Dedicated Echoendoscope for Interventional Endoscopic Ultrasound: Comparison with a Conventional Echoendoscope

Background/Objective: Interventional endoscopic ultrasound (I-EUS) is technically difficult and has risks of severe adverse events due to the scarcity of dedicated endoscopes and tools. A new EUS scope was developed for I-EUS and was modified to increase the puncture range, reduce the blind area, and overcome guidewire difficulties. We evaluated the usefulness and safety of a new EUS scope compared to a conventional EUS scope. Methods: All I-EUS procedures were performed at Juntendo University Hospital from April 2020 to April 2022. The primary outcomes included the procedure time and fluoroscopy time. The secondary outcomes included the technical success rate and the rates of procedure-related adverse events. Clinical data were retrospectively reviewed and statistically analyzed between the new and conventional EUS scopes. Results: In total, 143 procedures in 120 patients were analyzed. The procedure time was significantly shorter with the new EUS scope, but the fluoroscopy time was not different. Among the patients only undergoing EUS-guided biliary drainage (EUS-BD), 79 procedures in 74 patients were analyzed. Both the procedure time and fluoroscopy time were significantly shorter with the new EUS scope. Multivariate analysis revealed that a new EUS scope and use of covered metal stents could reduce the fluoroscopy time. The technical success rate and the adverse event rate were not significantly different between the total I-EUS and the EUS-BD only groups. However, the conventional scope showed stent deviation during stent placement, which did not happen with the new scope. Conclusions: The new EUS scope reduced procedure time for total I-EUS and fluoroscopy time for EUS-BD compared to a conventional EUS scope because of the improvement suitable for I-EUS.