Implantable carotid sinus stimulator for the treatment of resistant hypertension: local effects on carotid artery morphology.
BACKGROUND
The Rheos System is a chronically implanted carotid sinus baroreflex activating system with a pulse generator and bilateral perivascular carotid sinus leads (CSLs) that is being evaluated in prospective clinical trials for the treatment of drug-resistant hypertension. We evaluated carotid artery structural integrity after implantation of the CSLs.


METHODS
To assess the effect of chronic CSL attachment, 29 CSLs were implanted on the common carotid arteries of eight sheep. The studies were terminated at 3 and 6 months postimplantation to assess anatomic and histologic changes. Additionally, 10 patients with resistant hypertension were enrolled in the Rheos Multicenter Feasibility Trial. Duplex ultrasound (DUS) was performed before device implantation and at 1 and 4 months postimplantation in this patient cohort. An independent core laboratory assessed all DUSs.


RESULTS
Ovine carotid angiography revealed no significant stenoses, while anatomic and histologic evaluations demonstrated electrode encapsulation in a thin layer of connective tissue with no evidence of stenosis, erosion, or inflammation. DUS evaluation revealed no significant increase in peak systolic velocities of the common and internal carotid arteries 1 and 4 months after initial implantation, indicating a lack of injury, remodeling, or stenosis.


CONCLUSIONS
The current data suggest that the CSLs used with the Rheos System are not associated with the development of carotid stenosis or injury. These short-term data support the concept of CSL placement and merit long-term investigation in a larger multicenter prospective trial.
Sanchez
Luis A
LA
Division of Vascular Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, MO 63110, USA. sanchezl@wustl.edu
Illig
Karl
K
Levy
Mark
M
Trachiotis
Gregory
G
Shanley
Charles
C
Irwin
Eric
E
Jim
Jeffrey
J
Rossing
Martin
M
Kieval
Robert
R
D000328:Adult; D000368:Aged; D000818:Animals; D000959:Antihypertensive Agents / Q000627:therapeutic use; D017704:Baroreflex; D001794:Blood Pressure; D002346:Carotid Sinus / Q000000981:diagnostic imaging / Q000294:innervation* / Q000473:pathology; D004351:Drug Resistance; D004359:Drug Therapy, Combination; D004599:Electric Stimulation Therapy / Q000295:instrumentation*; D004567:Electrodes, Implanted; D004867:Equipment Design; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D023421:Models, Animal; D012756:Sheep; D013997:Time Factors; D016896:Treatment Outcome; D018616:Ultrasonography, Doppler, Duplex; D014481:United States
D000959:Antihypertensive Agents