Outcomes of colon self-expandable metal stents for malignant vs benign indications at a tertiary care center and review of literature

BACKGROUND Endoscopic placement of a self-expandable metal stent(SEMS)is a minimally invasive treatment for use in malignant and benign colonic obstruction.However,their widespread use is still limited with a nationwide analysis showing only 5.4%of patients with colon obstruction undergoing stent placement.This underutilization could be due to perceived increase risk of complications with stent placement.AIM To review long-and short-term clinical success of SEMS use for colonic obstruction at our center.METHODS We retrospectively reviewed all the patients who underwent colonic SEMS placement over aeighteen year period (August 2004 through August 2022) at our academic center. Demographicsincluding age, gender, indication (malignant and benign), technical success, clinical success,complications (perforation, stent migration), mortality, and outcomes were recorded.RESULTSSixty three patients underwent colon SEMS over an 18-year period. Fifty-five cases were formalignant indications, 8 were for benign conditions. The benign strictures included diverticulardisease stricturing (n = 4), fistula closure (n = 2), extrinsic fibroid compression (n = 1), and ischemicstricture (n = 1). Forty-three of the malignant cases were due to intrinsic obstruction from primaryor recurrent colon cancer;12 were from extrinsic compression. Fifty-four strictures occurred on theleft side, 3 occurred on the right and the rest in transverse colon. The total malignant case (n = 55)procedural success rate was 95% vs 100% for benign cases (P = 1.0, NS). Overall complication ratewas significantly higher for benign group: Four complications were observed in the malignantgroup (stent migration, restenosis) vs 2 of 8 (25%) for benign obstruction (1-perforation, 1-stentmigration) (P = 0.02). When stratifying complications of perforation and stent migration there wasno significant difference between the two groups (P = 0.14, NS).CONCLUSIONColon SEMS remains a worthwhile option for colonic obstruction related to malignancy and has ahigh procedural and clinical success rate. Benign indications for SEMS placement appear to havesimilar success to malignant. While there appears to be a higher overall complication rate inbenign cases, our study is limited by sample size. When evaluating for perforation alone theredoes not appear to be any significant difference between the two groups. SEMS placement may bea practical option for indications other that malignant obstruction. Interventional endoscopistsshould be aware and discuss the risk for complications in setting of benign conditions. Indicationsin these cases should be discussed in a multi-disciplinary fashion with colorectal surgery.

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.

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.

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.

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.

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.

Self-expanding metallic stents drainage for acute proximal colon obstruction

AIM: To clarify the usefulness of the self-expanding metallic stents (SEMS) in the management of acute proximal colon obstruction due to colon carcinoma before curative surgery.METHODS: Eighty-one colon (proximal to spleen flex) carcinoma patients (47 males and 34 females,aged 18-94 years,mean = 66.2 years) treated between September 2004 and June 2010 for acute colon obstruction were enrolled to this study,and their clinical and radiological features were reviewed.After a cleaning enema was administered,urgent colonoscopy was performed.Subsequently,endoscopic decompression using SEMS placement was attempted.RESULTS: Endoscopic decompression using SEMS placement was technically successful in 78 (96.3%) of 81 patients.Three patients’ symptoms could not be relieved after SEMS placement and emergent operation was performed 1 d later.The site of obstruction was transverse colon in 18 patients,the hepatic flex in 42,and the ascending colon in 21.Following adequate cleansing of the colon,patients’ abdominal girth was decreased from 88 ± 3 cm before drainage to 72 ± 6 cm 7 d later,and one-stage surgery after 8 ± 1 d (range,7-10 d) was performed.No anastomotic leakage or postoperative stenosis occurred after operation.CONCLUSION: SEMS placement is effective and safe in the management of acute proximal colon obstruction due to colon carcinoma,and is considered as a bridged method before curative surgery.

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.

