SCRATCH HTN
Research type
Research Study
Full title
Sham controlled Randomized Control Trial evaluating the Safety, Acceptability and Efficacy of Autonomic neuromodulation using trans-cutaneous vagal sensory stimulation in uncontrolled hypertensive patients: a pilot study evaluating a novel non-invasive device-based strategy.
IRAS ID
302061
Contact name
Ajay Gupta
Contact email
Sponsor organisation
Barts Health NHS Trust & Queen Mary University of London
ISRCTN Number
ISRCTN14509154
Clinicaltrials.gov Identifier
Duration of Study in the UK
1 years, 2 months, 29 days
Research summary
Summary of Research
High blood pressure (BP) is the leading risk factor for death and illness from a cardiovascular event, and managing high BP is a key focus of treatment for cardiovascular diseases. Antihypertensive drugs (drugs that aim to lower BP) are widely available, however a high number of people with high BP fail to achieve a healthy BP value despite receiving 1 or more anti-hypertensive medications. For uncontrolled hypertensive patients, including drug-resistant patients, the lack of an effective therapy is a major health challenge and an urgent unmet clinical need.
One potentially highly effective strategy to improve BP control in hypertension is via redressing the nervous system imbalance, which is linked with the development of hypertension; the brain controls the cardiovascular system by sending commands through the nervous system.
In this study, we will utilise a device that produces a very small electrical current to the nerves at the front area of the ears (the tragus). With this strategy, we aim to redress the nervous system imbalance and treat hypertension.
We aim to enrol 63 hypertensive participants, who will be randomly be allocated to receive the active or the inactive device in a 2:1 ratio (neither the clinical study team nor the participants will know who will receive the active device and who will receive the inactive). The participants will be asked to use the device for 30 minutes, daily for the first 14 days of the study, and then, once weekly for 10 weeks. The aim of the study is to establish that the device is safe, easy to use and acceptable by the patient, and that it has the potential to lower blood pressure in hypertensive patients.Summary of Results
Study Aim – Why the study was carried out.Many hypertensive patients fail to achieve the recommended blood pressure targets, because either the medication doesn't work, or the patient gets side effects from the medication. Alternative treatments for this ‘uncontrolled’ blood pressure (BP) are expensive and invasive.
The main aim of the SCRATCH-HTN early phase study was to test whether a new non-invasive device treatment could be safe and acceptable to patients, and whether it may help lower BP in patients with uncontrolled high BP.
This was done using the AffeX-CT device, which provided a very small electrical current to the ears. This treatment method is known as transcutaneous autonomic neuromodulation (tAN), and it can stimulate the nerves that control BP. We also wanted to see if the study subjects thought the device was safe, easy to use and acceptable.
Study Methods – What the researchers did.
Eligible participants self-administered the device treatment (active tAN or sham-tAN) using clips attached to a specific part of the ear (the tragus) for 30 minutes a day for 14 days, then once a week for 10 further weeks. This means that the treatment period was 3 months in total. During these 3 months, other tests were done to capture data for the trial, such Office BP and 24-hour ambulatory blood pressure monitoring (ABPM) to measure BP and heart rate, electrocardiogram (ECG), echocardiogram (ECHO), and questionnaires for quality of life and sleep quality.
Study Results – What the researchers found.
Of 170 subjects screened to take part in the study, 63 subjects were randomly assigned in a 2:1 ratio to either an active device or a sham (inactive) device which looks like an active device but does not provide any real treatment. This means 41 subjects were given an active device, and 22 subjects were given a sham (inactive) device. Only two subjects (who were in the sham device group) did not complete their treatment, so the final data analysis included 61 subjects.
The average age of these subjects was 47.7 years, and 44 (72.1%) of the 61 patients were male. The average daytime BP at baseline, as measured by 24-hour ABPM, was 150/95 mmHg. Most subjects were already treated on average with 2 blood pressure-controlling drugs (range between 1 and 4 medications).
At the end of the study, subjects from both active and sham groups showed improvements in BP as compared to their baseline BP. However, there was no statistical difference in BP at the end of the study (after 3 months treatment) between the two groups. There were also no significant differences between the two groups in the change in other measures, such as heart rate, quality of life or sleep quality.It was observed that subjects with higher systolic BP (greater than 160 mmHg) at the start of treatment showed a significantly greater reduction in systolic BP following active device treatment, as compared to those randomly allocated to the sham arm.
The trial subjects in both groups said that the device was easy to use and compliance with the device treatment regimen (number of days the device was used) was very good. Regarding device safety, there were no serious adverse events reported indicating that the device is safe and well-tolerated in those with uncontrolled high BP.
One of the limitations of the study was that at least half of the subjects correctly guessed which allocation (Sham or Active) they were on at the end of the treatment (3 months), and that may have (in addition to the low number of study subjects) affected the results.
Conclusion – What the results means for patients with high blood pressure.
The study data show no safety concerns and good acceptability of the tAN device, suggesting that the device can be used in patients if proved to be effective at reducing BP. However, both groups recruited in this trial showed similar BP reductions. This means that based on the SCRATCH trial results, there will be no immediate change in the current treatment methods for patients with uncontrolled BP.
However, there are some suggestions from the data that the device treatment may show increased benefit in patients with more severe hypertension (systolic BP greater than 160mmHg). This data warrants further testing in future studies.
REC name
West of Scotland REC 4
REC reference
21/WS/0157
Date of REC Opinion
10 Jan 2022
REC opinion
Further Information Favourable Opinion