Partially covered vs Fully covered metal stent for endoscopic ultrasound guided hepatico-enterostomy: A randomized control trial

Biliary obstruction remains one of the most cause for increasing morbidity in patients with carcinoma pancreas, carcinoma gall bladder, cholangiocarcinoma or peri-ampullary carcinoma. Various methods including endoscopic retrograde cholangio-pancreatography (ERCP), endoscopic ultrasound guided biliary drainage (EUS-BD), percutaneous transhepatic biliary drainage (PTBD) etc. can be used. Though traditionally, ERCP was used as a first line modality for drainage of obstructed biliary system, in around 15% to 20% of patients, ERCP attempt gets failed either due to concurrent gastric outlet obstruction or due to difficult biliary canulation. In recent times, EUS guided biliary drainage has emerged as a feasible option in this difficult cases. In a recent meta-analysis, it has shown to be associated with better clinical success (OR, .45; 95% CI, .23-.89; I2 = 0%), fewer postprocedure adverse events (OR, .23; 95% CI, .12-.47; I2 = 57%), and lower rate of reintervention (OR, .13; 95% CI, .07-.24; I2 = 0%) compared to PTBD. Amongst EUS guided biliary drainage, EUS guided hepatico-gastrostomy is feasible even in hilar block as well as in presence of gastric outlet obstruction along with lower rates of stent dysfunction compared to EUS guided choledochoduodenostomy. Technique of EUS guided hepatico-gastrostomy has also undergone more standardised in last decade with better clinical outcomes and lower adverse event rates. Regarding stent selection, dedicated partially covered stent was developed to prevent the blockage of side branches of the biliary ducts. However, the uncovered portion is associated with risk of tissue hyperplasia, stent block by biliary stasis or by food obstruction. Despite initial retrospective studies has shown reduction in risk of segmental cholangitis, risk of recurrent stent obstruction remains high. Recently, Cho S H et al., did a propensity matched analysis of two different types of stent which are being used in EUS guided hepatico-gastrostomy. In that study, patients in whom fully covered stent was used had higher stent patency (76%) compared to patients in whom partially covered metal stent (43%) was used (p=0.03). Moreover, patients in fully covered group required less re-interventions compared to patients in partially covered group (20% vs 38%; p=0.084).(7) However, in absence of any dedicated prospective study, we are planning to perform a randomized controlled trial comparing fully covered vs partially covered metal stent in patients undergoing EUS guided hepatico-gastrostomy.