SCRATCH-HTN Study: Evaluating Autonomic Neuromodulation Using Trans-cutaneous Vagal Stimulation in Hypertensive Patients (SCRATCH-HTN)

November 17, 2025 updated by: Queen Mary University of London

Sham Controlled RCT Evaluating the Safety, Acceptability and Efficacy of Autonomic Neuromodulation Using Trans-cutaneous Vagal Stimulation in Uncontrolled Hypertensive Patients: a Pilot Study

This is a pilot, sham-controlled, double blind, single-site device clinical trial designed to evaluate the safety, acceptability and efficacy of non-invasive autonomic neuromodulation in a cohort of 63 adult patients with uncontrolled high blood pressure.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

SCRATCH-HTN trial is a randomised sham-controlled study designed to evaluate the safety, acceptability, and efficacy of trans-cutaneous autonomic neurostimulation (tAN) in a cohort of uncontrolled medicated hypertensive patients.

SCRATCH-HTN trial is designed to test the hypothesis that tAN treatment is safe and acceptable to the patient, improves the control of blood pressure in hypertension and sense of well-being amongst those who are receiving the active treatment as compared to those on sham treatment.

The study will recruit 63 patients with systemic arterial hypertension (male and female aged ≥18 years) who are receiving between one and three oral antihypertensive medications and remain hypertensive with blood pressure (BP) above target levels detailed below in the eligibility criteria. The participants will be randomly allocated to the active (tAN) or sham (sham-tAN) arms of the trial on 2:1 basis, respectively.

The total treatment duration is 12 weeks. Self-administration of 30 min of tAN or sham stimulations once per day for the first two weeks, and then once every week for the rest of the trial period.

Study Type

Interventional

Enrollment (Actual)

63

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United Kingdom
      • London, United Kingdom, E1 1FR
        • Barts Health NHS Trust

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 79 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Participant has given written informed consent.
  2. Participant has sufficient knowledge of the English language to be able understand the participant information sheet and trial materials including outcome assessments.
  3. Participant is aged ≥18 years and <80 years at the time of screening visit.
  4. Participant is taking between 1 to 4 antihypertensive medications (inclusive) at time of screening and baseline (randomisation) visit and is willing to adhere to no change in medication during the trial until end of the trial visit (visit 5). (NB. Participant on only one antihypertensive medication should be taking that medication for at least six weeks prior to the screening visit).
  5. Participant has confirmed diagnosis of hypertension.

  6. Participant meets BP criteria:

    • 24-hour ambulatory BP monitoring (ABPM) at either screening visit or baseline (randomisation) visit, with mean daytime SBP of ≥135 mmHg and <170 mmHg and mean daytime DBP of ≥85 mm Hg and <115 mmHg (N.B. By default, Ambulatory Blood Pressure Monitoring [ABPM] at screening visit will be used at baseline visit. However, if there has been an addition of new medication after participants screening visit, 24-hour ABPM must be repeated at baseline visit).

  7. Participant has one or more of the following associated conditions:

    1. Obesity: BMI >30 or waist circumference >94 cm (men) or > 80cm (women). (NB. For participants of South-East Asian/Chinese/Japanese origin these cut-offs are >90 cm (men) or >80 cm (women)).
    2. Type 2 diabetes - controlled or sub-optimally controlled (HbA1c ≤8.5% or ≤69 mmol/mol) on diet and/ or medications except insulin.
    3. Heart rate (average) ≥70 bpm at screening or baseline (randomisation) visit (measurement taken after 5 minutes of rest in a seated position and when finger probe has been placed for a minimum of 30 seconds thereafter) or a heart rate (average) ≥60 bpm at screening or baseline (randomisation) visit if the patient is taking beta-blocker medication.
    4. HbA1c ≥42 mmol/mol or fasting blood glucose (if available) ≥5.6 mmo/L AND either low HDL cholesterol (≤1.03 mmol/L for men and ≤1.29 mmol/L for women) or high triglyceride (triglycerides ≥1.7 mmol/L)
    5. Both low HDL cholesterol (≤1.03 mmol/L for men and ≤1.29 mmol/L for women) AND high triglyceride (triglycerides ≥1.7 mmol/L)
    6. Diagnosed or known case of polycystic ovarian syndrome.
  8. Female participants of child-bearing potential (all those below 55 years except if they are surgically sterile, meaning they have undergone a hysterectomy, bilateral tubal ligation, or bilateral oophorectomy, or formally diagnosed by their doctors to be post-menopausal) must agree to use the acceptable methods of contraception from the time of consent until last follow up visit.
  9. Participant is able to communicate satisfactorily with the Investigator and Investigation Site staff, and to participate in, and comply with all clinical study requirements.
  10. Participants agrees to have all trial procedures performed and is able and willing to comply with all trial visits and protocol requirements.

