Angle of covered self-expandable metallic stents after placement is a risk factor for recurrent biliary obstruction

BACKGROUND Studies have shown that covered self-expandable metallic stents(CSEMS)with a low axial forces after placement can cause early recurrent biliary obstruction(RBO)due to precipitating sludge formation.AIM To ascertain whether the angle of CSEMS after placement is a risk factor for RBO in unresectable distal malignant biliary obstruction(MBO).METHODS Between January 2010 and March 2019,261 consecutive patients underwent selfexpandable metallic stent insertion by endoscopic retrograde cholangiopancreatography at our facility,and 87 patients were included in this study.We evaluated the risk factors for RBO,including the angle of CSEMS after placement as the primary outcome.We measured the obtuse angle of CSEMS after placement on an abdominal radiograph using the SYNAPSE PACS system.We also evaluated technical and functional success,adverse events,time to RBO(TRBO),non-RBO rate,survival time,cause of RBO,and reintervention procedure as secondary outcomes.RESULTS We divided the patients into two cohorts based on the presence or absence of RBO.The angle of CSEMS after placement(per 1°and per 10°)was evaluated using the multivariate Cox proportional hazard analysis,which was an independent risk factor for RBO in unresectable distal MBO[hazard ratio,0.97 and 0.71;95%confidence interval(CI):0.94-0.99 and 0.54-0.92;P=0.01 and 0.01,respectively].For early diagnosis of RBO,the cut-off value of the angle of CSEMS after placement using the receiver operating characteristic curve was 130°[sensitivity,50.0%;specificity 85.5%;area under the curve 0.70(95%CI:0.57-0.84)].TRBO in the<130°angle group was significantly shorter than that in the≥130°angle group(P<0.01).CONCLUSION This study suggests that the angle of the CSEMS after placement for unresectable distal MBO is a risk factor for RBO.These novel results provide pertinent information for future stent management.

Endoscopic ultrasound-guided choledochoduodenostomies with fully covered self-expandable metallic stents

AIM:To investigate the long-term outcomes of endoscopic ultrasound-guided choledochoduodenostomy(EUS-CDS) with a fully covered self-expandable metallic stent(FCSEMS).METHODS:From April 2009 to August 2010,15 patients with distal malignant biliary obstructions who were candidates for alternative techniques for biliary decompression due to a failed endoscopic retrograde cholangiopancreatography(ERCP) were included.These 15 patients consisted of 8 men and 7 women and had a median age of 61 years(range:30-91 years).The underlying causes of the distal malignant biliary obstruction were pancreatic cancer(n = 9),ampulla of Vater cancer(n = 2),renal cell carcinoma(n = 1),advanced gastric cancer(n = 1),lymphoma(n = 1),and duodenal cancer(n = 1).RESULTS:The technical success rate of EUS-CDS with an FCSEMS was 86.7%(13/15),and functional success was achieved in 100%(13/13) of those cases.In two patients,the EUS-CDS failed because an FCSEMS with a delivery device could not be passed into the common bile duct.The mean duration of stent patency was 264 d.Early adverse events developed in three patients(3/13,23.1%),including self-limited pneumoperitoneum in two patients and cholangitis requiring stent reposition in one patient.During the follow-up period(median:186 d,range:52-388 d),distal stent migration occurred in four patients(4/13,30.8%).In 3 patients,the FCSEMS could be reinserted through the existing choledochoduodenal fistula tract.CONCLUSION:EUS-CDS with an FCSEMS is technically feasible and can lead to effective palliation of distal malignant biliary obstructions after failed ERCP.

