Evaluation of the mechanical properties of current biliary self-expandable metallic stents: axial and radial force, and axial force zero border

Background/Aims@#Mechanical properties (MPs) and axial and radial force (AF and RF) may influence the efficacy and complications of self-expandable metallic stent (SEMS) placement. We measured the MPs of various SEMSs and examined their influence on the SEMS clinical ability. @*Methods@#We evaluated the MPs of 29 types of 10-mm SEMSs. RF was measured using a conventional measurement device. AF was measured using the conventional and new methods, and the correlation between the methods was evaluated. @*Results@#A high correlation in AFs was observed, as measured by the new and conventional manual methods. AF and RF scatterplots divided the SEMSs into three subgroups according to structure: hook-and-cross-type (low AF and RF), cross-type (high AF and low RF), and laser-cut-type (intermediate AF and high RF). The hook-and-cross-type had the largest axial force zero border (>20°), followed by the laser-cut and cross types. @*Conclusions@#MPs were related to stent structure. Hook-and-cross-type SEMSs had a low AF and high axial force zero border and were considered safest because they caused minimal stress on the biliary wall. However, the increase in RF must be overcome.

A Meta-Analysis of Slow Pull versus Suction for Endoscopic Ultrasound-Guided Tissue Acquisition

Background/Aims@#Endoscopic ultrasound (EUS)-guided tissue acquisition is widely utilized as a diagnostic modality for intra-abdominal masses, but there remains debate regarding which suction technique, slow pull (SP) or conventional suction (CS), is better. A meta-analysis of reported studies was conducted to compare the diagnostic yields of SP and CS during EUS-guided tissue acquisition. @*Methods@#We conducted a systematic electronic search using MEDLINE/PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials to identify clinical studies comparing SP and CS. We meta-analyzed accuracy, sensitivity, blood contamination and cellularity using the random-effects model. @*Results@#A total of 17 studies (seven randomized controlled trials, four prospective studies, and six retrospective studies) with 1,616 cases were included in the analysis. Compared to CS, there was a trend toward better accuracy (odds ratio [OR], 1.48; 95% confidence interval [CI], 0.97 to 2.27; p=0.07) and sensitivity (OR, 1.67; 95% CI, 0.95 to 2.93; p=0.08) with SP and a significantly lower rate of blood contamination (OR, 0.48; 95% CI, 0.33 to 0.69; p<0.01). However, there was no significant difference in cellularity between SP and CS, with an OR of 1.28 (95% CI, 0.68 to 2.40; p=0.45). When the use of a 25-gauge needle was analyzed, the accuracy and sensitivity of SP were significantly better than those of CS, with ORs of 4.81 (95% CI, 1.99 to 11.62; p<0.01) and 4.69 (95% CI, 1.93 to 11.40; p<0.01), respectively. @*Conclusions@#Compared to CS, SP appears to provide better accuracy and sensitivity in EUSguided tissue acquisition, especially when a 25-gauge needle is used.

A Meta-Analysis of Slow Pull versus Suction for Endoscopic Ultrasound-Guided Tissue Acquisition

Background/Aims@#Endoscopic ultrasound (EUS)-guided tissue acquisition is widely utilized as a diagnostic modality for intra-abdominal masses, but there remains debate regarding which suction technique, slow pull (SP) or conventional suction (CS), is better. A meta-analysis of reported studies was conducted to compare the diagnostic yields of SP and CS during EUS-guided tissue acquisition. @*Methods@#We conducted a systematic electronic search using MEDLINE/PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials to identify clinical studies comparing SP and CS. We meta-analyzed accuracy, sensitivity, blood contamination and cellularity using the random-effects model. @*Results@#A total of 17 studies (seven randomized controlled trials, four prospective studies, and six retrospective studies) with 1,616 cases were included in the analysis. Compared to CS, there was a trend toward better accuracy (odds ratio [OR], 1.48; 95% confidence interval [CI], 0.97 to 2.27; p=0.07) and sensitivity (OR, 1.67; 95% CI, 0.95 to 2.93; p=0.08) with SP and a significantly lower rate of blood contamination (OR, 0.48; 95% CI, 0.33 to 0.69; p<0.01). However, there was no significant difference in cellularity between SP and CS, with an OR of 1.28 (95% CI, 0.68 to 2.40; p=0.45). When the use of a 25-gauge needle was analyzed, the accuracy and sensitivity of SP were significantly better than those of CS, with ORs of 4.81 (95% CI, 1.99 to 11.62; p<0.01) and 4.69 (95% CI, 1.93 to 11.40; p<0.01), respectively. @*Conclusions@#Compared to CS, SP appears to provide better accuracy and sensitivity in EUSguided tissue acquisition, especially when a 25-gauge needle is used.