Exclusion Criteria:

  1. Participant is unable and unwilling to use the AffeX-CT device daily.
  2. Participant has a small tragus (ie. the size or shape of the tragus is such that it doesn't allow the application of the ear-clips of the AffeX-CT device for a sustained period of time).
  3. Participant has a piercing on the tragus of the ear.
  4. Participant is diagnosed with atrial fibrillation or other form of cardiac arrhythmia
  5. Participant is known to have chronic kidney disease (CKD) stage 3b or higher or had eGFR <45 ml/min/1.73 m2 in last three months prior to baseline (randomisation) visit.
  6. Participant has type 1 diabetes mellitus.
  7. Participant has type 2 diabetes mellitus on Insulin or those on oral antidiabetic medications with poor glycaemic control defined as HbA1c above 8.5% (or >69 mmol/mol).
  8. Participant has a history of falls or symptoms of orthostatic hypotension in the last 3 months prior to baseline (randomisation) visit.
  9. Participant is pregnant, nursing or planning to become pregnant within the next 6 months.
  10. Participant suffers from chronic pain and has taken anti-inflammatory drugs for two or more days per week over the last month prior to baseline (randomisation) visit.
  11. Participant has clinically significant or symptomatic hypertension-mediated target organ damage such as severe heart failure with NYHA 4, end stage renal damage, medically diagnosed/imaging proven stroke, symptomatic peripheral vascular disease, or severe retinopathy.
  12. Participant has a history of stable or unstable angina or had an acute coronary event within 3 months prior to baseline (randomisation) visit or had a myocardial infarction within the last six months of enrolment prior to baseline (randomisation) visit.
  13. Participant has a history of renal denervation within last 1 year prior to baseline (randomisation) visit.
  14. Participant has a therapeutic implantable electronic/electrical device such as pacemaker, implantable cardioverter-defibrillators (ICDs), implanted vagal stimulators.
  15. Participant has history of hospitalization (> 24 hour) for heart failure, or cerebrovascular accidents, or history of stroke diagnosed based on imaging or evidence of specialist diagnosis or any other indirect evidence such as discharge summary or clinical letter (at any time in the past).
  16. Participant has mean daytime ABPM pulse pressure ≥ 80 mmHg at screening or baseline (randomisation) visit.
  17. Participant has a heart rate <50 bpm at screening or baseline (randomisation) visit (measurement taken after 5 minutes of rest in a seated position and when finger probe has been placed for a minimum of 30 seconds thereafter).
  18. Participant has auricular dermatitis.
  19. Participant has postural hypotension, defined as a fall > 20mmHg in SBP on standing at 3 minutes (compared with sitting).
  20. Participant has a history of hospitalization for hypertensive emergency or urgency in the last six months of enrolment prior to baseline (randomisation) visit.
  21. Participant is identified as unsuitable to participate by the CI/Co-Investigator(s) and/or Investigation site team for another reason (e.g., for other medical reasons, laboratory abnormalities, limited life expectancy, etc.).
  22. Participants with history of epilepsy and are currently on anti-epileptic medication or those who are not on any anti-epileptic medication but have history of a seizure within last 10 years.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Active arm
Participants in this arm will receive the active AffeX-CT device.
Device: Active AffeX-CT device
(Trans-cutaneous Autonomic Neurostimulation) tAN treatment will be administered using AffeX-CT device (a device based on a totally TENS unit). AffeX device comprises of a battery-operated control unit, two electrode pairs arranged on ear clips and connected to the control unit with electrical leads. The AffeX device generates an electrical signal that is used to stimulate the nerves that naturally control the output from the sympathetic nervous system.
Sham Comparator: Sham arm
Participants in this arm will receive the sham (inactive) AffeX-CT device.
Device: Sham AffeX-CT device
Sham Totally TENS device. The device is identical to the active device used in the study, but its only purpose is to act as a placebo. The ear-clip electrodes have been modified so that the electric current is not transmitted to the participant.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in average daytime ambulatory Systolic Blood Pressure (SBP) from baseline to the end of treatment.
Time Frame: from baseline to 3 months
