A pilot proof-of-concept study of a modified device for one-step endoscopic ultrasound-guided biliary drainage in a new experimental biliary dilatation animal model

AIM:To evaluate the technical feasibility of a modified tapered metal tip and low profile introducer for onestep endoscopic ultrasound(EUS)-guided biliary drainage(EUS-BD)in a new experimental biliary dilatation porcine model.METHODS:A novel dedicated device for one-step EUS-guided biliary drainage system(DEUS)introducer has size 3F tapered catheter with size 4F metal tip for simple puncture of the intestinal wall and liver parenchyma without graded dilation.A self-expandable metal stent,consisting of both uncovered and nitinol-covered portions,was preloaded into DEUS introducer.After establishment of a biliary dilatation model using endoscopic hemoclips or band ligation with argon plasma coagulation in 9 mini-pigs,EUS-BD using a DEUS was performed following 19-G needle puncture without the use of fistula dilation devices.RESULTS:One-step EUS-BD was technically successful in seven pigs[7/9(77.8%)as intention to treat]without the aid of devices for fistula dilation from the high body of stomach or far distal esophagus to the intrahepatic(n=2)or common hepatic(n=5)duct.Primary technical failure occurred in two cases that did not show adequate biliary dilatation.In seven pigs with a successful bile duct dilatation,the technical success rate was 100%(7/7 as per protocol).Median procedure time from confirmation of the dilated bile duct to successful placement of a metallic stent was 10 min(IQR;8.9-18.1).There were no immediate procedure-related complications.CONCLUSION:Modified tapered metal tip and low profile introducer may be technically feasible for onestep EUS-BD in experimental porcine model.