Clinical Research in Cardiology

, Volume 100, Issue 12, pp 1095–1101

Catheter-based renal sympathetic denervation: chronic preclinical evidence for renal artery safety

  • Marian K. Rippy
  • Denise Zarins
  • Neil C. Barman
  • Andrew Wu
  • Keith L. Duncan
  • Christopher K. Zarins
Original Paper

DOI: 10.1007/s00392-011-0346-8

Cite this article as:
Rippy, M.K., Zarins, D., Barman, N.C. et al. Clin Res Cardiol (2011) 100: 1095. doi:10.1007/s00392-011-0346-8

Abstract

Background

Renal sympathetic hyperactivity is associated with hypertension, a leading cause of mortality worldwide. Renal sympathetic denervation via the Symplicity Catheter System has been shown to decrease blood pressure by 33/11 mmHg by 6 months, with no radiofrequency (RF)-related adverse sequelae visible by CT/MR angiography or renal duplex ultrasound 6 months after the procedure. Here, we present preclinical work predating those clinical results. We performed therapeutic renal sympathetic denervation in a swine animal model to characterize the vascular safety and healing response 6 months after renal denervation therapy.

Methods

In December 2007, seven domestic swine received a total of 32 radiofrequency ablations via the Symplicity Catheter System and were euthanatized 6 months later. Renal angiography was done before, immediately after, and 6 months after procedure. The renal vessels were examined histologically with H&E and Movat pentachrome stains to identify evidence of vascular and neural injury. The kidneys and urinary system were also examined for evidence of gross and microscopic abnormalities.

Results

Renal nerve injury involved primarily nerve fibrosis, replacement of nerve fascicles with fibrous connective tissue, and thickening of the epineurium and perineurium. Renal arterial findings included fibrosis of 10–25% of the total media and underlying adventitia, with mild disruption of the external elastic lamina. No significant smooth muscle hyperplasia or inflammatory components were observed. There was no renal arterial stenosis or thrombosis observed by angiography or histology. No gross or microscopic device-related abnormalities were noted in the kidney, surrounding stroma, or urinary bladder.

Conclusions

In a swine model, renal denervation via the Symplicity Catheter System resulted in no clinically significant adverse renal artery or renal findings 6 months after the procedure. This is corroborated by the vascular safety profile demonstrated in subsequent human clinical studies.

Keywords

Radiofrequency ablation Hypertension Renal artery Nerves 

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Marian K. Rippy
    • 1
    • 5
  • Denise Zarins
    • 2
  • Neil C. Barman
    • 2
  • Andrew Wu
    • 2
  • Keith L. Duncan
    • 3
  • Christopher K. Zarins
    • 4
  1. 1.Rippy Pathology SolutionsWoodburyUSA
  2. 2.Medtronic ArdianMountain ViewUSA
  3. 3.Peninsula Pathology Medical GroupSouth San FranciscoUSA
  4. 4.Stanford UniversityStanfordUSA
  5. 5.WoodburyUSA

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