Abstract
BACKGROUND: Hypertension is a major risk factor for cardiovascular diseases, affecting over 1.28 billion adults worldwide, with nearly 46% remaining undiagnosed or untreated. Auricular vagus nerve stimulation (aVNS) has emerged as a promising non-invasive neuromodulation approach for autonomic regulation, yet its effects on blood pressure (BP) remain underexplored. OBJECTIVE: The effects of aVNS on blood pressure in chronic pain patients were evaluated, with a specific focus on differential responses by hypertensive status and antihypertensive treatment. METHODS: This retrospective dual-center study analyzed the impact of aVNS on BP in 24 chronic pain patients [mean age 48.5 (9.1) years; 75% female], categorized into non-hypertensive (n = 13) and hypertensive (n = 11) individuals. The hypertensive cohort was further stratified into patients receiving pharmacological hypertension treatment (n = 5) and those untreated (n = 6). Patients received aVNS over an 8-week treatment period, followed by a 4-week follow-up. RESULTS: Over an 8-week treatment period, hypertensive patients exhibited significant reductions in systolic BP [-10.7 (2.9) mmHg, p = 0.0003] and diastolic BP [-5.8 (2.0) mmHg, p = 0.0357], while non-hypertensive individuals showed no significant BP changes. Subgroup analysis revealed that BP reductions were most robust and consistent in untreated hypertensive patients (SBP: -11.0 mmHg, p = 0.001), whereas patients on antihypertensive medication showed greater variability. Mean arterial pressure (MAP) declined significantly in hypertensive individuals [-9.3 (6.7) mmHg, p = 0.0022]. In contrast, no significant changes were observed in heart rate or heart rate variability [e.g., heart rate: -0.9 (1.8) beats/min; root mean square of successive differences in normal RR intervals: -12.8 (9.0) ms at week 12, both p = 1.0000], suggesting preserved autonomic stability. CONCLUSIONS: aVNS may be associated with BP reductions in hypertensive patients particularly those not receiving pharmacological treatment, with minimal effects in normotensive individuals. These retrospective findings suggest a potential sustained benefit in patients with comorbid chronic pain and support further investigation through prospective, sham-controlled trials to confirm efficacy and clarify underlying mechanisms.