3 The procedure
3.1 Implanting a baroreceptor stimulation device for resistant hypertension aims to lower blood pressure by electrically stimulating the carotid baroreflex, which controls blood pressure by regulating autonomic nervous activity. Both unilateral and bilateral devices have been used. The unilateral device consists of an electrode placed on 1 of the carotid sinuses and a battery-powered implantable generator. Device programming allows the frequency, amplitude and pulse-width of stimulation to be adjusted and it is programmable by time of day.
3.2 The procedure is usually done with the patient under general anaesthesia or conscious sedation. The pulse generator is implanted under the skin near the clavicle. With the unilateral device, a button electrode is sutured to 1 carotid sinus and a thin wire conducts electrical energy from the implantable pulse generator to the carotid sinus. Intraoperative testing is used to determine the optimal placement of the electrode for the best haemodynamic response. An earlier version of the device was bilateral, using 2 leads with electrodes wrapped around both carotid sinuses.
3.3 The device is usually activated about a month after implantation. Clinic staff adjust therapy settings, such as the frequency, amplitude and pulse-width of stimulation, using wireless communication when the patient attends hospital for follow-up appointments. The device can be turned off by clinic staff if necessary.