Chronic pancreatic pain successfully treated by endoscopic ultrasound-guided pancreaticogastrostomy using fully covered self-expandable metallic stent

One of the most common symptoms presenting in patients with chronic pancreatitis is pancreatic-type pain.Obstruction of the main pancreatic duct in chronic pancreatitis can be treated by a multitude of therapeutic approaches,ranging from pharmacologic,endoscopic and radiologic treatments to surgical interventions.When the conservative treatment approaches fail to resolve symptomatic cases,however,endoscopic retrograde pancreatography with pancreatic duct drainage is the preferred second approach,despite its well-recognized drawbacks.When the conventional transpapillary approach fails to achieve the necessary drainage,the patients may benefit from application of the less invasive endoscopic ultrasound(EUS)-guided pancreatic duct interventions.Here,we describe the case of a 42-year-old man who presented with severe abdominal pain that had lasted for 3 mo.Computed tomography scanning showed evidence of chronic obstructive pancreatitis with pancreatic duct stricture at genu.After conventional endoscopic retrograde pancreaticography failed to eliminate the symptoms,EUS-guided pancreaticogastrostomy(PGS)was applied using a fully covered,self-expandable,10-mm diameter metallic stent.The treatment resolved the case and the patient experienced no adverse events.EUS-guided PGS with a regular biliary fully covered,self-expandable metallic stent effectively and safely treated pancreatictype pain in chronic pancreatitis.

Efficacy of uncovered self-expandable metallic stent for colorectal obstruction by extracolonic malignancy

BACKGROUND Self-expandable metallic stent(SEMS)is widely used for malignant colorectal obstruction.Recently,SEMS has been used for palliative option for colorectal obstruction caused by extracolonic malignancy(ECM).AIM To evaluate the efficacy of SEMS for colorectal obstruction caused by ECM,and to identify the factors associated with stent occlusion.METHODS Seventy-two patients who were treated with uncovered SEMS insertion for malignant colorectal obstructions caused by colorectal metastasis or peritoneal seeding of ECM at Samsung Medical Center between April 2012 to March 2016 were enrolled.We analyzed technical and clinical outcomes of stent insertion,the factors associated with stent occlusion and long term outcomes after stent insertion.RESULTS Technical success rate was determined as 90.3%with a clinical success rate of 87.7%.Stent occlusion developed in 28.1%,with a median duration of 51 d.Further,81.3%with stent occlusion could be treated with secondary stent insertion.Clinical failure was observed to be related to the male sex(P=0.020)and right colon obstruction(P=0.017).Stent length≤10 cm was found to be associated with stent occlusion(P=0.003).Median survival time after stent insertion was 4.7 mo and 40.4%were able to receive their oncological treatments after stent insertion without surgery.CONCLUSION Uncovered SEMS is effective for the treatment of colorectal obstruction caused by ECM,considering life expectancy of patients with ECM.

Case of arterial hemorrhage after endoscopic papillary large balloon dilation for choledocholithiases using a covered self-expandable metallic stent

A 78-year-old male was admitted to our hospital because of choledocholithiasis.ERC demonstrated choledocholithiases with a maximum diameter of 13 mm, and we performed endoscopic papillary large balloon dilation(EPLBD) with a size of 15 mm.Immediately following the balloon deflation, spurting hemorrhage occurred from the orifice of the duodenal papilla.Although we performed endoscopic hemostasis by compressing the bleeding point with the large balloon catheter, we could not achieve hemostasis.Therefore, we placed a 10 mm fully covered selfexpandable metallic stent(SEMS) across the duodenal papilla, and the hemorrhage stopped immediately.After 1 wk of SEMS placement, duodenal endoscopy revealed ulcerative lesions in both the orifice of the duodenal papilla and the lower bile duct.A direct peroral cholangioscopy using an ultra-slim upper endoscope revealed a visible vessel with a longitudinal mucosal tear in the ulceration of the lower bile duct.We believe that the mucosal tear and subsequent ruptured vessel were caused by the EPLBD procedure.

