Blast of sound waves to cut high blood pressure

STIMULATING the forearm with a handheld ultrasound device may be a new way to treat high blood pressure, or hypertension. a recent study involving 250 people showed that using the device for just 20 minutes significantly reduced patients’ blood pressure. The theory is that the ultrasound waves interfere with signalling from a nerve in the forearm that also travels to the heart and is involved in regulating blood pressure. The Japanese research-ers say the ultrasound treatment may be so effective that some patients won’t need to take hypertension medication. most people with hypertension — defined as a blood pressure reading of 140/ 90mmHg — need pills such as ACE inhibitors or calcium channel blockers to control their condition, but it’s estimated that in more than half of patients their high blood pressure remains hard to control. in recent years, scientists have been investigating new ways to tackle the problem. For example, using radiowaves to destroy the renal nerves in the kidney — these help to regulate blood pressure by transmitting information between the kidneys and the brain. another advance has been in ultrasound ( sound waves above the range of human hearing). its use has been researched widely in medicine, for example in scans and as a treatment for lower back pain, depression and in boost-ing bone healing after fractures. Ultrasound has the advantage of being cheap and non- invasive. now it has been applied to blood pressure after researchers noticed that using ultrasound devices on the forearm for other applications also appeared to have an effect on people’s blood pressure. The treatment involves having a handheld ultrasound device — much like the device used for ultrasound scans — placed against the forearm for 20 minutes ( the treatment is painless). a recent study of more than 200 patients with hypertension at Tohoku University graduate School of Biomedical engineering, Japan, found that a single session reduced systolic blood pressure (the upper number — the pressure after the heart contracts) by ten to 23 points on average compared with patients given a placebo.

The researchers suggest that if used with medication, ultrasound may boost the blood pressure-lowering effects, and that ‘some patients may be able to reduce hypertensive medication or may not need to take it at all’. Just how the ultrasound therapy works in reducing blood pressure is unclear.

But the researchers — who also measured the amount of blood being pumped out by the heart and the pulse rate — found that these, too, were significantly lower after ultrasound treatment, reports the international Journal of Cardiology.

This suggests there is a direct effect on the blood pressure mechanism. The theory is that the ultrasound signals interfere with sympathetic nerves which have branches in the forearm and lead to the heart.

overactivity of the sympathetic nervous system has been linked to high blood pressure.

COMMENTING on the research, Dr richard Perry, clinical lead for hyperacute stroke research at Univer-sity College london Hospitals NHS Foundation Trust, said: ‘The studies from Tohoku University make a very interesting observa-tion — that blood pressure can be lowered quite substantially within about 20 minutes using ultrasound to the forearm.

‘Whether the blood pressure could be kept lower for months or years using this technique, as would be needed to have any impact on preventing stroke and heart disease, is entirely unknown.’

However, he says the technique may have a place in a& e in patients who have had strokes where it is common to try to reduce blood pressure quickly, either to allow clot-busting medications to be given or to reduce life-threatening bleeding in the brain.

‘rapid blood pressure reduction using this technique could be a very fruitful direction for future research,’ he told good Health.