Long-Term Safety and Efficacy of Transcatheter Microwave and Radiofrequency Denervation in a Chronic Ovine Model

J Am Heart Assoc. 2024 May 7;13(9):e031795. doi: 10.1161/JAHA.123.031795. Epub 2024 Apr 25.


Background: Transcatheter renal denervation (RDN) has had inconsistent efficacy and concerns for durability of denervation. We aimed to investigate long-term safety and efficacy of transcatheter microwave RDN in vivo in normotensive sheep in comparison to conventional radiofrequency ablation.

Methods and results: Sheep underwent bilateral RDN, receiving 1 to 2 microwave ablations (maximum power of 80-120 W for 240 s-480 s) and 12 to 16 radiofrequency ablations (180 s-240 s) in the main renal artery in a paired fashion, alternating the side of treatment, euthanized at 2 weeks (acute N=15) or 5.5 months (chronic N=15), and compared with undenervated controls (N=4). Microwave RDN produced substantial circumferential perivascular injury compared with radiofrequency at both 2 weeks [area 239.8 (interquartile range [IQR] 152.0-343.4) mm2 versus 50.1 (IQR, 32.0-74.6) mm2, P <0.001; depth 16.4 (IQR, 13.9-18.9) mm versus 7.5 (IQR, 6.0-8.9) mm P <0.001] and 5.5 months [area 20.0 (IQR, 3.4-31.8) mm2 versus 5.0 (IQR, 1.4-7.3) mm2, P=0.025; depth 5.9 (IQR, 1.9-8.8) mm versus 3.1 (IQR, 1.2-4.1) mm, P=0.005] using mixed models. Renal denervation resulted in significant long-term reductions in viability of renal sympathetic nerves [58.9% reduction with microwave (P=0.01) and 45% reduction with radiofrequency (P=0.017)] and median cortical norepinephrine levels [71% reduction with microwave (P <0.001) and 72.9% reduction with radiofrequency (P <0.001)] at 5.5 months compared with undenervated controls.

Conclusions: Transcatheter microwave RDN produces deep circumferential perivascular ablations without significant arterial injury to provide effective and durable RDN at 5.5 months compared with radiofrequency RDN.

Keywords: blood pressure; microwave; radiofrequency; renal denervation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Comparative Study

MeSH terms

  • Animals
  • Blood Pressure / physiology
  • Catheter Ablation / adverse effects
  • Catheter Ablation / methods
  • Disease Models, Animal
  • Female
  • Kidney* / blood supply
  • Kidney* / innervation
  • Microwaves* / adverse effects
  • Microwaves* / therapeutic use
  • Radiofrequency Ablation / adverse effects
  • Radiofrequency Ablation / methods
  • Renal Artery* / innervation
  • Sheep
  • Sympathectomy* / adverse effects
  • Sympathectomy* / methods
  • Time Factors