title: Bipolar multi-electrode balloon catheter radiofrequency renal denervation with the Vessix system: preclinical safety evaluation.
abstract: OBJECTIVE
  A bipolar multi-electrode 7 Fr-compatible balloon-catheter radiofrequency (RF) renal denervation system (Vessix™ Renal Denervation System; Boston Scientific, Marlborough, MA, USA) was evaluated for safety in domestic swine.
  
  
  RESULTS
  Renal arteries of 27 swine received overlapping treatments proximally/single treatments distally to mimic balloon overlap clinically. Each histopathology cohort (30, 90, 180 days) had four RF-treated and three sham-treated (no RF energy delivered) animals, with the response of artery/surrounding nerves to bilateral treatment examined (42 arteries). Scanning electron microscopy of the renal artery flow surface for endothelialisation was performed in six additional pigs (three at each of 30 and 90 days: 12 arteries) following unilateral whole artery treatment with proximal overlap: RF one side, sham the other side. Power was ~1 watt, treatment duration 30 seconds, target temperature 68°C. Renal histology and assessment for off-target injury was performed in all 27 swine. Renal artery thermal injury was transmural and segmental involving <10% to >90% of the circumference (typically 30-60%) with segmental neointimal hyperplasia exceeding shams but haemodynamically trivial (maximum stenosis 17.7%). Healing of necrotic arterial media was by replacement fibrosis. Overlying nerves also became fibrotic. Endothelialisation was focally incomplete at 30 days but confluent at 90 days. No off-target injury occurred outside the renal arteries.
  
  
  CONCLUSIONS
  Safety was demonstrated.
authors.affiliation: Division of Pathology, Department of Paediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Wilson
authors.forename: Dawn
authors.initials: D
authors.lastname: Winsor-Hines
authors.forename: Radhika R
authors.initials: RR
authors.lastname: Tunstall
authors.forename: Peter D
authors.initials: PD
authors.lastname: Wilson
authors.forename: Steve P
authors.initials: SP
authors.lastname: Hawley
authors.forename: Mohammad
authors.initials: M
authors.lastname: Eskandarian
authors.forename: Gordana
authors.initials: G
authors.lastname: Svajger
authors.forename: Liza
authors.initials: L
authors.lastname: Davis
authors.forename: Jeannette
authors.initials: J
authors.lastname: Bankes
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Huibregtse
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation*; D006973:Hypertension / Q000601:surgery*; D008855:Microscopy, Electron, Scanning; D008953:Models, Anatomic; D058426:Neointima / Q000473:pathology; D012077:Renal Artery / Q000294:innervation / Q000473:pathology / Q000601:surgery*; D034421:Sus scrofa; D013562:Sympathectomy / Q000295:instrumentation*