Fully covered self-expandable metal stents for treatment of malignant and benign biliary strictures

AIM:To present a series of covered self-expandable metal stents(CSEMS) placed for different indications and to evaluate the effectiveness,complications and extractability of these devices.METHODS:We therefore retrospectively reviewed the courses of patients who received CSEMS due to malignant as well as benign biliary strictures and postsphincterotomy bleeding in our endoscopic unit between January 2010 and October 2011.RESULTS:Twenty-six patients received 28 stents due to different indications(20 stents due to malignant biliary strictures,six stents due to benign biliary strictures and two stents due to post-sphincterotomy bleeding).Biliary obstruction was relieved in all cases,regardless of the underlying cause.Hemostasis could be achieved in the two patients who received the stents for this purpose.Complications occurred in five patients(18%).Two patients(7%) developed cholecystitis,stents dislocated/migrated in other two patients(7%),and in one patient(3.6%) stent occlusion was documented during the study period.Seven stents were extracted endoscopically.Removal of stents was easily possible in all cases in which it was desired using standard forceps.Twelve patients underwent surgery with pylorus preserving duodenopancreatectomy.In all patients stents could be removed during the operation without difficulties.CONCLUSION:Despite the higher costs of these devices,fully covered self-expanding metal stents may be suitable to relief biliary obstruction due to bile duct stenosis,regardless of the underlying cause.CSEMS may also represent an effective treatment strategy of severe post-sphincterotomy bleeding,not controlled by other measures.

Placement of a fully covered self-expandable metal stent in a young patient with chronic pancreatitis

Plastic stent insertion is a treatment option for pancreatic duct stricture with chronic pancreatitis.However, recurrent stricture is a limitation after removing the plastic stent.Self-expandable metal stents have long diameters and patency.A metal stent has become an established management option for pancreatic duct stricture caused by malignancy but its use in benign stricture is still controversial.We introduce a young patient who had chronic pancreatitis and underwent several plastic stent insertions due to recurrent pancreatic duct stricture.His symptoms improved after using a fully covered self-expandable metal covered stent and there was no recurrence found at follow-up at the outpatient department.

Safety and efficacy of a partially covered self-expandable metal stent in benign pyloric obstruction

AIM:To evaluate the safety and efficacy of partially covered self-expandable metallic stents(SEMSs)in benign pyloric obstruction.METHODS:We retrospectively analyzed data from 10consecutive patients with peptic ulcer-related pyloric obstructive symptoms(gastric outlet obstruction scoring system(GOOSS)score of 1)between March 2012and September 2013.The patients were referred to and managed by partially covered SEMS insertion in our tertiary academic center.We assessed the technical success,symptom improvement,and adverse events after stenting.RESULTS:Early symptoms were improved just 3 d after SEMS placement in all 10 patients.The GOOSS score of all patients improved from 1 to 3.There were no serious immediate adverse events.The overall rate of being symptom free was 90%at a median of 11mo of follow-up(range:4-43 mo).Five patients were managed by a rescue SEMS because of failure of previous endoscopic balloon dilatation.Among them,four patients had sustained symptom improvement after the SEMS procedure.During the follow-up period,migration of the SEMS was observed in two patients(20.0%),both of whom had previous endoscopic balloon dilatation before SEMS insertion.CONCLUSION:Despite the small number in this study,partially covered SEMSs showed a favorable and safe outcome in the treatment of na?ve benign pyloric obstruction and in salvage treatment after balloon dilatation failure.

Evaluation of anti-migration properties of biliary covered self-expandable metal stents

AIM: To assess anti-migration potential of six biliary covered self-expandable metal stents(C-SEMSs) by using a newly designed phantom model. METHODS: In the phantom model, the stent was placed in differently sized holes in a silicone wall and retracted with a retraction robot. Resistance force to migration(RFM) was measured by a force gauge on the stent end. Radial force(RF) was measured with a RF measurement machine. Measured flare structure variables were the outer diameter, height, and taper angle of the flare(ODF, HF, and TAF, respectively). Correlations between RFM and RF or flare variables were analyzed using a linear correlated model.RESULTS: Out of the six stents, five stents were braided, the other was laser-cut. The RF and RFM of each stent were expressed as the average of five replicate measurements. For all six stents, RFM and RF decreased as the hole diameter increased. For all six stents, RFM and RF correlated strongly when the stent had not fully expanded. This correlation was not observed in the five braided stents excluding the laser cut stent. For all six stents, there was a strong correlation between RFM and TAF when the stent fully expanded. For the five braided stents, RFM after full stent expansion correlated strongly with all three stent flare structure variables(ODF, HF, and TAF). The laser-cut C-SEMS had higher RFMs than the braided C-SEMSs regardless of expansion state.CONCLUSION: RF was an important anti-migration property when the C-SEMS did not fully expand. Once fully expanded, stent flare structure variables plays an important role in anti-migration.

