Renal responses to long-term carotid baroreflex activation therapy in patients with drug-resistant hypertension.

Carotid baroreflex activation has been demonstrated to provide enduring reductions in arterial blood pressure. The aim of this study was to investigate the effect of long-term therapy on renal function. A total of 322 patients were enrolled in the Rheos Pivotal Trial. Group 1 consisted of 236 patients who started baroreflex activation therapy 1 month after device implantation, whereas in the 86 patients from group 2 the device was activated 6 months later. Serum creatinine and urine albumin/creatinine ratio were collected at screening (before device activation), and at months 6 and 12. Multilevel statistical analyses were adjusted for various covariables. Serum creatinine increased from 78 to 84 mu mol/L, and glomerular filtration rate decreased from 92 to 87 mL/min per 1.73 m(2) in group 1 at month 6 (P<0.05). These values did not change any further after 12 months of therapy. Patients with highest glomerular filtration rate showed the greatest decrease in glomerular filtration. Group 2 showed the same trends as group 1 even before device activation at month 6. Systolic blood pressure reduction seemed to be significantly related to the change in glomerular filtration rate in both groups. Albumin/creatinine ratio did not change in both groups during follow-up. In conclusion, baroreflex activation therapy in hypertensive patients is associated with an initial mild decrease in glomerular filtration rate, which may be considered as a normal hemodynamic response to the drop in blood pressure. Long-term treatment does not result in further decrease in renal function, indicating baroreflex activation as a safe and effective therapy.