Preliminary study for development of a new implantable nerve cooling system for hypertension

Hypertension patients are facing at greater risk of developing vascular diseases, such as cardiac disease or cerebrovascular events. Despite various pharmaceutical treatment strategies, about 30% of the patients might have difficulties to maintain the desired level of blood pressure (BP). More than 90% of hypertensive subjects are estimated to be with the essential hypertension which is primarily caused by enhanced sympathetic nerve activity [1]. Catheter-based renal sympathetic denervation (RSDN) has been applied to treat those patients in drug-resistant hypertension. However, the occurrence of the effective outcome by renal denervation being low-level radio frequency energy through the renal arterial wall did not meet the feasible endpoint. In this study, we developed a cooling device that directly and reversibly eliminate the excess nerve interactions in the BP control system of living organisms. The cooling device consists of a Peltier module and a heat pipe. To evaluate the feasibility of this device, we established an assessment model using a goat (n=6) with a left ventricular assist device (LVAD). With this model, we were able to replicate the experimental condition more accurately such as BP than using drugs. It is turn to enables us to analyze renal nerve activity (RNA) amplitude at cooling by cooling device or control condition. As a main result, the cooling device reduced over 60% of integrated RNA compare to control. Moreover, RNA had recovered after cooling renal nerve for about 120 sec. Therefore, our study revealed the controllability and thermodynamic reversal characteristics in animal model.