Renal Sympathetic Denervation by Image-Guided Percutaneous Ethanol Injection - Histopathologic Characteristics,...

Area of Science:

• Interventional Radiology
• Nephrology
• Vascular Surgery

Background:

• Renal sympathetic denervation is a therapeutic option for resistant hypertension.
• Chemical denervation offers a minimally invasive alternative to radiofrequency ablation.
• Image guidance is crucial for precise delivery and safety.

Purpose of the Study:

• To evaluate the efficacy and safety of chemical renal denervation via image-guided periarterial ethanol injection in a porcine model.
• To assess the histopathological characteristics of nerve injury and potential side effects.
• To determine the impact on renal tissue norepinephrine concentration.

Main Methods:

• Unilateral renal periarterial ethanol injection performed under MRI guidance in 16 pigs.
• Different ethanol mixtures and volumes were tested (5ml and 10ml ethanol-carbostesin; 10ml ethanol-polyacrylic).
• Histological examination, MRI, MRA, and renal tissue norepinephrine concentration (RTNEC) were assessed post-treatment.

Main Results:

• Histologic evidence of nerve degeneration observed in all treatment groups, with injury depths up to 7.6mm.
• Groups receiving 10ml ethanol-carbostesin (Group II) showed significantly reduced nerve counts and a 53% mean RTNEC reduction (p<0.02).
• No renal artery stenosis was observed; Groups I and III did not show significant RTNEC changes.

Conclusions:

• Image-guided percutaneous periarterial ethanol injection is an effective and safe method for renal denervation.
• The technique allows for nerve injury depth exceeding current radiofrequency ablation probes.
• Optimizing ethanol mixture properties and delivery is critical for maximizing efficacy and minimizing risks.