Endoscopic transpapillary gallbladder drainage with replacement of a covered self-expandable metal stent

Endoscopic self-expandable metal stent (SEMS) placement has become a standard palliative therapy for pa- tients with malignant biliary obstruction. Acute cholecystitis after SEMS placement is a serious complication. We report a patient with an acute cholecystitis after covered SEMS placement, who was managed successfully with endoscopic transpapillary gallbladder drainage (ETGBD) and replacement of the covered SEMS. An 85-year-old man with pancreatic cancer suffered from acute cholecystitis after covered SEMS placement. It was impossible to perform percutaneous transhepatic gallbladder drainage. After removal of the covered SEMS with a snare, a 7Fr double pigtail stent was placed between the gallbladder and duodenum, subsequently followed by another covered SEMS insertion into the common bile duct beside the gallbladder stent. The cholecystitis improved immediately after ETGBD. ETGBD with replacement of the covered SEMS thus proved to be effective for treatment of patients with acute cholecystitis after covered SEMS placement.

Drug-eluting fully covered self-expanding metal stent for dissolution of bile duct stones in vitro

BACKGROUND The treatment of difficult common bile duct stones(CBDS)remains a big challenge around the world.Biliary stenting is a widely accepted rescue method in patients with failed stone extraction under endoscopic retrograde cholangiopancreatography.Fully covered self-expanding metal stent(FCSEMS)has gained increasing attention in the management of difficult CBDS.AIM To manufacture a drug-eluting FCSEMS,which can achieve controlled release of stone-dissolving agents and speed up the dissolution of CBDS.METHODS Customized covered nitinol stents were adopted.Sodium cholate(SC)and disodium ethylene diamine tetraacetic acid(EDTA disodium,EDTA for short)were used as stone-dissolving agents.Three different types of drug-eluting stents were manufactured by dip coating(Stent I),coaxial electrospinning(Stent II),and dip coating combined with electrospinning(Stent III),respectively.The drugrelease behavior and stone-dissolving efficacy of these stents were evaluated in vitro to sort out the best manufacturing method.And the selected stonedissolving stents were further put into porcine CBD to evaluate their biosecurity.RESULTS Stent I and Stent II had obvious burst release of drugs in the first 5 d while Stent III presented controlled and sustainable drug release for 30 d.In still buffer,the final stone mass-loss rate of each group was 5.19%±0.69%for naked FCSEMS,20.37%±2.13%for Stent I,24.57%±1.45%for Stent II,and 33.72%±0.67%for Stent III.In flowing bile,the final stone mass-loss rate of each group was 5.87%±0.25%for naked FCSEMS,6.36%±0.48%for Stent I,6.38%±0.37%for Stent II,and 8.15%±0.27%for Stent III.Stent III caused the most stone mass-loss no matter in still buffer or in flowing bile,which was significantly higher than those of other groups(P<0.05).In vivo,Stent III made no difference from naked FCSEMS in serological analysis(P>0.05)and histopathological examination(P>0.05).CONCLUSION The novel SC and EDTA-eluting FCSEMS is efficient in diminishing CBDS in vitro.When conventional endoscopic techniques fail to remove difficult CBDS,SC and EDTA-eluting FCSEMS implantation may be considered a promising alternative.

