title: Blood pressure and autonomic responses to electrical stimulation of the renal arterial nerves before and after ablation of the renal artery.
abstract: Radiofrequency (RF) catheter ablation of the renal artery is therapeutic in patients with drug-refractory essential hypertension. This study was designed to examine the role of the renal autonomic nerves and of RF application from inside the renal artery in the regulation of blood pressure (BP). An open irrigation catheter was inserted into either the left or right renal artery in 8 dogs. RF current (17 ± 2 watts) was delivered to one renal artery. Electrical autonomic nerve stimulation was applied to each renal artery before and after RF ablation. BP, heart rate, indices of heart rate variability, and serum catecholamines were analyzed. Before RF ablation, electrical autonomic nerve stimulation of either renal artery increased BP from 150 ± 16/92 ± 15 to 173 ± 21/105 ± 16 mm Hg. After RF ablation, BP increased similarly when the nonablated renal artery was electrically stimulated, although the rise in BP was attenuated when the ablated renal artery was stimulated. Serum catecholamines and sympathetic nerve indices of heart rate variability increased when electrical autonomic nerve stimulation was applied before RF ablation and to the nonablated renal artery after RF ablation, although it changed minimally when the ablated renal artery was stimulated, suggesting interconnectivity between afferent renal nerve stimulation and systemic sympathetic activity. Renal artery angiogram showed no apparent injury after RF ablation. In conclusion, electrical stimulation of the renal arterial autonomic nerves increases BP via an increase in central sympathetic nervous activity. This response might be used to determine the target ablation site and end point of renal artery RF ablation.
authors.affiliation: Graduate School of Health Sciences, Niigata University School of Medicine, 2-746 Asahimachi, Niigata 951-8518, Japan. masaomi@clg.niigata-u.ac.jp
authors.forename: Masaomi
authors.initials: M
authors.lastname: Chinushi
authors.forename: Daisuke
authors.initials: D
authors.lastname: Izumi
authors.forename: Kenichi
authors.initials: K
authors.lastname: Iijima
authors.forename: Katsuya
authors.initials: K
authors.lastname: Suzuki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Furushima
authors.forename: Osamu
authors.initials: O
authors.lastname: Saitoh
authors.forename: Yui
authors.initials: Y
authors.lastname: Furuta
authors.forename: Yoshifusa
authors.initials: Y
authors.lastname: Aizawa
authors.forename: Mitsuya
authors.initials: M
authors.lastname: Iwafuchi
mesh_terms: D000818:Animals; D001341:Autonomic Nervous System / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D002395:Catecholamines / Q000097:blood; D017115:Catheter Ablation; D004285:Dogs; D004558:Electric Stimulation; D006339:Heart Rate / Q000502:physiology*; D012077:Renal Artery / Q000294:innervation* / Q000601:surgery
chemical_list: D002395:Catecholamines