Radiofrequency ablation of renal sympathetic nerve: Numerical simulation and ex vivo experiments

Renal sympathetic denervation is regarded as a new effective method in the treatment of resistant hypertension, but in the therapeutic temperature and complications, it has some controversy. The aim of this study was to calculate the multi-physical field for radiofrequency ablation and verify its feasibility and effectiveness with ex vivo experiments. The temperature distribution and flow field in the renal artery were analyzed by finite element method and verified by ex vivo experiments with an equivalent model. After ablating in simulation, the center temperature of the renal artery reached the therapeutic target which is 43°C (about 48°C). When increasing the time or changing the velocity, variations in the temperature ranged within 2°C. In the ex vivo experiments, the highest temperature under different conditions increased from 4.12°C to 9.61°C. Within the range of the normal velocity, that is, 8 W power output, the therapeutic purpose (Δ T ≥ 6°C) was achieved and effect on the blood and peripheral tissues was less. The temperature field has influences on the choices of treatment parameters with different degrees. The energy output is the most influential factor, while ablation time and flow velocity have less effects on the temperature field. This study preliminarily verified the safety and effectiveness of the renal sympathetic denervation.