Self-expandable metallic stent placement plus laparoscopy for acute malignant colorectal obstruction

AIM:To investigate the clinical advantages of the stent-laparoscopy approach to treat colorectal cancer(CRC)patients with acute colorectal obstruction(ACO).METHODS:From April 2008 to April 2012,surgeryrelated parameters,complications,overall survival(OS),and disease-free survival(DFS)of 74 consecutive patients with left-sided CRC presented with ACO who underwent self-expandable metallic stent(SEMS)placement followed by one-stage open(n=58)or laparoscopic resection(n=16)were evaluated retrospectively.The stent-laparoscopy group was also compared with a control group of 96 CRC patients who underwent regular laparoscopy without ACO between January 2010 and December 2011 to explore whether SEMS placement influenced the laparoscopic procedure or reduced long-term survival by influencing CRC oncological characteristics.RESULTS:The characteristics of patients among these groups were comparable.The rate of conversion to open surgery was 12.5%in the stent-laparoscopy group.Bowel function recovery and postoperative hospital stay were significantly shorter(3.3±0.9 d vs 4.2±1.5 d and 6.7±1.1 d vs 9.5±6.7 d,P=0.016 and P=0.005),and surgical time was significantly longer(152.1±44.4 min vs 127.4±38.4 min,P=0.045)in the stent-laparoscopy group than in the stent-open group.Surgery-related complications and the rate of admission to the intensive care unit were lower in the stent-laparoscopy group.There were no significant differences in the interval between stenting and surgery,intraoperative blood loss,OS,and DFS between the two stent groups.Compared with those in the stentlaparoscopy group,all surgery-related parameters,complications,OS,and DFS in the control group were comparable.CONCLUSION:The stent-laparoscopy approach is a feasible,rapid,and minimally invasive option for patients with ACO caused by left-sided CRC and can achieve a favorable long-term prognosis.

Use of fully covered self-expanding metal stents in benign biliary diseases

Biliary fully covered self-expanding metal stents (FCSEMS) are now being used to treat several benign biliary conditions. Advantages include small predeployment and large postexpansion diameters in addition to an easy insertion technique. Lack of imbedding of the metal into the bile duct wall enables removability. In benign biliary strictures that usually require multiple procedures, despite the substantially higher cost of FCSEMS compared with plastic stents, the use of FCSEMS is offset by the reduced number of endoscopic retrograde cholangiopancreatography interventions required to achieve stricture resolution. In the same way, FCSEMS have also been employed to treat complex bile leaks, perforation and bleeding after endoscopic biliary sphincterotomy and as an aid to maintain permanent drainage tracts obtained by means of Endoscopic Ultrasound-guided biliary drainage. Good success rates have been achieved in all these conditions with an acceptable number of complications. FCSEMS were successfully removed in all patients. Comparative studies of FCSEMS and plastic stents are needed to demonstrate efficacy and cost-effectiveness

Evaluation of fully covered self-expanding metal stents in benign biliary strictures and bile leaks

AIM: To investigate the use of fully covered metal stents in benign biliary strictures (BBS) and bile leaks. METHODS: We studied 17 patients, at Harbor-UCLA Medical center (Los Angeles), with BBS (n=12) and bile leaks (n=5) from July 2007 to February 2012 that had received placement of fully covered self-expanding metal stents (FCSEMs). Fourteen patients had endoscopic placement of VIABIL (Conmed, Utica, New York, United States) stents and three had Wallflex (Boston Scientific, Mass) stents. FCSEMS were 8 mm or 10 mm in diameter and 4 cm to 10 cm in length. Patients were followed at regular intervals to evaluate for symptoms and liver function tests. FCSEMS were removed after 4 or more weeks. Resolution of BBS and leak was documented cholangiographically following stent removal. Stent patency can be defined as adequate bile and contrast flow from the stent and into the ampulla during endoscopic retrograde cholangiopancreatography (ERCP) without clinical signs and/or symptoms of biliary obstruction. Criterion for bile leak resolution at ERCP is defined as absence of contrast extravasation from the common bile duct, cystic duct remanent, or gall blad-der fossa. Rate of complications such as migration, and instent occlusion were recorded. Failure of endoscopic therapy was defined as persistent biliary stenosis or continuous biliary leakage after 12 mo of stent placement. RESULTS: All 17 patients underwent successful FC- SEMS placement and removal. Etiologies of BBS included: cholecystectomies (n=8), cholelithiasis (n=2), hepatic artery compression (n=1), pancreatitis (n=2), and Whipple procedure (n=1). All bile leaks occurred following cholecystectomy. The anatomic location of BBS varied: distal common bile duct (n=7), common hepatic duct (n=1), hepaticojejunal anastomosis (n=2), right intrahepatic duct (n=1), and choledochoduo-denal anastomatic junction (n=1). All bile leaks were found to be at the cystic duct. Twelve of 17 patients had failed prior stent placement or exchange. Resolution of the biliary strictures and bile leaks was achieved in 16 of 17 patients (94%). The overall median stent time was 63 d (range 27-251 d). The median stent time for the BBS group and bile leak group was 62 ± 58 d (range 27-199 d) and 92 ± 81 d (range 48-251 d), respectively. All 17 patients underwent successful FCSEMS removal. Long term follow-up was obtained for a median of 575 d (range 28-1435 d). Complications occurred in 5 of 17 patients (29%) and included: migration (n=2), stent clogging (n=1), cholangitis (n=1), and sepsis with hepatic abscess (n=1). CONCLUSION: Placement of fully covered self-expanding metal stents may be used in the management of benign biliary strictures and bile leaks with a low rate of complications.