Endoscopic Ultrasound-Guided Tissue Acquisition by 22-Gauge Franseen and Standard Needles for Solid Pancreatic Lesions

Background/Aims@#Recently, a three-plane symmetric nee-dle with Franseen geometry was developed for endoscopic ultrasound-guided fine needle biopsy (EUS-FNB). In this ret-rospective study, tissue acquisition per pass was compared between 22-gauge Franseen FNB and standard fine needle aspiration (FNA) needles in patients with solid pancreatic le-sions. @*Methods@#Consecutive patients who underwent EUSFNA or EUS-FNB for solid pancreatic lesions between Octo-ber 2014 and March 2018 were retrospectively studied. The tissue acquisition rate and the diagnostic performance per session, per pass, and at first pass were compared. @*Results@#A total of 663 passes (300 by the FNB needle and 363 by the standard FNA needle) were performed in 154 patients (71 FNB and 83 FNA). The tissue acquisition rate per session and at first pass in the FNB and FNA groups was 100% and 95% (p=0.13) and 87% and 69% (p=0.007), respectively. The multivariate analysis revealed that among the patients, EUS-FNB (odds ratio, 3.07; p=0.01) was associated with a higher first-pass tissue acquisition rate. While the tissue ac-quisition rate reached a plateau after the 4th pass with FNA, it reached a plateau after the 2nd pass with FNB. Among the 129 malignant cases, the histological tissue acquisition rate per session was similar (100% and 94%), but the sensitivity by histology alone per session was higher for FNB than for FNA (93% and 73%, p<0.01). @*Conclusions@#The results of our retrospective analysis indicated that compared with a standard FNA needle, a 22-gauge Franseen FNB needle was associated with a higher first-pass tissue acquisition rate.

Management of Difficult Bile Duct Stones by Large Balloon, Cholangioscopy, Enteroscopy and Endosonography

Endoscopic management of bile duct stones is now the standard of care, but challenges remain with difficult bile duct stones. There are some known factors associated with technically difficult bile duct stones, such as large size and surgically altered anatomy. Endoscopic mechanical lithotripsy is now the standard technique used to remove large bile duct stones, but the efficacy of endoscopic papillary large balloon dilatation (EPLBD) and cholangioscopy with intraductal lithotripsy has been increasingly reported. In patients with surgically altered anatomy, biliary access before stone removal can be technically difficult. Endotherapy using two new endoscopes is now utilized in clinical practice: enteroscopy-assisted endoscopic retrograde cholangiopancreatography and endoscopic ultrasound-guided antegrade treatment. These new approaches can be combined with EPLBD and/or cholangioscopy to remove large bile duct stones from patients with surgically altered anatomy. Since various endoscopic procedures are now available, endoscopists should learn the indications, advantages and disadvantages of each technique for better management of bile duct stones.

A Novel Partially Covered Self-Expandable Metallic Stent with Proximal Flare in Patients with Malignant Gastric Outlet Obstruction

BACKGROUND/AIMS: Endoscopic placement of self-expandable metal stents (SEMSs) has emerged as a palliative treatment for malignant gastric outlet obstruction (GOO). Although covered SEMSs can prevent tumor ingrowth, frequent migration of covered SEMSs may offset their advantages in preventing tumor ingrowth. METHODS: We conducted this multicenter, single-arm, retrospective study at six tertiary referral centers to evaluate the safety and efficacy of a partially covered SEMS with an uncovered large-bore flare at the proximal end as an antimigration system in 41 patients with symptomatic malignant GOO. The primary outcome was clinical success, and the secondary outcomes were technical success, stent dysfunction, adverse events, and survival after stent placement. RESULTS: The technical and clinical success rates were 100% and 95%, respectively. Stent dysfunctions occurred in 17 patients (41%), including stent migration in nine (23%), tumor ingrowth in one (2%), and tumor overgrowth in four (10%). Two patients (5%) developed adverse events: one pancreatitis and one perforation. No procedure-related death was observed. CONCLUSIONS: A novel partially covered SEMS with a large-bore flare proximal end was safe and effective for malignant GOO but failed to prevent stent migration. Further research is warranted to develop a covered SEMS with an optimal antimigration system.

Total Cholesterol Level for Assessing Pancreatic Insufficiency Due to Chronic Pancreatitis

BACKGROUND/AIMS: To determine the nutritional markers important for assessing the degree of pancreatic insufficiency due to chronic pancreatitis in routine clinical practice. METHODS: A total of 137 patients with chronic pancreatitis were followed up for more than 1 year. They were divided into two groups: a pancreatic diabetes mellitus (DM) group, consisting of 47 patients undergoing medical treatment for DM of pancreatic origin, and a nonpancreatic DM group, consisting of 90 other patients (including 86 patients without DM). Serum albumin, prealbumin, total cholesterol, cholinesterase, magnesium, and hemoglobin were compared between the two groups. RESULTS: The total cholesterol was significantly lower in the pancreatic than the nonpancreatic DM group (164 mg/dL vs 183 mg/dL, respectively; p=0.0028). Cholinesterase was significantly lower in the former group (263 U/L vs 291 U/L, respectively; p=0.016). Among the 37 patients with nonalcoholic pancreatitis, there was no difference in the cholinesterase levels between the pancreatic and nonpancreatic (296 U/L vs 304 U/L, respectively; p=0.752) DM groups, although cholesterol levels remained lower in the former (165 mg/dL vs 187 mg/dL, respectively; p=0.052). CONCLUSIONS: Cholinesterase levels are possibly affected by concomitant alcoholic liver injury. The total cholesterol level should be considered when assessing pancreatic insufficiency due to chronic pancreatitis.