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arterial pressure and reduced plasma norepinephrine concentration. Assessment of
acute electric baroreflex activation was done in 11 patients undergoing elective
carotid surgery. Significant voltage-dependent blood pressure reduction was
observed (SBP was reduced by 18 mmHg and DBP by 8 mmHg).
For clinical use of BAT, the Rheos system was developed. This system is com-
posed of implantable pulse generator with two electrodes attached bilaterally to
carotid sinuses. The multicenter Rheos feasibility trial that included ten hyperten-
sive patients [ 20 ] was designed to assess safety, device performance, and protocol
parameters of the Rheos system in patients with resistant hypertension. The surgical
procedure was successful in all cases. Generator discharge resulted in acute, energy
dose-depended SBP decrease of 41 mmHg. No significant bradycardia was
observed. BAT using Rheos system results not only in decreased blood pressure but
also leads to the reduction of MSNA and both decrease of plasma norepinephrine
and renin concentrations. Scheffers et al. confirmed short- and long-term antihyper-
tensive effect of BAT. Forty-five patients with resistant hypertension were involved
in the Device-Based Therapy Hypertension Trial (DEBuT-HT). Blood pressure
decreased from SBP 179 to 158 mmHg and DBP from 105 to 93 mmHg after 3
months of BAT was found. Further reduction of blood pressure (SBP to 146 mmHg
and DBP to 83 mmHg) was observed after 2 years of BAT. It should be stressed,
however, that in this clinical study with Rheos system, eight patients experienced
serious adverse effects related to the procedure or related to the device [ 21 ].
The double-blind, randomized, placebo-controlled Rheos Pivotal Trial involved
265 hypertensive patients [ 22 ]. Patients were randomized to Group A and Group
B. The difference in the two groups was period of delayed device activation (1
month after the implantation in Group A and after 7 months in Group B). It was
shown that 42% subjects from Group A and 24% subjects from Group B reached the
target SBP ≤ 140 mmHg after 6 months BAT. The vast majority of subjects (~81%)
benefits of SBP reduction over 10 mmHg.
The second-generation BAT systems is Barostim neo. The main differences
between Barostim and previously used Rheos system are unilateral carotid sinus
activation and largely reduced electrode size. The device consists of one lead elec-
trode and pulse generator controlled with computer system via radiofrequency
telemetry. The device was tested in a single-arm, open-label, nonrandomized study
that included 30 patients with refractory hypertension. The blood pressure reduction
observed during 6 months observation (SBP reduced by 26 mmHg and DBP by 12
mmHg) was comparable to those achieved previously with bilateral baroreflex acti-
vation. It is worth noted that this procedure and system seems to be safe. There were
no related to the procedure or device adverse effects in 90% of subjects [ 23 ]. Recent
research confirms the effectiveness of BAT for the treatment of resistant arterial
hypertension [ 24 ].
Results of the abovementioned studies suggest that BAT with the use of Barostim
neo is not only effective antihypertensive therapy but also seems to be safe
procedure.
M. Adamczak et al.