Optimal Strategy for HIFU-Based Renal Sympathetic Denervation in Canines

Area of Science:

• Nephrology
• Cardiovascular Medicine
• Medical Devices

Background:

• The relationship between acoustic energy dose and the efficacy/safety of high-intensity focused ultrasound (HIFU) renal sympathetic denervation (RDN) requires further investigation.
• Understanding this relationship is crucial, especially in light of previous trial failures.

Purpose of the Study:

• To determine the optimal acoustic energy dose for effective and safe HIFU-based RDN.
• To investigate the mechanism of RDN failure in the WAVE IV trial by studying dose-response relationships.

Main Methods:

• Thirty canines underwent RDN with varying HIFU energy doses (200-300 W), alongside a sham control group.
• Blood pressure, renal tissue norepinephrine levels, and histological nerve injury were assessed post-procedure.
• Renal artery injury was evaluated to determine safety parameters.

Main Results:

• Significant blood pressure reduction was observed in the 200 W, 250 W, and 300 W groups.
• Histological analysis revealed maximal nerve injury scores in the 200-300 W groups, indicating effective sympathetic denervation.
• While effective, the 300 W group showed significantly higher renal artery injury compared to other doses.

Conclusions:

• RDN efficacy is directly correlated with the delivered acoustic energy dose.
• An energy dose of 200-250 W appears to be the optimal range for effective and safe RDN in canines.
• This finding provides critical insights into optimizing HIFU parameters for RDN procedures.