Therapeutic Endoscopic Ultrasound: Current Indications and Future Perspectives

The transcendence of endoscopic ultrasound (EUS) from diagnostic to therapeutic tool has revolutionized management options in the field of gastroenterology. Through EUS-guided methods, pancreaticobiliary obstruction can now be utilized as an alternative to surgical and percutaneous approaches. This modality also allows for gallbladder drainage in patients who are not ideal operative candidates. By utilizing its unique imaging capabilities, EUS also allows for drainage access points in cases of gastric outlet obstruction as well as windows to ablate pancreatic cystic lesions. As technical progress continues to evolve, interventional gastroenterology continues to push the envelope of minimally invasive therapeutic procedures in a multidisciplinary setting. In this comprehensive review, we set out to describe current indications and innovations through EUS.

Endoscopic ultrasound in the management of acute cholecystitis

Endoscopic ultrasound-guided gallbladder drainage (EUS-GBD) is increasingly utilised for patients with acute cholecystitis who are high-risk candidates for surgery. The technique to perform EUS-GBD has evolved and matured over the last two decades since EUS-GBD was first described in 2007 using a nasobiliary catheter. Compared to percutaneous gallbladder drainage (PT-GBD), EUS-GBD offers benefits of shorter hospitalisation stay and lesser procedural pain and need for reintervention. The purpose of this review is to provide an updated review of the equipment and techniques available for EUS-GBD, outcomes of the procedure and how it compares against endoscopic transpapillary drainage (ET-GBD), PT-GBD and laparoscopic cholecystectomy. Controversies surrounding the procedure will also be discussed.

Emergent endoscopic ultrasound-guided cholecystoduodenostomy does not prevent R0 resection in a pancreaticoduodenectomy for pancreatic cancer

Endoscopic ultrasound-guided biliary drainage, mainly choledochoduodenostomy, is commonly used as rescue therapy after Endoscopic Retrograde Cholangiopancreatography (ERCP) in malignant distal biliary obstruction due to un-resectable pancreatic cancer. An alternative when the cystic duct is patent and choledochoduodenostomy is not feasible is performing an Endoscopic Ultrasound-gallbladder drainage. The advent of the Lumen Apposing Metal Stents (LAMS) has shortened and simplified this procedure. However, many concerns exist about the performance of these procedures with metal stents preoperatively in resectable tumors. The evidence about Endoscopic Ultrasound-gallbladder drainage before surgery of pancreatic cancer is scarce. An emergent Endoscopic Ultrasound (EUS)-gallbladder drainage (cholecysto-duodenostomy) was performed due to acute cholangitis in the setting of a resectable pancreatic tumor. Surgery after neoadjuvant therapy was done three months later. A complete resection of tumor was feasible. EUS-guided gallbladder drainage using LAMS does not preclude performing a complete resection of a pancreatic head tumor.

Endoscopic transmural drainage tailored to quantity of necrotic debris versus laparoscopic transmural internal drainage for walled-off necrosis in acute pancreatitis: A randomized controlled trial

BACKGROUND AND AIMS

Both endoscopic and laparoscopic transmural internal drainage are practiced for drainage of walled-off necrosis (WON) following acute pancreatitis (AP) but the superiority of either is not established. Our aim was to compare transperitoneal laparoscopic drainage with endoscopic drainage using either lumen apposing metal stents (LAMS) or plastic stents tailored to the amount of necrotic debris in WON.

METHODS

In a randomized controlled trial, adequately powered to exclude the null hypothesis, patients with symptomatic WON were randomized to either endoscopic or laparoscopic drainage. In the endoscopy group, two plastic stents were placed if the WON contained <1/3rd necrotic debris and a LAMS was placed if it was >1/3rd. Primary outcome was resolution of WON within 4 weeks without re-intervention for secondary infection. Secondary outcome was overall success (resolution of WON at 6 months) and adverse events.

RESULTS

Forty patients were randomized: 20 to each group. Baseline characteristics were comparable between the groups. Primary outcome was similar between the groups [16 (80%) in laparoscopy and 15 (75%) in endoscopy group; p = 0.89]. The overall success was similar [18 (90%) in laparoscopy vs. 17 (85%) in endoscopy; p = 0.9]. Median duration of hospital stay was shorter in endoscopy group [4 (4-8) vs. 6 days (5-9); p = 0.03]. Adverse events were comparable between the groups.

