Impact of Baroreflex Activation Therapy on Renal Function - A Pilot Study

Abstract

Background/Aims: Resistant hypertension and chronic kidney disease (CKD) are interlinked via sympathetic overdrive. Baroreflex activation therapy (BAT) has been shown to chronically reduce blood pressure (BP) in patients with resistant hypertension. The effect of BAT on renal function in CKD patients with resistant hypertension has not been reported. The aim of this study was to investigate the effect of sympathetic inhibition on renal function in CKD patients. Methods: 23 CKD patients with resistant hypertension were prospectively treated with BAT. Analyses were performed before and 6 months after the start of BAT. The renal function was analyzed by creatinine, cystatin C, glomerular filtration rate (GFR), renin, aldosterone, fractioned and 24-hour sodium excretion and analyses of urine marker proteins. The purpose of the control group was to investigate the influence of treating patients in a center for hypertension and regression to the mean on investigated variables. Results: The office mean BP decreased from 116.9 ± 20.9 mm Hg to 104.2 ± 22.2 mm Hg (p < 0.01), while the number of prescribed antihypertensive classes decreased from 6.6 ± 1.6 to 6.1 ± 1.7 (p = 0.02). Proteinuria and albuminuria decreased from a median of 283.9 and 47.7 to 136.5 (p = 0.01) and 45.0 mg/g creatinine (p = 0.01) with pronounced effects in higher CKD stage III + IV compared to I + II (p < 0.01). CKD-EPI cystatin C equation improved from 53.6 ± 22.7 to 60.4 ± 26.1 ml/min (p = 0.02). While creatinine and GFR were impaired after a period of 6 months, no changes of proteinuria, albuminuria, or BP were obtained in control patients. Conclusion: The data of this prospective trial demonstrate potential nephroprotective effects of BAT in therapy-resistant hypertension in CKD patients by a reduction of BP, proteinuria and moreover, a stabilization of estimated GFR.

Effects of Baroreflex Activation Therapy on Ambulatory Blood Pressure in Patients With Resistant Hypertension

“…For BAT, the Barostim neo (CVRx, Minneapolis, MN) was used as described previously. [15][16][17] The BAT device consists of a lead, which is sutured directly on 1-side carotid sinus and a pulse generator implanted in an infraclavicular position in a minimal invasive procedure, including intraoperative testing for optimal placement of the lead for BP response. Thereafter, BAT was initiated 4 weeks after implantation and the stimulation was individually increased by adaption of programmed parameters (pulse amplitude [1-20 mA], pulse width [15-500 ms] and frequency 10-100 pulses/s) during monthly follow-up according to patients' office BP and tolerance.…”

“…Thereafter, BAT was initiated 4 weeks after implantation and the stimulation was individually increased by adaption of programmed parameters (pulse amplitude [1-20 mA], pulse width [15-500 ms] and frequency 10-100 pulses/s) during monthly follow-up according to patients' office BP and tolerance. Follow-up data were acquired as described before [15][16][17] 6 months after starting BAT.…”

“…16 In addition, we analyzed the proportion of responders using the office-based definition (BP reduction of ≥10 mm Hg in office SBP) and the ABPM-based definition (SBP reduction of ≥5 mm Hg in ABPM) separately. All patients provided informed consent before the initiation of protocol-mandated procedures.…”

The sacral parasympathetic system is actually sympathetic—and other updates on recent autonomic research

“…More recently, baroreflex stimulator devices have shown promise in early trials as a means to reduce blood pressure in patients with refractory hypertension [4].…”

Clinical and Physiological Aspects of Salt Sensitive Hypertension

“…seen in small trials, including the setting of CKD [346,347]. Larger and longer trials are needed before the true place of these therapies in the management of resistant hypertension can be known.…”