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.     

全覆膜金属支架与塑料支架在不可切除的远端胆道 恶性梗阻中的应用对比研究

目的探讨经内镜逆行胆胰管造影术（endoscopic retrograde cholangiopancreatography,ERCP）下胆道全覆膜金属支架及塑料支架置入治疗远端胆道恶性梗阻性黄疸的有效性及安全性。方法回顾性分析并总结2012年11月—2018年12月收治的52例接受ERCP下全覆膜金属支架（WallFlex）置入和40例胆道塑料支架置入治疗不可切除的恶性梗阻性黄疸患者的操作成功率、临床成功率、通畅时间、堵塞率、再干预次数、总费用等临床资料。结果ERCP 操作成功率两组均为100.0%（92/92）,金属支架组和塑料支架组临床成功率分别为94.2%（49/52）和75.0%（30/40）（χ2 =6.89,P<0.01）。两组生存时间比较,差异无统计学意义（6.5个月比7.2个月, χ2=0.25,P>0.05）。金属支架组中位通畅时间较塑料支架组明显延长（182.0 d 比 84.0 d,P<0.01）。两组胰腺炎（χ2 =0.2,P>0.05）及胆管炎发生率(χ2 =0.2,P>0.05）比较差异无统计学意义。金属支架组发生堵塞的概率要明显少于塑料支架组 [7.8%（4/51）比 25.0%（10/40）, χ2 =5.25,P<0.05],在再次干预次数方面,金属支架组要明显少于塑料支架组（0.06 次比 0.38次,t=2.91,P<0.01）。塑料支架组和金属支架组在总费用上比较差异无统计学意义（42 956.1元比 44 851.5元,t=1.84,P=0.07）。结论ERCP下全覆膜金属支架置入对于不可切除的远端胆道恶性梗阻患者是一种安全、有效、经济的治疗方法,在通畅时间及再次干预次数等方面要明显优于塑料支架。     

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 bladder fossa. Rate of complications such as migration, and in-stent 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 FCSEMS 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 choledochoduodenal 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.     

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.     

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 management of biliary complications after liver transplantation: An evidence-based review

Biliary tract diseases are the most common complications following liver transplantation (LT) and usually include biliary leaks, strictures, and stone disease. Compared to deceased donor liver transplantation in adults, living donor liver transplantation is plagued by a higher rate of biliary complications. These may be promoted by multiple risk factors related to recipient, graft, operative factors and post-operative course. Magnetic resonance cholangiopancreatography is the first-choice examination when a biliary complication is suspected following LT, in order to diagnose and to plan the optimal therapy; its limitations include a low sensitivity for the detection of biliary sludge. For treating anastomotic strictures, balloon dilatation complemented with the temporary placement of multiple simultaneous plastic stents has become the standard of care and results in stricture resolution with no relapse in > 90% of cases. Temporary placement of fully covered self-expanding metal stents (FCSEMSs) has not been demonstrated to be superior (except in a pilot randomized controlled trial that used a special design of FCSEMSs), mostly because of the high migration rate of current FCSEMSs models. The endoscopic approach of non-anastomotic strictures is technically more difficult than that of anastomotic strictures due to the intrahepatic and/or hilar location of strictures, and the results are less satisfactory. For treating biliary leaks, biliary sphincterotomy and transpapillary stenting is the standard approach and results in leak resolution in more than 85% of patients. Deep enteroscopy is a rapidly evolving technique that has allowed successful treatment of patients who were not previously amenable to endoscopic therapy. As a result, the percutaneous and surgical approaches are currently required in a minority of patients.     

