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VOLUME 13 NUMBER 2 • DECEMBER 2016
99
SA JOURNAL OF DIABETES & VASCULAR DISEASE
DIABETES NEWS
A
fricaPCR 2016, the third edition of
the continent’s premier interventional
cardiology meeting, got under way
in Johannesburg on 10 March with a
plenary session devoted to the topic of
hypertension in Africa and, specifically,
whether interventional measures, notably
renal denervation, have a role to play in its
treatment, either as complementary or as
an alternative to drug therapy, particularly
given the compliance issues often associated
with the latter.
Hypertension was a major focus of the
meeting further to a needs analysis, which
identified the magnitude of the problem
in Africa. Prof Mpiko Ntsekhe from the
University of Cape Town cited a 1929
study involving 2 000 Kenyan subjects in
whom there was a complete absence of
hypertension.Nearlyacenturylater,however,
the picture has changed dramatically. The
bulk of the world’s hypertension burden is
now in Africa, with an estimated prevalence
of more than 60% in adults over 60 years.
There are many reasons for this, including
urbanisation, poverty and social deprivation,
dietary changes entailing high salt and
saturated fat intakes, alcohol abuse and
rising obesity. ‘Hypertension is the biggest
contributor to the risk of myocardial infarction,
stroke and heart failure, as well as chronic
kidney disease and cardiovascular mortality.
It is therefore a major contributor to overall
morbidity and mortality across the continent.’
When it comes to addressing the problem
– awareness, treatment and control – the
figures are ‘really dismal’. ‘Treatment rates
are under 20% and only a little over 5% of
patients are controlled, and that’s using the
old targets. As healthcare professionals we
need to change this.”
What should the targets be?
Prof Bernard Gersh from the Mayo Clinic,
USA, underscored the seriousness of
hypertension as a worldwide problem.
‘Some one billion people are hypertensive
and it’s the major reason for office visits.
The hurdles to combating it are universal.’
Several trials have shown the benefit
of systolic blood pressure control in
older patients, although the results were
not always consistent. The 2014 JNC-8
Hypertension in Africa: what role can interventional strategies play?
guidelines, based on the evidence from
randomised, controlled trials, recommend
relaxed targets of 150 mmHg in those
over 60 years with no other health issues
and 140 mmHg in those with diabetes and
chronic renal failure. ‘These targets were
already the subject of contention, but then
the game changed with the SPRINT trial’,
said Prof Gersh.
The study involved an intensively treated
arm with a systolic blood pressure target
of < 120 mmHg, and another that received
standard treatment with a target of
< 140 mmHg. Key to the trial was that the
intensively treated arm received three drugs
per patient as opposed to an average of
1.9 in the standard arm. The study was
stopped early owing to the significantly
lower rate of the primary composite
outcome myocardial infarction, acute
coronary syndrome, stroke, chronic heart
failure, cardiovascular death and all-cause
death – in the intensively treated group.
Prof Gersh believes that the major
benefit seen in SPRINT redefines systolic
blood pressure targets, ‘150 mmHg is
simply too high. The questions are whether
we should extrapolate the SPRINT results
to younger patients and diabetics and I
think it’s something we should consider.
However, determining optimal thresholds in
these groups will require more randomised
trials. In the interim, based on the results of
SPRINT, for most patients, lower is better.
Intuitively, this makes sense. So why not
aim for < 120 mmHg if it is relatively easily
achievable and tolerable for the patient?’
Is renal denervation a viable
option for treating hypertension?
Prof Gersh underscored that sympathetic
nervous activation plays a crucial role
in cardiovascular disorders. ‘Multiple
unblinded trials have shown that renal
denervation lowers blood pressure by
20–30%. The epidemiological implications
of this are enormous. For some patients, a
renal denervation procedure every five years
might actually be preferable to lifelong
multidrug therapy.’ That said, he feels
current levels of denervation are probably
suboptimal.
Contradicting the findings of earlier
unblinded trials, however, SYMPLICITY
HTN-3, a prospective, single-blind,
randomised, sham-controlled study, did
not show a significant reduction in systolic
blood pressure in patients with resistant
hypertension six months after renal artery
denervation, compared with the sham
control group. ‘All good trials raise new
questions and both SYMPLICITY HTN-3
and SPRINT have done just that’, said Prof
Gersh.
Newer trials currently under way
are assessing the effectiveness of renal
denervation alone and in conjunction with
drugs. ‘In two years, we’ll have the definitive
answers to the following questions. Does it
work? How does it compare with drugs?’
In the discussions that followed, it was
concluded that there is currently a lack of
strong scientific evidence to support the
wide use of renal denervation, but that if
that evidence becomes clear, it will have
major implications, given widespread non-
compliance with medication. However,
even when the evidence becomes available,
careful patient selection will still be
imperative.
Source:
AfricaPCR 2016
Diabetes News