Development of Integrated Thermistor Sensor and Heating Electrode for Renal Denervation Procedure

Hypertension is a growing worldwide issue. Patients whom blood pressure level were unable to be brought under control despite the usage of three or more medication is known as resistant hypertension. Resistant hypertension increased the risk of patients developing adverse cardiovascular disease as compared to patients with controlled high blood pressure. The current treatment for resistant hypertension includes minimally invasive catheter based renal denervation procedure. However, there is no procedural endpoint of the ablation of the renal nerve for this renal denervation procedure. In this work, an integrated thermistor sensor with a heating electrode was developed for monitoring of the ablation temperature during the procedure. Thus ensuring proper ablation of the nerve, reducing the risk of damaging the renal nerve and increasing the success rate of the procedure. Bench-top characterization on thermistor resistance output with respect to temperature change and ex-vivo testing on RF ablation using the integrated sensor were performed. Testing result were presented in the paper. An average of 15kohm resistance change (ΔR) in thermistor sensing element from temperature range of 25°C to 90°C. For RF power of 1 W, the ablation scarring size on the tissue was approximately 2mm (length and width) with a depth of 2.5mm depth.