Pharmacological Modulation of Intrarenal Pressure in a Porcine Model Using a Novel Isoprenaline-Eluting Guidewire

Introduction: Several complications of retrograde intrarenal surgery have been attributed to inadvertent increases in intrarenal pressure. We recently described the development of an innovative isoprenaline-eluting guidewire (IsoWire). The objective of this study was to investigate the impact of this IsoWire on the intrarenal pressure and evaluate its safety. Materials and Methods: This study was performed in 17 renal units using a porcine model. As controls, the intrarenal pressure, heart rate, and mean arterial pressure were measured for a duration of six minutes with a standard guidewire placed in the renal pelvis. For the experiment, the conventional guidewire was substituted with the IsoWire and the same parameters were measured. Blood samples were taken at one-minute intervals to measure plasma isoprenaline levels. This procedure was repeated on the opposite side. Results: The mean intrarenal pressure reduction was 29% (95% CI: 13%-53%). The mean isoprenaline effect time was 174 seconds. No changes in heart rate (p = .908) or mean arterial pressure (p = .749) were recorded after IsoWire insertion. Plasma isoprenaline levels were below the quantitation threshold. Isoprenaline concentrations in the plasma were below the quantification threshold. Ureteroscopy revealed no ureteral lesions. Conclusions: The IsoWire demonstrated a safe and effective reduction of intrarenal pressure. Additional research is necessary to determine whether ureteral smooth muscle relaxation generated by isoprenaline facilitates easier insertion of a ureteral access sheath, decreases the incidence of ureteral access sheath related ureteral lesions, or even encourage the practice of sheathless retrograde intrarenal surgery.