Abstract 14807: Direct Carotid Sinus Nerve Stimulation in Anesthetized Human Subjects

Abstract

Introduction: Drug resistant hypertension is a growing clinical phenomenon across the world and there is a critical need for alternative therapeutic modalities. Hypothesis: A novel multi-contact electrode designed to interface with the carotid sinus nerve in conjunction with a unique implantation technique can selectively activate the baroreflex causing reversible drops in blood pressure (BP) & heart rate (HR) in anesthetized humans. Methods: Patients undergoing therapeutic operations that necessitated carotid bulb exposure were prospectively enrolled in this IRB approved trial. Using a novel surgical approach, an application specific electrode was placed around the CSN followed by contact interface mapping to identify presumed baroafferent fibers which were selectively stimulated. Outcome measures included change in systolic BP (SBP), diastolic BP (DBP), and HR during and after stimulation. Results: 14 subjects met eligibility criteria. In 13, following correct contact identification, stimulation caused a 23±20mmHg (mean±SD) maximum drop in SBP with associated drops in DPB (11±9mmHg), and HR (10±9bpm). All subjects recovered immediately following stimulation withdrawal. All drops were significant (p<0.001, t-test). In subjects with baseline SBP >120mmHg (n=8), maximum SBP drop was 30±23mmHg, while subjects with baseline SBP <120mmHg (n=5) exhibited a maximum SBP drop of 11±3mmHg. There was evidence of a positive dose (current) response relationship. Conclusions: Using a novel surgical approach and electrode, CSN stimulation in anesthetized human subjects caused a marked drop in BP/HR followed by rapid recovery with stimulation withdrawal. There was evidence of dose dependency.