CONCLUSION

Laparoscopic drainage was not superior to endoscopic transmural drainage with placement of multiple plastic stent or LAMS depending on the amount of necrotic debris for symptomatic WON in AP. The hospital stay was shorter with the endoscopic approach.

Alternative uses of lumen apposing metal stents

The advent of lumen apposing metal stents (LAMS) has revolutionized the management of many complex gastroenterological conditions that previously required surgical or radiological interventions. These procedures have garnered popularity due to their minimally invasive nature, higher technical and clinical success rate and lower rate of adverse events. By virtue of their unique design, LAMS provide more efficient drainage, serve as conduit for endoscopic access, are associated with lower rates of leakage and are easy to be removed. Initially used for drainage of pancreatic fluid collections, the use of LAMS has been extended to gallbladder and biliary drainage, treatment of luminal strictures, creation of gastrointestinal fistulae, pancreaticobiliary drainage, improved access for surgically altered anatomy, and drainage of intra-abdominal and pelvic abscesses as well as post-surgical fluid collections. As new indications of endosonographic techniques and LAMS continue to evolve, this review summarizes the current role of LAMS in the management of these various complex conditions and also highlights clinical pearls to guide successful placement of LAMS.

Lumen apposing metal stents in drainage of pancreatic walled-off necrosis, are they any better than plastic stents? A systematic review and meta-analysis of studies published since the revised Atlanta classification of pancreatic fluid collections

Lumen-apposing metal stents (LAMS) are increasingly being used in the drainage of pancreatic walled-off necrosis (WON). Best choice of stent is subject to argument, and studies are varied in the reported outcomes between LAMS and plastic stents (PS) to this end. We conducted a comprehensive search of multiple electronic databases and conference proceedings including PubMed, EMBASE, and Web of Science databases (earliest inception through July 2018) to identify studies that reported on the use of LAMS and PS in WON drainage. Studies published since the release of the revised Atlanta classification for pancreatic fluid collections (2014 to current) were included in the analysis. The outcomes were to estimate and compare the pooled rates of clinical success, and adverse-events. A total of 9 studies (737 patients) for LAMS and 6 studies (527 patients) for PS were included in the analysis. The pooled rate of clinical-success with LAMS was 88.5% (95% CI 82.5-92.6, I² = 71.7) and with PS was 88.1% (95% CI 80.5-93.0, I² = 78.1) and the difference was not statistically significant, P = 0.93. No difference was noted in the pooled rates of all adverse-events, LAMS: 11.2% (6.8-17.9, I² = 82.0); vs PS: 15.9% (8.4-27.8, I² = 78.8); P = 0.38. Based on our meta-analysis, LAMS and PS demonstrate equal clinical outcomes and equal adverse-events in the drainage of pancreatic WON.

De-novo Gastrointestinal Anastomosis with Lumen Apposing Metal Stent

Gastric outlet obstruction, afferent or efferent limb obstruction, and biliary obstruction among patients with altered anatomy often require surgical intervention which is associated with significant morbidity and mortality. Endoscopic dilation for benign etiologies requires multiple sessions, whereas self-expandable metal stents used for malignant etiologies often fail due to tumor in-growth. Lumen apposing metal stents, placed endoscopically with the intent of creating a de-novo gastrointestinal anastomosis bypassing the site of obstruction, can potentially achieve similar efficacy, with a much lower complication rate. In our study cohort (n=79), the composite technical success rate and clinical success rate was 91.1% (72/79) and 97.2% (70/72), respectively. Five different techniques were used: 43% (34/79) underwent the balloon-assisted method, 27.9% (22/79) underwent endoscopic ultrasound-guided balloon occluded gastro-jejunostomy bypass, 20.3% (16/79) underwent the direct technique, 6.3% (5/79) underwent the hybrid rendezvous technique, and 2.5% (2/79) underwent natural orifice transluminal endoscopic surgery (NOTES)-assisted procedure. All techniques required an echoendoscope except NOTES. In all, 53.2% (42/79) had non-cautery enhanced Axios stent, 44.3% (35/79) had hot Axios stent, and 2.5% (2/79) had Niti-S spaxus stent. Symptom-recurrence was seen in 2.8%, and 6.3% had a complication (bleeding, abdominal pain or peritonitis). All procedures were performed by experts at centers of excellence with adequate surgical back up.