Wrist-worn device to revolutionise blood pressure measurement
22 Feb 2011
A new method of measuring blood pressure by recording the
pulse wave in the wrist gives a more accurate reading than the
traditional arm cuff.
The new approach, invented by scientists at the University of
Leicester and Singapore medical device company HealthSTATS
International, accurately measures the pressure close to the heart —
the central aortic systolic pressure or CASP. It has the potential
to enable doctors to treat their patients more effectively.
Blood pressure is currently measured in the arm because it is
convenient. However, this may not always accurately reflect what the
pressure is in the larger arteries close to the heart.
In the new system, a sensor on the wrist is used to record the
pulse wave and then, using computerised mathematical modelling of
the pulse wave, accurately calculate the pressure close to the
heart. Using this approach, central aortic systolic pressure can be
measured non-invasively with an accuracy of 99%. It has been
verified by comparing the pressure measured by inserting a catheter
directly into the aorta close to the heart during a cardiac catheter
procedure.
Patients who have tested the new device found it easier and more
comfortable, as it can be worn like a watch.
Being able to measure blood pressure in the aorta which is closer
to the heart and brain is important because this is where high blood
pressure can cause damage. In addition, the pressure in the aorta
can be quite different from that traditionally measured in the arm.
The new technology will hopefully lead to better identification
of those who will most likely benefit from treatment by identifying
those who have a high central aortic systolic pressure value. This
will be especially important for younger people in whom the pressure
measured in the arm can sometimes be quite exaggerated compared to
the pressure in the aorta.
A key question is whether measurement of central aortic pressure
will become routine in clinical practice. Professor Williams said:
“It is not going to replace what we do overnight but it is a big
advance. Further work will define whether such measurements are
preferred for everybody or whether there is a more defined role in
selective cases to better decide who needs treatment and who doesn’t
and whether the treatment is working optimally.”
The University’s close collaboration with the Singapore-based
medical device company HealthSTATS International has led to the
development of this world-first technique for more accurate blood
pressure measurement.
HealthSTATS has developed a range of blood pressure measurement
devices that are enabled to measure central aortic systolic pressure
(CASP), namely A-PULSE CASP, CASPro and CASPal, which are designed
for hospital, clinical and home use respectively. All three medical
devices have attained the FDA 510(k) listing and CE (MDD) Mark. For
the purpose of this research, the A-PULSE CASP was used.


The CASPro (left) and CASPal (right) devices
from HealthSTATS
The research work carried out by the University of Leicester was
funded by the Department of Health's National Institute for Health
Research (NIHR). The NIHR has invested £3.4million with a further
£2.2million capital funding from the Department of Health to
establish a Biomedical Research Unit at Glenfield Hospital,
Leicester, dedicated to translational research in cardiovascular
research.
The work, led by Professor Bryan Williams, Professor of Medicine
at the University of Leicester and consultant physician at
University Hospitals of Leicester NHS Trust.
Professor Williams, who is based in the University of Leicester’s
Department of Cardiovascular Sciences at Glenfield Hospital, said:
“I am under no illusion about the magnitude of the change this
technique will bring about. It has been a fabulous scientific
adventure to get to this point and it will change the way blood
pressure has been monitored for more than a century. The beauty of
all of this, is that it is difficult to argue against the
proposition that the pressure near to your heart and brain is likely
to be more relevant to your risk of stroke and heart disease than
the pressure in your arm.
“Critical to the success of this project has been the synergies
of combining clinical academic work here with HealthSTATS and their
outstanding medical technology platform in Singapore. This has been
the game-changer and I really do think this is going to change
clinical practice.”
Dr. Choon Meng Ting the Chairman and CEO of HealthSTATS said:
“This study has resulted in a very significant translational impact
worldwide as it will empower doctors and their patients to monitor
their central aortic systolic pressure easily, even in their homes
and modify the course of treatment for BP-related ailments.
Pharmaceutical companies can also use CASP devices for clinical
trials and drug therapy. All these will ultimately bring about more
cost savings for patients, reduce the incidences of stroke and heart
attacks, and save more lives.”
Professor Dame Sally Davies, Director General of Research and
Development and Interim Chief Medical Officer at the Department of
Health, said: “This is fantastic work by Professor Williams and his
team and I am delighted to welcome these findings. I am particularly
pleased that the clinical research took place at the NIHR Biomedical
Research Unit in Leicester. NIHR funding for Biomedical Research
Centres and Units across England supports precisely this type of
translational research, aimed at pulling-through exciting scientific
discoveries into benefits for patients and the NHS by contributing
to improved diagnostics and treatments.”