Self-expandable metallic stents for palliation of patients with malignant gastric outlet obstruction caused by stomach cancer

AIM: To ascertain clinical outcome and complications of self-expandable metal stents for endoscopic palliation of patients with malignant obstruction of the gastrointestinal (GI) tract. METHODS: A retrospective review was performed throughout August 2000 to June 2005 of 53 patients with gastric outlet obstruction caused by stomach cancer. All patients had symptomatic obstruction including nausea, vomiting, and decreased oral intake. All received self-expandable metallic stents. RESULTS: Stent implantation was successful in all 53 (100%) patients. Relief of obstructive symptoms was achieved in 43 (81.1%) patients. No immediate stent-related complications were noted. Seventeen patients had recurrent obstruction (tumor ingrowth in 14 patients, tumor overgrowth in 1 patient, and partial distal stent migration in 2 patients). The mean survival was 145 d. Median stent patency time was 187 d. CONCLUSION: Endoscopic placement of self-expandable metallic stents is a safe and effective treatment for the palliation of patients with inoperable malignant gastric outlet obstruction caused by stomach cancer.

Predictive factors for the failure of endoscopic stent-instent self-expandable metallic stent placement to treat malignant hilar biliary obstruction

AIM To investigate the factors predictive of failure when placing a second biliary self-expandable metallic stents(SEMSs). METHODS This study evaluated 65 patients with an unresectable malignant hilar biliary obstruction who were examined in our hospital. Sixty-two of these patients were recruited to the study and divided into two groups: the success group, which consisted of patients in whom a stent-in-stent SEMS had been placed successfully, and the failure group, which consisted of patients in whom the stent-in-stent SEMS had not been placed successfully. We compared the characteristics of the patients, the stricture state of their biliary ducts, and the implemented endoscopic retrograde cholangiopancreatography(ERCP) procedures between the two groups.RESULTS The angle between the target biliary duct stricture and the first implanted SEMS was significantly larger in the failure group than in the success group. There were significantly fewer wire or dilation devices(ERCP catheter, dilator, or balloon catheter) passing the first SEMS cell in the failure group than in the success group. The cut-off value of the angle predicting stent-in-stent SEMS placement failure was 49.7 degrees according to the ROC curve(sensitivity 91.7%, specificity 61.2%). Furthermore, the angle was significantly smaller in patients with wire or dilation devices passing the first SEMS cell than in patients without wire or dilation devices passing the first SEMS cell. CONCLUSION A large angle was identified as a predictive factor for failure of stent-in-stent SEMS placement.

