Impact of Renal Pelvic Denervation on Systemic Hemodynamics and Neurohumoral Changes in a Porcine Model.

INTRODUCTION: The blood pressure (BP) response to arterial renal denervation (RDN) is variable. METHODS: This study examined the effectiveness of renal pelvic denervation (RPD) on BP, heart rate (HR), norepinephrine (NE), and histopathology in 42 swine. NE levels were measured immediately, 7, 14, 30, and 90 days after RPD. Intra-arterial BP and HR were measured throughout RPD and after 14 days in 5 swine. RESULTS: During the procedure, RPD immediately reduced systolic BP (-20.6 ± 18.3 mm Hg), diastolic BP (-6.0 ± 8.3 mm Hg), and HR (-5.4 ± 5.6 bpm), which remained decreased at follow-up. The porcine kidneys had a mean NE reduction of 76% directly post procedure and 60% after 7 days, 64% after 14 days, 57% after 30 days, and 65% after 90 days. Histopathological examination confirmed nerve ablation. CONCLUSIONS: These preliminary findings suggest that the renal pelvis nerve ablation is an encouraging target for RDN. Clinical trials are required to test the feasibility of RPD in human hypertension.

A novel non-vascular system to treat resistant hypertension.

AIMS: To evaluate in a preclinical model the utility of a monopolar electrode catheter delivering radiofrequency (RF) energy placed into the renal pelvis in order to treat resistant hypertension (RH). METHODS AND RESULTS: Sixteen female domestic swine weighing 60-65 kg underwent renal pelvic denervation via ureteral access. Three animals were euthanised immediately after delivery of RF energy; five animals were allowed to survive for seven days, six animals were allowed to survive for 14 days and two animals were allowed to survive for 30 days. Renal cortical norepinephrine levels were measured in all groups of animals. Histopathology of the treated zone was performed to confirm nerve damage. Renal cortical tissue was harvested for determination of tissue norepinephrine by HPLC. The kidneys were then profusion-fixed and harvested for histopathologic analysis. Mean reduction of norepinephrine levels was 60.4% compared to control. Histopathology confirmed nerve ablation in the treated zone. CONCLUSIONS: In this small, preclinical study, we introduce a new non-vascular system to treat resistant hypertension. If the current clinical experience confirms efficacy and safety, this approach may be one way to treat patients who cannot be treated with the standard percutaneous arterial devices.