Almost everyone has had their blood pressure measured with an inflatable cuff around the arm. But as useful as this is, it can differ from the reading at the heart itself.
Twenty years ago Sydney scientists found a way to get that extra information. They created a model that gives the pressure at the main artery of the heart, using the wrist’s pressure pulse (the shape of the ‘waves’ that both travel along arteries when the heart pumps blood, and travel back to the heart as it fills with blood).
The model wasn’t applicable to children, since their limbs are still growing – so now they’re adapting it to fit.
“We have guidelines on when to treat people for abnormally high blood pressure, or hypertension,” says Professor Alberto Avolio of Macquarie University, who developed the model with Professor Michael O’Rourke of St Vincent’s Hospital.
“But people who are ‘normal’ at their arm may have quite different systolic pressures at their heart, or vice versa.”
In the 1950s English physiologist Donald McDonald and mathematician John Womersley recognised this problem and began investigating how blood flow changes as it moves through arteries.
The model that came from their ideas has transformed the measurement of blood pressure around the world, and spawned Australian company AtCor Medical along with many others overseas. But it’s never worked for children, and that’s what they’re now attempting to fix.
“Diseases of the heart and blood vessels still kill more people than all cancers combined,” Alberto says.
“One of the most important and modifiable aspects of these diseases is hypertension.”
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