Ultrasound to cut blood pressure if the drugs don’t work

BlastiNg the neck with ultrasound waves could help patients with high blood pressure when pills don’t work. the treatment involves using ultrasound to destroy one of the smallest organs in the body, the carotid bodies. there are two of these rice-grain sized bodies in the neck, near the arteries that supply the brain. they play a key role in the control of blood pressure.

Untreated, high blood pressure increases the risk of heart attacks, stroke and kidney damage.

the ideal blood pressure is considered to be between 90/60mmHg and 120/80mmHg (the top number, the systolic blood pressure, is the pressure after the heart contracts; the lower, the diastolic, is blood pressure when the heart is at rest).

a 20mmHg rise in both readings doubles the risk of death from cardiovascular disease, and each 2 mmHg rise increases the risk of stroke by 10 per cent, according to a study by the University of auckland and other centres. the same study, published in the journal autonomic Neuroscience, reports that only around half of treated patients have adequate blood pressure control.

THere have been no new drug treatments for hypertension for two decades, and researchers have been focusing on non-drug treatments. More than 10,000 patients worldwide have undergone one such treatment, renal denervation, where the nerves around the arteries that supply the kidneys — thought to control blood pressure — are destroyed. However, some research shows only half of patients will benefit.

the new ultrasound treatment involves destroying one of the two carotid bodies. these small bodies of tissue are rich in capillaries (tiny blood vessels) and contain cells that detect levels of oxygen and carbon dioxide in the blood, and monitor blood flow in the brain. if they detect these are too low, they send messages to the brain to increase breathing and blood pressure.

one theory is that in some people with high blood pressure, the carotids are hypersensitive and overreact, triggering constant high blood pressure. studies in animals and humans have shown that surgically removing one of the carotid bodies leads to an immediate and sustained fall in blood pressure, greater than can be achieved with medications in some cases.

in a 2016 study at Bristol University, 15 patients underwent the surgery and more than half experienced a reduction in blood pressure of 26 mmHg.

the ultrasound version of the treatment, developed by cibiem in the U.s., is less invasive than surgery and takes 60 to 90 minutes. Unlike standard ultrasound, which is administered outside the body, a catheter or tube is inserted into a major vein in the thigh through a small surgical incision, and then fed into the jugular vein in the neck to target the carotid body.

trials are under way at the royal Perth Hospital in australia, the Medical University of gdansk, in Poland, and Na Homolce Hospital, in the czech republic, with around 30 patients.

commenting on the technique, Dr Mel lobo, director of the Barts Blood Pressure centre of excellence, says: ‘We await the results of further studies with great interest and, in particular, it will be important to determine if destruction of one or both carotid bodies will be necessary to achieve long-term reduction in blood pressure.

‘it will also be important to determine why the carotid bodies become hyperactive in some patients and whether this is preventable.’

MeaNWHile, low levels of both vitamin D and K may raise the risk of developing hypertension, according to a study in the journal Hypertension.

Dutch researchers analysed health records of around 600 people with and without hypertension and found the risk of high blood pressure was increased by more than 62 per cent in people with a deficiency in both vitamins.

the exact mechanisms are unclear, but both vitamins are linked to cardiovascular health. Vitamin K is found in green leafy veg and vitamin D is in fatty fish.