New developments in small bowel enteroscopy

New Trends and Advances in Non-Variceal Gastrointestinal Bleeding-Series II

The gastrointestinal tract is a long tubular structure wherein any point in the mucosa along its entire length could be the source of a hemorrhage. Upper (esophagel and gastroduodenal) and lower (jejunum, ileum, and colon) gastrointestinal bleeding are common. Gastroduodenal and colonic bleeding are more frequent than bleeding from the small bowel, but nowadays the entire gastrointestinal tract can be explored endoscopically and bleeding lesions can be locally treated successfully to stop or prevent further bleeding. The extensive use of antiplatelet and anticoagulants drugs in cardiovascular patients is, at least in part, the cause of the increasing number of patients suffering from gastrointestinal bleeding. Patients with these conditions are usually older and more fragile because of their comorbidities. The correct management of antithrombotic drugs in cases of gastrointestinal bleeding is essential for a successful outcome for patients. The influence of the microbiome in the pathogenesis of small bowel bleeding is an example of the new data that are emerging as potential therapeutic target for bleeding prevention. This text summarizes the latest research and advances in all forms of acute gastrointestinal bleeding (i.e., upper, small bowel and lower). Diagnosis is approached, and medical, endoscopic or antithrombotic management are discussed in the text in an accessible and comprehensible way.

EUS-Guided Antegrade Biliary Stenting Using a Novel Fully Covered Metal Stent (with Video)

BACKGROUND

Recently, endoscopic ultrasound (EUS)-guided hepaticogastrostomy (HGS) combined with antegrade stenting (AS) has been reported to be associated with longer stent patency and reduced procedure-related adverse events. In EUS-AS, an uncovered metal stent is usually selected to prevent stent misplacement or dislocation. However, because patient survival has improved with advances in chemotherapy, longer stent patency may be required.

AIM

The technical feasibility and safety of EUS-guided transhepatic biliary drainage combined with EUS-AS using a novel covered metal stent were evaluated.

METHODS

Patients with malignant biliary obstruction leading to obstructive jaundice, in whom standard ERCP had failed or was contraindicated, were enrolled in this study between July 2015 and October 2017. As the control group, patients undergoing EUS-AS using an uncovered metal stent were enrolled between October 2014 and June 2015.

RESULTS

A total of 39 patients were enrolled in this study. Among them, EUS-AS using a covered metal stent was performed in 17 patients and using an uncovered metal stent in the remaining 22 patients. Median stent patency including stent dysfunction and patient death was longer in the covered metal stent group (153 days) compared with that of the uncovered metal stent group (108 days) although there were no significant differences (P = 0.06). In only cases with stent dysfunction was median stent patency of the covered metal stent group significantly longer than that of the uncovered metal stent group (not available vs 150 days, P = 0.02).

CONCLUSIONS

In conclusion, EUS-guided transluminal biliary drainage combined with EUS-AS using a covered metal stent may be feasible and safe, although the indications for this procedure should be carefully considered.

Hypoxia-induced intestinal barrier changes in balloon-assisted enteroscopy

KEY POINTS

Balloon-assisted enteroscopy (BAE) is an emerging standard procedure by utilizing distensible balloons to facilitate deep endoscopy in the small and large intestine. Sporadic cases of bacteraemia were found after BAE. Balloon distension by BAE caused gut tissue hypoxia. The impact of balloon distension-induced hypoxia on intestinal barriers remains unclear. Murine models of BAE by colonic balloon distension showed that short- and long-term hypoxia evoked opposite effects on epithelial tight junctions (TJs). Short-term hypoxia fortified TJ integrity, whereas long-term hypoxia caused damage to barrier function. Our data showed for the first time the molecular mechanisms and signalling pathways of epithelial barrier fortification and TJ reorganization by short-term hypoxia for the maintenance of gut homeostasis. The findings suggest avoiding prolonged balloon distension during BAE to reduce the risk of hypoxia-induced gut barrier dysfunction.

ABSTRACT

Balloon-assisted enteroscopy (BAE) is an emerging standard procedure that uses distensible balloons to facilitate deep endoscopy. Intestines are known to harbour an abundant microflora. Whether balloon distension causes perturbation of blood flow and gut barrier dysfunction, and elicits risk of bacterial translocation remains unknown. Our aims were to (1) conduct a prospective study to gather microbiological and molecular evidence of bacterial translocation by BAE in patients, (2) establish a murine model of colonic balloon distension to investigate tissue hypoxia and intestinal barrier, and (3) assess the effect of short- and long-term hypoxia on epithelial permeability using cell lines. Thirteen patients were enrolled for BAE procedures, and blood samples were obtained before and after BAE for paired comparison. Four of the 13 patients (30.8%) had positive bacterial DNA in blood after BAE. Post-BAE endotoxaemia was higher than the pre-BAE level. Nevertheless, no clinical symptom of sepsis or fever was reported. To mimic clinical BAE, mice were subjected to colonic balloon distension. Local tissue hypoxia was observed during balloon inflation, and reoxygenation after deflation. A trend of increased gut permeability was seen after long-term distension, whereas a significant reduction of permeability was observed by short-term distension in the proximal colon. Human colonic epithelial Caco-2 cells exposed to hypoxia for 5-20 min exhibited increased tight junctional assembly, while those exposed to longer hypoxia displayed barrier disruption. In conclusion, sporadic cases of bacteraemia were found after BAE, without septic symptoms. Short-term hypoxia by balloon distension yielded a protective effect whereas long-term hypoxia caused damage to the gut barrier.

Clinical Impact of the Intra-scope Channel Stent Release Technique in Preventing Stent Migration During EUS-Guided Hepaticogastrostomy

BACKGROUNDS

Stent migration following endoscopic ultrasonography-guided hepaticogastrostomy (EUS-HGS) may sometimes be fatal because there are no adhesions between the biliary tract and stomach. To prevent stent migration and minimize the stent length in the abdominal cavity, we recently performed EUS-HGS using the technique of releasing the stent within the scope channel.

AIMS

To examine the technical feasibility of the intra-scope channel stent release technique.

METHODS

Forty-one consecutive patients who underwent EUS-HGS were enrolled. Between October 2015 and December 2015, EUS-HGS was performed using the extra-scope channel release technique, while the intra-scope channel release technique was performed between January 2016 and March 2016.

RESULTS

The distance between the hepatic parenchyma and the stomach wall after EUS-HGS in the intra-scope channel stent release group was significantly shorter than that in the extra-scope channel release group (0.66 ± 1.25 vs 2.52 ± 0.97, P < 0.05). Adverse events, such as biloma or stent migration, were seen in only the extra-scope channel release group.

CONCLUSION

In conclusion, although additional cases and randomized controlled studies using metal stents of various lengths are needed, our technique is likely to be clinically useful for the prevention of early and late stent migration.

Update in enteroscopy: New devices and new indications

The present review provides an update of the currently available (proto-) types of device-assisted enteroscopy (DAE). In recent years, newly designed double- and single-balloon enteroscopes have emerged. They aim to improve insertion depth into the small bowel, and they also allow more efficient endoscopic interventions. Nowadays, almost all conventional endoscopic procedures are feasible using DAE, opening the door to new indications. Recently, more data have become available on pediatric DAE, DAE-assisted colonoscopy, and DAE in patients with altered anatomy, including DAE-assisted endoscopic retrograde cholangiopancreatography and direct cholangioscopy. Although new enteroscopes are being developed, few comparative studies are available in order to define which DAE suits best for each indication. It is the duty of the international endoscopy community to set up clinical research projects to provide answers to these open questions.