Safety and efficacy of self-expandable metallic stents in malignant small bowel obstructions

In this report, we present 3 cases of malignant small bowel obstruction, treated with palliative care using endoscopic self-expandable metallic stent(SEMS) placement, with the aim to identify the safety and efficacy of this procedure. Baseline patient characteristics, procedure methods, procedure time, technical and clinical success rates, complications, and patient outcomes were obtained. All 3 patients had pancreatic cancer with small bowel strictures. One patient received the SEMS using colonoscopy, while the other 2 patients received SEMS placement via double balloon endoscopy using the through-the-overtube technique. The median procedure time was 104 min. The technical and clinical success rates were 100%. Post-treatment, obstructive symptoms in all patients improved, and a low-residue diet could be tolerated. All stents remained within the patients until their deaths. The median overall survival time(stent patency time) was 76 d. SEMS placement is safe and effective as a palliative treatment for malignant small bowel obstruction.

Management of post-gastrectomy anastomosis site obstruction with a self-expandable metallic stent

Post-gastrectomy anastomosis site obstruction is a relatively rare complication after a subtotal gastrectomy.We present a case of a 75-year-old man who underwent a truncal vagotomy, omental patch, gastrojejunostomy, and Braun anastomosis for duodenal ulcer perforation and a gastric outlet obstruction.Following the 10 th postoperative day, the patient complained of abdominal discomfort and vomiting.We diagnosed post-gastrectomy anastomosis site obstruction by an upper gastrointestinal series and an upper endoscopic examination.We inserted a self-expandable metallic stent(SEMS) at the anastomosis site.The stent was fully expanded after deployment.On the day following the stent insertion, the patient began to eat, and his abdominal discomfort was resolved.This paper describes the successful management of post-gastrectomy anastomosis site obstruction with temporary placement of a SEMS.

Endoscopic removal and trimming of distal self-expandable metallic biliary stents

AIM:To evaluate the efficacy and safety of endoscopic removal and trimming of self-expandable metallic stents(SEMS).METHODS:All SEMS had been placed for distal biliary strictures.Twenty-seven endoscopic procedures were performed in 19 patients in whom SEMS(one uncovered and 18 covered) removal had been attempted,and 8 patients in whom stent trimming using argon plasma coagulation(APC) had been attempted at Tokyo Medical University Hospital.The APC settings were:voltage 60-80 W and gas flow at 1.5 L/min.RESULTS:The mean stent indwelling period for all patients in whom stent removal had been attempted was 113.7 ± 77.6 d(range,8-280 d).Of the 19 patients in whom removal of the SEMS had been attempted,the procedure was successful in 14(73.7%) without procedure-related adverse events.The indwelling period in the stent removable group was shorter than that in the unremovable group(94.9 ± 71.5 d vs 166.2 ± 76.2 d,P = 0.08).Stent trimming was successful for all patients with one minor adverse event consisting of self-limited hemorrhage.Trimming time ranged from 11 to 16 min.CONCLUSION:Although further investigations on larger numbers of cases are necessary to accumulate evidence,the present data suggested that stent removal and stent trimming is feasible and effective for stent-related complications.

Revision of bilateral self-expandable metallic stents placed using the stent-in-stent technique for malignant hilar biliary obstruction

Background: Endoscopic biliary decompression using bilateral self-expandable metallic stent(SEMS) placed using the stent-in-stent(SIS) technique is considered favorable for unresectable malignant hilar biliary obstruction(MHBO). However, occlusion of the bilateral SIS placement is frequent and revision can be challenging. This study was performed to investigate the efficacy, the long-term patency and the appropriate approach for revision of occluded bilateral SIS placement in unresectable MHBO. Methods: From January 2011 to July 2016, thirty-eight patients with unresectable MHBO underwent revision of occluded bilateral SIS placement. Clinical data including success rates and patency of revision, were retrospectively analyzed. Results: The technical success rate of revision was 76.3%. The clinical success rate of revision was 51.7% and mean patency of revision was 49.1 days. No significant predictive factor for clinical failure of revision was observed. The cell size of SEMS was not found to have significant effects on clinical success rates or revision patency. Conclusions: Revision of occluded bilateral SIS placement for MHBO showed fair patency and clinical success rate. Revision method and cell size of SEMS were not found to influence clinical outcomes.