title: Acute on/off effects and chronic blood pressure reduction after long-term baroreflex activation therapy in resistant hypertension.
abstract: BACKGROUND
  Baroreflex activation therapy (BAT) by electrical stimulation of baroreceptors at the carotid sinus is a promising therapeutic approach to reduce elevated blood pressure (BP). To assess the efficacy of long-term BAT, we investigated acute BP alterations after device deactivation and reactivation (on/off effects) in patients on chronic BAT, as well as chronic BP reductions.
  
  
  METHODS
  Resistant hypertension patients (n = 17) were enrolled in an open-label, single-arm evaluation of unilateral BAT after exclusion of secondary hypertension. Initial eligibility criteria were SBP≥  140 mmHg, despite stable medical therapy with at least three antihypertensive drugs including at least one diuretic. For on/off testing, several office cuff BP measurements were performed: at rest with activated device, 4-6 min after deactivation, and 4-6 min after reactivation.
  
  
  RESULTS
  Before BAT, mean office cuff BP was 179 ± 25 over 98 ± 18 mmHg. At the time of on/off testing (15.1 ± 8.7 months after initial activation and before deactivation), BP was reduced to 147 ± 29 over 84 ± 20 mmHg. On deactivation, SBP increased to 158 ± 38 mmHg (P = 0.004) and DBP to 89 ± 23 mmHg (P = 0.04). After reactivation, SBP decreased to 144 ± 34 mmHg (P = 0.002 vs. deactivation) and DBP to 83 ± 23 mmHg (P = 0.009). There was no correlation between duration of chronic BAT and systolic or diastolic acute on/off response.
  
  
  CONCLUSIONS
  Unilateral BAT reduces BP in patients with resistant hypertension in the long term. There is a significant on/off effect on BP, supporting the efficacy of BAT. The acute on/off response to BAT does not depend on treatment duration. Thus, no evidence of tolerance over time to chronic BAT was found.
authors.affiliation: aDepartment of Internal Medicine III, Heart Center bDepartment of Radiology cDepartment of Cardiac Surgery, Heart Center, University of Cologne, Cologne, Germany dDepartment of Internal Medicine II, University Hospital Salzburg, Salzburg, Austria eDepartment of Internal Medicine 3, Asklepios Hospital Altona, Hamburg, Germany *Marcel Halbach and Tilman Hickethier contributed equally to the writing of this article.
authors.forename: Marcel
authors.initials: M
authors.lastname: Halbach
authors.forename: Tilman
authors.initials: T
authors.lastname: Hickethier
authors.forename: Navid
authors.initials: N
authors.lastname: Madershahian
authors.forename: Hannes
authors.initials: H
authors.lastname: Reuter
authors.forename: Mathias C
authors.initials: MC
authors.lastname: Brandt
authors.forename: Uta C
authors.initials: UC
authors.lastname: Hoppe
authors.forename: Jochen
authors.initials: J
authors.lastname: Müller-Ehmsen
mesh_terms: D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure; D001795:Blood Pressure Determination; D002346:Carotid Sinus / Q000503:physiopathology; D004232:Diuretics / Q000627:therapeutic use; D004599:Electric Stimulation Therapy; D005260:Female; D006801:Humans; D006973:Hypertension / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011311:Pressoreceptors / Q000503:physiopathology*; D019233:Retreatment; D012189:Retrospective Studies; D013997:Time Factors; D017211:Treatment Failure
chemical_list: D000959:Antihypertensive Agents; D004232:Diuretics