Direct carotid sinus nerve stimulation in anesthetized human subjects

Area of Science:

• Cardiovascular Science
• Neurosurgery
• Medical Devices

Background:

• Uncontrolled hypertension (HTN) incidence is rising globally, necessitating novel therapeutic strategies.
• Direct carotid sinus nerve (CSN) stimulation may reduce blood pressure (BP), but clinical efficacy with current electrodes is inconsistent.
• Existing electrode technologies have limitations in demonstrating consistent clinical efficacy for CSN stimulation in humans.

Purpose of the Study:

• To investigate the acute effects of direct CSN stimulation on BP and HR in anesthetized humans.
• To evaluate the efficacy of a novel multi-contact electrode and surgical approach for CSN stimulation.
• To assess the dose-dependency of CSN stimulation on BP and HR reduction.

Main Methods:

• A custom, application-specific multi-contact electrode was implanted around CSN branches in anesthetized adults via a novel surgical approach.
• Functional mapping identified presumed baroafferent fibers for stimulation.
• Changes in systolic BP (SBP), diastolic BP (DBP), and heart rate (HR) were measured using multi-level modeling.

Main Results:

• CSN stimulation resulted in a significant maximum drop in SBP (24 ± 20 mmHg) and DBP (11 ± 9 mmHg), with a concurrent HR decrease (10 ± 9 bpm).
• Subjects with higher baseline SBP (>120 mmHg) experienced a greater SBP reduction (31 ± 23 mmHg) compared to those with lower baseline SBP.
• BP and HR returned rapidly to baseline levels upon cessation of stimulation, and a positive dose-response relationship was suggested.

Conclusions:

• Direct CSN stimulation using a novel electrode and surgical technique effectively reduced BP and HR in anesthetized humans.
• The findings indicate a potential new therapeutic avenue for managing hypertension.
• Rapid recovery of BP and HR upon stimulus withdrawal suggests a controllable and potentially safe intervention.