A sham-controlled randomised trial evaluating the safety, acceptability, and efficacy of autonomic neuromodulation using transcutaneous vagal sensory stimulation in uncontrolled hypertensive patients: rationale and study design of the SCRATCH-HTN study

Background: Despite the broad availability of antihypertensive drugs, approximately 40% of hypertensive patients fail to achieve the recommended blood pressure (BP) levels and may require alternative treatment(s). At present, renal denervation is the only proven non-pharmacological device-based alternative treatment available, but it is a costly, invasive, hospital-based procedure that is unlikely to be widely available. Transcutaneous autonomic neuromodulation (tAN)-if shown to be safe, acceptable, and efficacious-can offer a non-invasive, inexpensive, self-administered device-based innovative adjunct or alternative to pharmacological therapy. Methods: SCRATCH-HTN is a double-blind, sham-controlled trial, with 63 participants randomised on a 2:1 basis to receive either tAN or sham-tAN treatment. Hypertensive patients on medication were included if they had elevated systo-diastolic BPs on daytime ambulatory BP monitoring (ABPM) [systolic BP (SBP) of ≥135 and