Daytime SBP values will be obtained with 24hr ABPM
from baseline to 3 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in average daytime ambulatory SBP and Diastolic Blood Pressure (DBP) from baseline and 1 month.
Time Frame: from baseline to 1 month
Daytime ambulatory SBP values will be obtained with 24hr ABPM
from baseline to 1 month
Change in average daytime ambulatory DBP from baseline to the end of treatment.
Time Frame: from baseline to 3 months
Daytime ambulatory DBP values will be obtained with 24hr ABPM
from baseline to 3 months
Controlled BP at the end of treatment defined as mean daytime ambulatory SBP<135 mmHg and mean daytime ambulatory DBP<85 mmHg.
Time Frame: from baseline to 3 months
Daytime ambulatory SBP and DBP will be obtained with 24hr ABPM
from baseline to 3 months
Change in average 24-hour ambulatory SBP and DBP from baseline to the end of treatment.
Time Frame: from baseline to 3 months
Daytime ambulatory SBP and DBP will be obtained with 24hr ABPM
from baseline to 3 months
Change in average office SBP and DBP from baseline to 1 month, and from baseline to the end of treatment (3 months).
Time Frame: baseline to 1 month and baseline to 3 months
Daytime ambulatory SBP and DBP will be obtained with a vital signs monitor
baseline to 1 month and baseline to 3 months
Change in average daytime ambulatory HR, and in average night-time ambulatory HR from baseline to the end of treatment.
Time Frame: from baseline to 3 months
Daytime and nigh-time ambulatory HR will be obtained with 24hr ABPM
from baseline to 3 months
Change in BP variability defined as the coefficient of variation (SD/mean) of 24-hour ambulatory SBP, and of within-visit office SBP from baseline to the end of treatment.
Time Frame: from baseline to 3 months
24hr ambulatory SBP will be obtained with 24hr ABPM
from baseline to 3 months
Change in Heart Rate (HR) variability defined as the coefficient of variation (SD/mean) of 24-hour ambulatory HR, and of within-visit office HR from baseline to the end of treatment.
Time Frame: from baseline to 3 months
24hr ambulatory HR will be obtained with 24hr ABPM
from baseline to 3 months
Occurrence of a serious adverse event (SAE), fatal or non-fatal, within 3 months.
Time Frame: from baseline to 3 months
SAEs will be collected through patient interviews, reporting and monitoring
from baseline to 3 months
The occurrence of a major cardiovascular event (MACE), including myocardial infarction (MI), stroke, and cardiovascular-related mortality within 3 months.
Time Frame: from baseline to 3 months
MACE will be collected through patient interviews, reporting and monitoring
from baseline to 3 months
Change in Quality of life between baseline and the end of the treatment (3 months) using the EuroQol Visual Analogue score (0-100), and the EuroQol 5 Dimension (EQ5D) quality of life (QoL) questions.
Time Frame: from baseline to 3 months
EQ-5D-5L questionnaire
from baseline to 3 months
Change in sleep quality between baseline and the end of the treatment using the Insomnia Severity Index (ISI), a 7-item questionnaire with each question allowing responses on a 5-point Likert scale from 0-4. Responses summed to give an overall score of 0
Time Frame: from baseline to 3 months
ISI questionnaires
from baseline to 3 months
Adherence to trial therapy, assessed as the proportion of days out of total days in follow-up when therapy was self-administered, and the average daily duration of self-administered therapy over the 3 months of follow-up (90 days).
Time Frame: from baseline to 3 months
Study log-book
from baseline to 3 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Queen Mary University of London

Collaborators

Health Innovation Oxford and Thames Valley (Oxford AHSN)

Investigators

  • Principal Investigator: Ajay K Gupta, Queen Mary University of London

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

August 1, 2022

Primary Completion (Actual)

September 8, 2025

Study Completion (Actual)

September 8, 2025

Study Registration Dates

First Submitted

December 16, 2021

First Submitted That Met QC Criteria

December 16, 2021

First Posted (Actual)

January 5, 2022

Study Record Updates

Last Update Posted (Estimated)

November 19, 2025

Last Update Submitted That Met QC Criteria

November 17, 2025

Last Verified

November 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2358563

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

On publication of findings relevant anonymized dataset will be made available to benefit researchers with justifiable reasons

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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