Temporary self-expanding metallic stents for achalasia: A prospective study with a long-term follow-up

AIM: To compare the efficacy of self-expanding metallic stents (SEMSs) for the long-term clinical treatment of achalasia. METHODS: Ninety achalasic patients were treated with a temporary SEMS with a diameter of 20 mm (n = 30, group A), 25 mm (n = 30, group B) or 30 mm (n = 30, group C). Data on clinical symptoms, complications and treatment outcomes were collected, and follow-up was made at 6 mo and at 1, 3-5, 5-8, 8-10 and > 10 years, postoperatively.RESULTS: Stent placement was successful in all patients. Although chest pain occurrence was high, stent migration was less in group C than in groups A and B. The clinical remission rate at 5-8, 8-10 and > 10 years in group C was higher than that in the other two groups. The treatment failure rate was lower in group C (13%) than in groups A (53%) and B (27%). SEMSs in group C resulted in reduced dysphagia scores and lowered esophageal sphincter pressures, as well as normal levels of barium height and width during all the follow-up time periods. Conversely, these parameters increased over time in groups A and B. The primary patency in group C was longer than in groups A and B. CONCLUSION: A temporary SEMS with a diameter of 30 mm is associated with a superior long-term clinical efficacy in the treatment of achalasia compared with a SEMS with a diameter of 20 mm or 25 mm.

Treatment of malignant gastric outlet obstruction with endoscopically placed self-expandable metal stents

Malignant gastroduodenal obstruction can occur in up to 20%of patients with primary pancreatic,gastric or duodenal carcinomas.Presenting symptoms include nausea,vomiting,abdominal distention,pain and decreased oral intake which can lead to dehydration, malnutrition,and poor quality of life.Endoscopic stent placement has become the primary therapeutic modality because it is safe,minimally invasive,and a cost-effective option for palliation.Stents can be successfully deployed in the majority of patients. Stent placement appears to lead to a shorter time to symptomatic improvement,shorter time to resumption of an oral diet,and shorter hospital stays as compared with surgical options.Recurrence of the obstructive symptoms resulting from stent occlusion,due to tumor ingrowth or overgrowth,can be successfully treated with repeat endoscopic stent placement in the majority of the cases.Both endoscopic stenting and surgical bypass are considered palliative treatments and,to date,no improvement in survival with either modality has been demonstrated.A tailored therapeutic approach,taking into consideration patient preferences and involving a multidisciplinary team including the therapeutic endoscopist,surgeon,medical oncologist, radiation therapist,and interventional radiologist, should be considered in all cases.

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.

Self-expandable metal stents in patients with postoperative delayed gastric emptying after distal gastrectomy

AIM To investigate the efficacy and safety of endoscopic stent insertion in patients with delayed gastric emptying after gastrectomy.METHODS In this study, we prospectively collected data from patients who underwent stent placement for delayed gastric emptying(DGE) after distal gastrectomy between June 2010 and April 2017, at a tertiary referral academic center. Clinical improvement, complications, and consequences after stent insertion were analyzed.RESULTS Technical success was achieved in all patients(100%). Early symptom improvement was observed in 15 of 20 patients(75%) and clinical success was achieved in all patients. Mean follow-up period was 1178.3 ± 844.1 d and median stent maintenance period was 51 d(range 6-2114 d). During the follow-up period, inserted stents were passed spontaneously per rectum without any complications in 14 of 20 patients(70%). Symptom improvement was maintained after stent placement without the requirement of any additional intervention in 19 of 20 patients(95%).CONCLUSION Endoscopic stent placement provides prompt relief of obstructive symptoms. Thus, it can be considered an effective and safe salvage technique for post-operative DGE.

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.

Resolution of an esophageal leak and posterior gastric wall necrosis with esophageal self-expandable metal stents

The use of weight reduction surgeries has increased over the years with a higher proportion of these surgeries being sleeve gastrectomies,this has been associated with some complications including staple line leaks.We report a 32-year-old male who had undergone a laparoscopic gastric band surgery and subsequently a laparoscopic sleeve gastrectomy,this was complicated by both an staple line leak at the gastroesophageal junction as well as a large(> 4 cm) posterior gastric wall defect due to gastric wall necrosis. We used two co-axially inserted self-expandable stents(SEMS) in the management of this patient,5 stents were used over repeated endoscopy sessions and 20 wk. Both defects had resolved without the need for surgical intervention.This is the first reported case were SEMS are used for both a staple line leak as well as a gastric wall defect.We also review the literature on the use of SEMS in the management of leaks post weight reduction surgeries.

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.

Self-expanding metallic esophageal stents:A long way to go before a particular stent can be recommended

We agree that the covered self-expanding metal stents (SEMSs) fare better than the uncovered stents as recurrent dysphagia due to tumor ingrowth is common with uncovered stent. Recent American College of Gastroenterology Practice Guideline on the Role of Esophageal Stents in Benign and Malignant Diseases concludes that SEMSs cannot be routinely recommended in conjunction with chemo-radiation. The comparison of ultraflex and choostent in the Italian study found no difference in the palliation of dysphagia, rate of complications and survival rate.

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.

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.