Animal model evaluation of a novel renal denervation system for future laparoscopic treatment of resistant hypertension

Abstract

Although percutaneous catheter-based ablation of renal sympathetic nerve fibers has been used in the treatment of patients with resistant hypertension, a recent phase III study did not confirm its efficacy. In this study, we developed a novel laparoscopic renal denervation system and evaluated its safety and initial feasibility using an animal model. Materials and Methods: A novel surgical instrument that uses a smart algorithm with temperature-monitoring feedback was developed. We used 4 male pigs (6 weeks old, weighing approximately 45 kg each) to evaluate the safety and efficacy of the laparoscopic renal denervation system. We performed immunohistochemical staining analysis after renal denervation using various tip temperatures and over various durations through an open approach. Results: When the temperature of the outer wall of the renal artery was maintained at 90°C for 180 seconds, the artery was completely denervated without damaging its inner layer, as evaluated using Masson's trichrome staining. When the temperature ranged from 70°C to 90°C and the duration ranged from 90 to 420 seconds, partial or complete denervation without significant vessel injury was confirmed with anti-growth-associated protein 43 and anti-S100 staining. Conclusions: This animal study confirmed the safety and feasibility of the novel laparoscopic renal denervation system. A safe and effective protocol was developed with ablation at a constant tissue temperature of 70°C to 90°C within 180 seconds. However, further developments are necessary before its clinical use.