In Silico and in Vitro Development of a New Bipolar Radiofrequency Ablation Device for Renal Denervation

Background: Renal denervation with radiofrequency ablation has become an accepted treatment for drug-resistant hypertension. However, there is a continuing need to develop new catheters for high-accuracy, targeted ablation. We, therefore, developed a radiofrequency ablation device with a basket catheter and bipolar electrodes for controlled, targeted ablation through Joule heating induction between 60°C and 100°C. Methods: : Finite element modeling was used to determine the optimum catheter design to deliver a minimum ablation zone of 4 mm (W) x 10 mm (L) x 4 mm (H) within 60 seconds with a 500 kHz, 60 Vp-p signal, and 0.9 W maximum. The computational model was validated using in vitro phantom tissue impregnated with a color-changing thermochromic pigment. Results: : The in vitro ablation zone closely matched the size and shape of the simulated area. The new electrode design directs the current density towards the artery walls and tissue, reducing unwanted blood temperature increases by focusing energy on the ablation zone. In contrast, the basket catheter design does not block renal flow during renal denervation. Conclusions: : This computational model of radiofrequency ablation can be used to estimate renal artery ablation zones for highly targeted renal denervation in patients with resistant hypertension. Furthermore, this innovative catheter has short ablation times and the lowest power requirement of existing designs to perform the ablation.