups after
echocardiography: hypertensives without LVH (HT) (
n
=
83);
hypertensives with LVH (HT
+
LVH) (
n
=
50); and those with
hypertensive heart failure (HHF) (
n
=
77).
Results:
Subjects with HHF had significantly higher
NT-proBNP levels compared to the HT
+
LVH group (
p
<
0.0002). NT-proBNP correlated positively with right atrial
area, an indirect measure of RV function.
Conclusions:
NT-proBNP is proposed as a useful biomarker
in differentiating hypertension with or without LVH from
hypertensive heart failure in black hypertensive subjects.
Keywords:
hypertension, cardiac remodeling, left ventricle, right
ventricle, NT-proBNP
Submitted 27/4/14, accepted 18/8/14
Cardiovasc J Afr
2014;
25
: 233–238
www.cvja.co.zaDOI: 10.5830/CVJA-2014-050
Left ventricular hypertrophy (LVH) represents an important
index of pre-clinical disease, and carries incremental prognostic
value beyond that afforded by traditional coronary risk factors.
1
In a large cohort of black persons, LVH proved to be an even
more powerful predictor of mortality than coronary artery
disease and left ventricular ejection fraction (LVEF).
2
Hence
early detection of LVH is very important in the management of
the hypertensive patient.
Electrocardiography can be very useful in assessing LVH,
especially in middle- and low-income countries, because it is
relatively cheap, accessible and not much expertise is required to
operate an electrocardiography machine. Electrocardiographic
criteria for LVH are, however, not very sensitive, while the
alternative more accurate method of echocardiography is
uneconomical, especially in resource-limited countries.
3
Besides
requiring more expertise, the results may not be adequate in all
patients, especially in those with obesity or pulmonary disease.
4
This situation has led to research on the use of biomarkers such
as NT-proBNP and BNP in the detection of the presence of
LVH and monitoring its regression.
5
B-type natriuretic peptide is a cardiac neurohormone secreted
by myocardial cells located on both the atria and ventricles,
mainly by LV myocardial cells in response to volume expansion
and pressure overload.
6,7
Plasma BNP and NT-proBNP levels are
a useful marker of LVH in hypertension, and have also been found
to rise progressively with increasing severity of hypertension,
particularly when ventricular hypertrophy is present.
6
Similarly,
plasma BNP and NT-proBNP levels are useful to discriminate
between patients with regard to cardiac remodelling and could
be considered as a screening tool to select hypertensive patients
eligible for transthoracic echocardiography.
5
NT-proBNP is also
a useful biomarker in differentiating hypertensive subjects with
LVH from those with heart failure.
8,9
Most of the current knowledge and published data on
the use of plasma NT-proBNP in hypertensive LVH and
hypertensive heart failure (HHF) are based on studies in
Europe and the United States of America, with a dearth of
data in black Africans in whom the burden of hypertension
and hypertensive heart disease is very high.
10,11
For example,
the THESUS study, which studied 1 006 acute heart-failure
subjects in nine sub-Saharan African countries, inclusive of
Nigeria, showed that hypertension was the commonest cause of
heart failure, accounting for heart failure in 45.4% of cases.
12
In
addition, most previous studies on this subject never considered
LV diastolic function or RV function, both of which are reported
to be prognostic markers in hypertensive heart failure.
13,14
We
therefore decided to examine the relationship between circulating
NT-proBNP and left and right ventricular remodelling in a black
African hypertensive cohort.
Cardiology Unit, Department of Medicine, University of
Abuja Teaching Hospital, Gwagwalada, Abuja
Dike B Ojji, PhD
Hatter Institute for Cardiovascular Research in Africa, MRC
Inter-Cape Heart Unit, Department of Medicine, Faculty of
Health Sciences, University of Cape Town, South Africa
Dike B Ojji, PhD,
dikeojji@yahoo.co.ukLionel H Opie, DSc
Sandrine Lecour, PhD
Lydia Lacerda, PhD
Karen Sliwa, PhD
Soweto Cardiovascular Research Unit, Faculty of Health
Sciences, University of the Witwatersrand
Karen Sliwa, PhD
Department of Medical Laboratory Sciences, University of
Abuja Teaching Hospital, Gwagwalada, Abuja
Olusoji M Adeyemi, BSc