EUS-guided gastro-enteral anastomosis for the treatment of gastric outlet obstruction: is the end of the enteral stent?

Gastric outlet obstruction (GOO) is characterized by a nonadequate gastric emptying because of a benign or malignant condition. Malignant conditions are more frequent than the benign ones and pancreatic head and gastric antral neoplasia are the most common cause of malignant GOO [1]. In the past years, before the advent of therapeutic endoscopy, the treatment of choice for these patients was represented by the surgical by-pass (SBP) [2], but this intervention was burdened by a significant morbidity (25–35%) and perioperative mortality of about 2%, despite the more common adverse events (AEs) of this intervention is the delayed gastric emptying (DGE) occurring in the 15–30% of these patients [3]. The rates of DGE significatively improved with the advent of laparoscopic surgery, also resulting in an earlier oral feeding and lower hospital stays [4]. Therapeutic endoscopy of the GOO, with the insertion of a duodenal self-expandable metal stent (SEMS), was introduced in the 90s, with favorable short-term results [5] but higher recurrent rate of obstructive symptoms and reintervention in the subsequent months, if compared to the laparoscopic SBP [6]. No difference in terms of mortality is reported between the two groups [7]. It means that, between the two procedures, the SBP should be reserved to the long-survival patients. With the advent of the therapeutic endoscopic ultrasonography (EUS), new endoscopic treatment has been proposed, especially for patients unfit for surgery, and the advent of luminal apposing metal stent (LAMS) with an electrocauteryenhanced tip has increased its potential role. The first report of EUS gastro-enterostomy (EUS-GE) come from Binmoeller et al., in an animal study, showing the potential role of these new frontiers of endoscopy at that time [8]. In this last 10 years, several papers about the EUS-GE were published, underlining its role in the therapeutic field of GOO, both for benign, as afferent loop syndrome, and malignant conditions [9,10]. The published studies about this issue demonstrate, in expert hands, excellent results of the EUS-GE with a reported technical and clinical success of, respectively, 94–97% and 90% with a low rate of AEs [11,12]. Subsequently, comparison studies between EUS-GE vs. SBP and between EUS-GE vs. duodenal SEMS were published. According to endoscopic society of gastrointestinal endoscopy (ESGE) guidelines, endoscopists performing therapeutic endoscopic ultrasound procedures (including EUS-GE) should have adequate experience not only in therapeutic EUS but also in endoscopic retrograde cholangiopancreatography (ERCP) [13]. Moreover, during EUS-GE, endosonographers should consider the availability of surgical and interventional radiology back up in case of AEs. A recent study tried to identify number of cases needed to achieve proficiency and mastery in this procedure, using cumulative sum analysis showing that 25 cases were needed to achieve proficiency and 40 cases to achieve mastery [14]. A recent published retrospective study coming from an American group on 100 consecutive patients and comparing the enteral stenting vs. EUS-GE showed that the rate of stent failure requiring intervention was higher in the SEMS group than the EUS-GE one (32.0% vs. 8.3%, p = 0.021) with a comparable technical success of 100% in both groups. Higher was also the clinical success, in favor of EUS-GE group (95.8% vs. 76.3%, p = 0.042) with a similar hospital stay following the procedure. The long-term follow-up showed less AEs for the EUS-GE group with a decreased stent function in the SEMS group [15]. These results were also reported 2 years before in a smaller retrospective casuistic of 82 patients showing as, on multivariable analysis, the placement of an enteral SEMS was an independent risk factor associated with the need of a subsequent reintervention (OR: 12.8, p = 0.027), during the follow-up period [12]. A more recent and larger propensity score-matched retrospective series comparing EUS-GE and enteral SEMS showed higher clinical success (91% vs. 75%; p = 0.008) and lower stent dysfunction (1% vs. 26%; p < 0.001) of EUS-GE, with similar safety (10% vs. 21%; p = 0.09) [16]. The very low rate of LAMS occlusion can be explained by the fact that the LAMS is a fully covered stent, avoiding the tissue ingrowth inside the meshes of the stent, different to the duodenal SEMS, predominantly uncovered. Additionally, the