Predicting the risk of a cardiovascular event generally involves doctors looking at factors such as someone’s cholesterol levels and blood pressure, as well as medical history, age and weight.
Even when all of that is assessed, many people are missed. The risk prediction tool doesn’t put them at the threshold where they are identified as needing preventive treatment and the first symptom of vascular disease may be a heart attack or stroke.
GP William Ferguson believes we need to do better. In his West Auckland practice, he has conducted an informal trial of a piece of equipment he is convinced can make a difference.
A pulse wave analysis (PWA) machine is similar to a traditional blood pressure monitor (an inflatable cuff on the arm) but gives additional information. It analyses the shape of the pulse wave coming from the heart – the greater the reflected wave, the stiffer the blood vessels are and the higher the risk of a problem.
It also monitors central blood pressure, which has been shown to be a better predictor of vascular disease than peripheral blood pressure.
Ferguson tested a PWA machine on three groups of patients. One group was very healthy and considered low-risk, one was known to have arterial disease, and the third was somewhere in the middle.
“We didn’t really know how seriously we should take their cardiovascular risk, which, of course, is the central problem,” says Ferguson.
The test showed that many of the people in that intermediate zone had signs of vascular disease and were unknowingly on track to a heart attack or stroke.
“It made us sit up and take notice, leading us to be much more aggressive with preventive treatment or further investigation,” says Ferguson. “In some cases, we sent patients to a cardiologist or for a calcium score test [a CT scan that gives more information about how blocked the coronary arteries might be]. With others, we fine-tuned medication or got serious with lifestyle interventions.”
Ferguson said what was interesting was getting those patients to return for another PWA test six to eight weeks later and seeing the results of their interventions. “It made me realise the tool is really motivating for patients because they can see what is going on with their arterial health.
“We had sedentary people who started exercising and it had effects on their arterial elasticity very quickly. Another person, whose diet hadn’t been good, changed it quite drastically and again the numbers were transformed.”
Ferguson now has a nurse at his practice who is trained to use the PWA machine. “It’s a non-invasive and easy-to-use tool,” he says. “When a patient walks through the door there’s no way of knowing how at risk they are.
“This can help us zero in on those who need the preventive treatment, and not bother the ones who might have a bit of raised cholesterol but have nothing wrong with them.”
A PWA session takes about 30 minutes and costs $79-$100. A handful of pharmacies around the country are participating in the service at present (go to healthscreeningnz.com for locations) though that is expected to be expanded and doctors’ surgeries, gyms and corporates will also offer a screening programme called CardiAction.
Carolyn Oakley-Brown, managing director of Health Screening NZ, was motivated by her father’s sudden and unexpected death from a heart attack. She says the test can give peace of mind as well as alert people who need to improve their heart health. Screeners are trained to identify who should be referred to a GP and which clients will be able to turn things around by improving diet, becoming more active and taking supplements to reduce inflammation.
“It’s about working with the individual on areas where they’re able to make change,” says Oakley-Brown.
She advises annual screening for those in the “healthy maintenance” phase and for people at more elevated risk to repeat every 3-6 months to check that lifestyle changes are having the desired effect.
“About 50% of the people we screen have unidentified heart disease, which is staggering,” she says.