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 effi cacy and cost-effectiveness     

Fully covered,retrievable self-expanding metal stents (Niti-S) in palliation of malignant dysphagia: Long-term results of a prospective study

Abstract

Background. In the palliative treatment of malignant dysphagia, fully covered, retrievable metal stents are not commonly used, mainly due to the high risk of migration. Therefore, we performed a prospective study to evaluate the clinical efficacy of a fully covered, retrievable self-expanding metal stent (Niti-S). Method. Between October 1998 and February 2009, 100 consecutive patients with malignant esophageal obstruction treated with the fully covered Niti-S stent (Niti-S, Taewoong Medical, Seoul, South Korea) were included. Data collected contained functional outcome, feasibility of endoscopic stent retrieval, recurrent dysphagia, complications, and survival. Result. At 4 weeks after stent placement, dysphagia significantly improved in all patients (p = 0.000). Recurrent dysphagia occurred in 19 of 100 patients treated with Niti-S stents (19%) mainly due to tumor overgrowth (7/100, 7%), stent migration (6/100, 6%), and food impaction (6/100, 6%). Endoscopic stent retrieval was successful in all the attempted 17 patients (17/100, 17%) – 7 overgrowth, 6 stent migration, 2 stent degradation, and 2 severe pain. Major complications were 2 hemorrhage, 2 severe pain, and 1 tracheal compression (5/100, 5%), and minor complications were 10 retrosternal pain and 7 symptomatic gastroesophageal reflux (17/100, 17%). After a median follow-up of 142 days, 97 patients had expired. There was no stent-related mortality or 30-day mortality. Conclusion. The fully covered, retrievable Niti-S stent has proved its effectiveness for palliation of malignant dysphagia and feasibility of endoscopic retrieval. We estimate its dog-bone shaped flanges at both ends and it being completely covered provide good resistance to migration and overgrowth.     

Fully versus partially covered self‐expandable metal stents in benign esophageal strictures

Self‐expandable plastic stents are currently recommended for refractory benign esophageal strictures but they show disappointing results in terms of migration and long‐term efficacy. We report here our experience in the management of benign esophageal strictures with partially covered (PCSEMS) and fully covered self‐expandable metal stents (FCSEMS). We performed a retrospective analysis of self‐expandable metal stent (SEMS) placements for benign esophageal strictures from 1998 to 2011 in Rouen University Hospital. Twenty‐two patients (15 men, 7 women) attempted 40 esophageal SEMS placements (17 PCSEMS, 23 FCSEMS) during this period. All technical complications were migrations. Migration was noted after 3/17 PCSEMS (17.6%) and 4/23 FCSEMS placement (17.4%, P = ns). Clinical complications occurred after 6/17 PCSEMS and 2/23 FCSEMS placements (35.3% vs. 8.7%, P = 0.053). PCSEMS caused two major complications (fistulae) whereas FCSEMS did not cause any major complication (11.7% vs. 0%). Mean dysphagia score was significantly lower after SEMS placement (1.68 vs. 3.08, P < 0.001) with similar results for PCSEMS and FCSEMS. Stent placement resulted in long‐term clinical success for 23.5% of PCSEMS and 34.7% of FCSEMS (P = 0.0505). FCSEMS provide satisfying clinical success rate with an acceptable complication rate and they could constitute a relevant therapeutic option in the management of benign esophageal strictures.     

Randomized trial in malignant biliary obstruction:Plastic vs partially covered metal stents

AIM:To compare efficacy and complications of par-tially covered self-expandable metal stent(pcSEMS)to plastic stent(PS)in patients treated for malignant,infrahilar biliary obstruction.METHODS:Multicenter prospective randomized clinical trial with treatment allocation to a pcWallstent(SEMS)or a 10 French PS.Palliative patients aged≥18,for infrahilar malignant biliary obstruction and a Karnofsky performance scale index>60%from 6 participating North American university centers.Primary endpoint was time to stent failure,with secondary outcomes of death,adverse events,Karnofsky performance score and short-form-36 scale administered on a three-monthly basis for up to 2 years.Survival analyses were performed for stent failure and death,with Cox proportional hazards regression models to determine significant predictive characteristics.RESULTS:Eighty-five patients were accrued over 37mo,42 were randomized to the SEMS group and 83patients were available for analyses.Time to stent failure was 385.3±52.5 d in the SEMS and 153.3±19.8 d in the PS group,P=0.006.Time to death did not differ between groups(192.3±23.4 d for SEMS vs211.5±28.0 d for PS,P=0.70).The only significant predictor was treatment allocation,relating to the time to stent failure(P=0.01).Amongst other measured outcomes,only cholangitis differed,being more common in the PS group(4.9%vs 24.5%,P=0.029).The small number of patients in follow-up limits longitudinal assessments of performance and quality of life.From an initially planned 120 patients,only 85 patients were recruited.CONCLUSION:Partially covered SEMS result in a longer duration till stent failure without increased complication rates,yet without accompanying measurable benefits in survival,performance,or quality of life.     

