SA JOURNAL OF DIABETES & VASCULAR DISEASE
DRUG TRENDS
VOLUME 7 NUMBER 1 • MARCH 2010
41
reviewed a study he had co-authored
studying the role of nitric oxide, a potent
antithrombotic and vasodilator, and how
it could be regulated. ‘Arginine is the sole
precursor to nitric oxide and its administra-
tion has been shown to reduce blood pres-
sure, inhibit atherogenesis and improve
heart failure outcomes and endothelial
function’, he said.
The study investigated the relationship
between plasma arginine and blood pres-
sure in hypertensive black South Africans.
The study found that while fasting arginine
concentrations were often elevated in
these patients, it apparently was not always
available for nitric oxide formation or that
the nitric oxide was degraded and unable
to mediate vasodilatation.
Nonetheless, Dr Candy observed that
plasma arginine is positively associated with
both systolic and diastolic blood pressure
and that arginine, and amino acids gener-
ally, may be a valuable tool in identifying
non-traditional risk factors for hyperten-
sion. Further studies are needed, however.
Treating of
Helicobacter pylori
lowers blood pressure in black
South Africans with hypertension
Dr Geoff Candy, University of the Witwa-
tersrand, Johannesburg
Helicobacter pylori is a gram-negative bac-
terium that colonises the human stomach,
causing chronic inflammation. Its preva-
lence in the African population is in the
region of 90% and these people are also
especially susceptible to the hypertension
and stroke, kidney disease and heart fail-
ure that it can cause. It has been suggested
that H pylori plays a causal role in these
patients’ hypertension.
Reviewing a study of which he was lead
author, Dr Candy evaluated what hap-
pened to the blood pressure of a study
group whose H pylori was eradicated by a
course of antibiotics. Successful eradication
of H pylori with optimal quadruple therapy
was associated with a mean awake blood
pressure decrease of –5.4 mmHg (systolic)
and –3.4 mmHg (diastolic).
This confirmed the results of another
study. ‘While the study confirmed that
eliminating H pylori had a beneficial effect
on blood pressure, the mechanisms/rela-
tionship remain unclear and require eluci-
dation by further studies’, he concluded.
Cardiovascular function and psycho-
logical distress in urbanised black
South Africans: the SABPA study
Dr Nyiko Mashele, Potchefstroom
University
Does psychological distress contribute to
the increasing prevalence of cardiovas-
cular risk factors in sub-Saharan Africa?
The answer is still unclear, but the envi-
ronmental demands of urbanisation and
loss of social and cultural support may
diminish people’s ability to adapt and
cope, with behavioural, psychological and
social consequences. Nyiko Mashele, of
the Hypertension in Africa research team
at Potchefstroom University, gave an over-
view of the findings of the SABPA study,
which examined this issue further. She is
also lead author of the paper presented at
the congress.
‘The association between depression
and hypertension compares favourably
with established risk factors such as obes-
ity’, she said. ‘The aim of our study was to
investigate the relationship between car-
diovascular function and psychological dis-
tress in 200 urbanised black South Africans
of similar socio-economic status.’ Patients
were stratified into hypertensive and nor-
motensive groups according to ESH 2007
guidelines.
The study found that depression was
indeed significantly associated with certain
measured cardiovascular variables. Psycho-
logically distressed hypertensive African
men tended to have higher blood pres-
sures than those who were not depressed.
Depression was also associated with the
development of left ventricular hypertrophy
in both hypertensive men and women.
Ambulatory versus conventional
blood pressure control in an urban
developing community of African
ancestry
Dr Muzi Maseko, Cardiovascular Patho-
physiology and Genomics Research Unit,
School of Physiology, University of the Wit-
watersrand, Johannesburg
‘We know that blood pressure is associated
with heart failure in developing communi-
ties and that hypertension is the cause of
more than 30% of cases seen in Soweto.
It is therefore a serious problem and we
need to pay special attention to treating
to target.’ This is according to Dr Muzi
Maseko, lead author of a study that evalu-
ated ambulatory blood pressure monitor-
ing (ABPM) relative to office measurement
– five high-quality clinic readings.
The study found that regardless of the
device used, ABPM was superior when it
came to predicting target-organ damage
and was also a far more accurate indica-
tor of a patient’s blood pressure status.
Maseko and his team found that con-
ventional blood pressure measurement
considerably overestimated the extent of
inadequate blood pressure control, which
could result in a considerable cost burden
to South Africa. ‘As a result of these mis-
leading office measurements, patients are
being treated unnecessarily. ABPM would
show that they do not need treatment’, he
concluded.
Does ambulatory arterial
stiffness approximate arterial
stiffness effects when estimating
associations with target-organ
changes?
Dr Olebogeng Majane, Cardiovascular
Pathophysiology and Genomics Research
Unit, School of Physiology, University of the
Witwatersrand, Johannesburg
Dr Olebogeng Majane presented the results
of a study he and his team had undertaken
to address this question. They evaluated
459 randomly selected patients to deter-
mine whether the relationship between the
ambulatory arterial stiffness index (AASI)
and target-organ changes correlated with
that between carotid–femoral pulse-wave
velocity (PWV) and target-organ changes.
Although a correlation had been found
in other studies, Majane and his team
found that the relationship between PWV
and target-organ damage remained,
regardless of the AASI. They therefore con-
cluded that AASI is a poor approximate of
the relationship between PWV and target-
organ damage. ‘It should not be used as a
surrogate’, Dr Majane concluded.
Report compiled by P Wagenaar and
J Aalbers, Special Assignments Editor
