18 LISTENER SEPTEMBER 14 2019
doses. Doctors say serious weight loss
can cause meaningful reductions in
blood pressure. “For every kilo you lose,
your systolic (top) reading might come
down by 1-2mm of mercury,” says
Auckland City Hospital cardiologist
Matt Dawes, who is liaising with
medical-school
researchers on
the hypertension
studies. “If you
can lose 10kg, the
systolic reading
can come down
by approximately
15mm of mercury,
which is what
you’d expect a
drug to do. In an
appropriate person,
it is very good
blood-pressure
control.”
A significant pro-
portion of treated
hypertensives don’t
get below the rec-
ommended 140/90,
he says, despite being on two, three or
even four different medications. “Once
you start getting on that number of
meds, you increase the chances of side
effects. The patient thinks the tablets
are only making them feel worse, and
they’re clearly not making them feel
better, because
they didn’t feel bad
in the first place.
There needs to be a
good doctor-patient
relationship over
time to maintain
good adherence.”
Singh says
he’s never felt
better. “Before, if
I did any physical work for 20 or 30
minutes, it would exhaust me. Now,
it’s like the difference between a day
with thunderstorms and a sunny
spring day.”W
est Auckland petrol-station
owner Vikram Singh, 52,
had many reasons to get fit
and lose weight in 2017. He
wanted to be in good shape
for his 20th wedding anniversary and his
blood pressure – already being treated with
four different drugs
each day – was
starting to creep
up again. “There
comes a time in life
when you have to
do something to be
better than what
you are. It was a big
worry, for sure.”
He was first
diagnosed with
hypertension in
his late thirties,
and his untreated
reading was
170/100. He says it
didn’t help when
his weight started
to rise as well,
reaching a peak of
93kg a couple of years ago. To maintain
his blood pressure at 125/80, he was
on the angiotensin converting enzyme
(ACE) inhibitor cilazapril, the calcium
channel blocker amlodipine, the beta
blocker bisoprolol and an alpha blocker,
doxazosin.He originally planned to
lose just a few
kilograms ahead
of his wedding
anniversary, but
his new regime –
walking, working
out on a stationary
bike for about 30
minutes at a time,
minimising his
sitting time and
giving up sugar and carbs – has stuck, and
he has now lost almost 20kg. His blood
pressure has fallen to 110/70 and is being
maintained on just three of the four drugs
(amlodipine has been stopped), at reducedExercise and diet changes can help reduce
the need for blood-pressure drugs.
centre of excellence for heart research, but a
decision on that won’t be made until 2021.
One of the Auckland investigators is Fiona
McBryde, who worked with Paton in Bristol
on the carotid body studies. She returned
to New Zealand in 2013, after winning the
$500,000 Sir Charles Hercus Research Fel-
lowship, to study the role of the “selfish
brain” in regulating blood pressure.
McBryde says researchers have known for
many years that the walls of blood vessels
that supply the brains of people who havehypertension show signs of thickening, but
this was always assumed to be a protective
response to high blood pressure. In fact, she
says, impaired brain blood flow can occur
early and may be a primary trigger for high
blood pressure. In 2015, she was awarded a
$1 million, three-year HRC project grant to
investigate how and why the brain responds
to the reduced blood flow and low brain
oxygen that occur during a stroke. Her
laboratory can both see and measure blood
flow to the brain thanks to a $1 million piece
of equipment donated by the AH Somerville
Foundation. “We can look in real time in
the brain as the stroke is happening and we
can look at the effect of blood pressure on
stroke size, which we think is critical to try
to salvage as much brain tissue as we can.”
Although about half of stroke patients
have a history of hypertension, some will
have normal pressure, and others will be
on treatment. But 85% of patients will
have a big surge in blood pressure after
their stroke – an increase of 30-40mm
of mercury. “If you have a blood vessel
completely occluded, you’ve got part of the
brain downstream from that with very little
or no blood flow, so ‘turning up the hose’
can make it easier for blood to get in there
and rescue that stroke area – that’s what the
body is trying to do.”
So, what are the ramifications for aggres-
sive blood-pressure control in those first
hours or days after a stroke, if the brain is
A actually protecting itself? And what should
N
GIEHU
MPHR
EYSHYPERTENSION
‘I lost almost 20kg’
“If you can lose 10kg, the
systolic reading can come
down by approximately15mm of mercury,
which is what you’dexpect a drug to do.”
Vikram Singh: Never felt better.Paton believes a novel
drug, known as a
purinergic receptorantagonist, will dial down
the carotid bodies and
sympathetic activity andlower blood pressure.