Partially covered self-expandable metal stents versus polyethylene stents for malignant biliary obstruction: A cost-effectiveness analysis

BACKGROUND/OBJECTIVE:

Partially covered self-expandable metal stents (SEMS) and polyethylene stents (PES) are both commonly used in the palliation of malignant biliary obstruction. Although SEMS are significantly more expensive, they are more efficacious than PES. Accordingly, a cost-effectiveness analysis was performed.

METHODS:

A cost-effectiveness analysis compared the approach of initial placement of PES versus SEMS for the study population. Patients with malignant biliary obstruction underwent an endoscopic retrograde cholangiopancreatography to insert the initial stent. If the insertion failed, a percutaneous transhepatic cholangiogram was performed. If stent occlusion occurred, a PES was inserted at repeat endoscopic retrograde cholangiopancreatography, either in an outpatient setting or after admission to hospital if cholangitis was present. A third-party payer perspective was adopted. Effectiveness was expressed as the likelihood of no occlusion over the one-year adopted time horizon. Probabilities were based on a contemporary randomized clinical trial, and costs were issued from national references. Deterministic and probabilistic sensitivity analyses were performed.

RESULTS:

A PES-first strategy was both more expensive and less efficacious than an SEMS-first approach. The mean per-patient costs were US$6,701 for initial SEMS and US$20,671 for initial PES, which were associated with effectiveness probabilities of 65.6% and 13.9%, respectively. Sensitivity analyses confirmed the robustness of these results.

CONCLUSION:

At the time of initial endoscopic drainage for patients with malignant biliary obstruction undergoing palliative stenting, an initial SEMS insertion approach was both more effective and less costly than a PES-first strategy.     

Comparison of clinical outcomes of multiple plastic stents and covered metal stent in refractory pancreatic ductal strictures in chronic pancreatitis- a systematic review and meta-analysis

BackgroundSymptomatic pancreatic duct (PD) strictures in chronic pancreatitis refractory to single plastic stenting are usually managed by placement of multiple plastic stents (MPS). Fully covered self-expanding metallic stents (FCSEMS) have also been used in the management of these patients. However, the overall efficacy and safety of different types of stents is unclear from the currently available studies. We performed this meta-analysis to assess the efficacy and complications from MPS and FCSEMS in patients with PD strictures refractory to treatment with single plastic stents.MethodsSeveral electronic databases were searched for all the studies evaluating the outcome of placement of multiple plastic stents and fully covered metal stents in patients with PD strictures refractory to single plastic stenting. We calculated the Weighted Pooled Ratio (WPR) with Confidence Interval (CI) between the MPS and FCSEMS.ResultsA total of 13 studies (including 2 abstracts) were included in the analysis. MPS were placed in 106 patients and FCSEMS in 192 patients. Improvement in pain after stenting (P = 0.794), risk of recurrence of pain after removal of stent (P = 0.48) and stricture recurrence after stent removal (P = 0.52) were comparable between MPS and FCSEMS. Risk of endoscopic re-intervention was also comparable between metal stents and MPS. However, FCSEMS was associated with overall higher risk of adverse events (P < 0.0001).ConclusionFCSEMS are comparable to multiple plastic stents in the treatment of symptomatic refractory PD strictures. However, use of FCSEMS is associated with increased risk of adverse events.