Non-invasive nerve stimulation shows potential for treating uncontrolled high blood pressure

The findings from the SCRATCH-HTN trial, published in the American Heart Association journal Hypertension, suggest the technique could warrant further investigation as a potential treatment for some patients whose blood pressure remains high despite medication.

The study investigated transcutaneous autonomic neuromodulation (tAN), a non-invasive technique designed to influence the autonomic nervous system, which plays an important role in regulating blood pressure.

The small handheld device, developed by Afferent Medical Solutions, delivers gentle electrical stimulation through two clips attached to the tragus – the small piece of cartilage at the front of the ear. Patients can administer the treatment themselves at home.

The NIHR-funded trial involved 63 patients with uncontrolled hypertension who were already taking one or more blood pressure medications. Participants were randomly assigned to receive either active treatment or a sham device. They used the device for 30 minutes each day for two weeks and then once a week for a further 10 weeks.

The treatment was found to be safe and well tolerated, with high levels of adherence among participants.

The trial did not find a significant difference in blood pressure reduction between the active treatment and sham groups across the overall study population.

However, a prespecified subgroup analysis found a greater reduction in blood pressure among participants who had more severe hypertension at the beginning of the trial. The researchers say this finding should now be investigated in larger studies designed to establish which groups of patients, if any, are most likely to benefit.

Dr Ajay Gupta, Chief Investigator, Clinical Reader at Queen Mary University of London and Consultant Physician at Barts Health NHS Trust, said:

“This is an exciting, highly patient-acceptable technology that could ultimately provide a cheap, scalable solution for millions. Although the trial did not achieve significance across the broad unselected group, those with more severe hypertension exhibited a clear blood pressure reduction in the active group compared to sham.

“As the first and most thorough study of its kind, this points towards important new research directions that could help us understand whether non-invasive neuromodulation can benefit particular groups of patients with uncontrolled hypertension.”

High blood pressure is a major risk factor for cardiovascular disease, including heart attack and stroke. A substantial proportion of people being treated for hypertension continue to have blood pressure above recommended targets despite taking medication.

The researchers say larger trials are now needed to investigate the findings and determine whether a more targeted approach could identify patients most likely to benefit from the treatment.

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