Stent under-expansion on the procedure day, a predictive factor for poor oral intake after metallic stenting for gastric outlet obstruction

Endoscopic Ultrasound-Guided Gastroenterostomy versus Enteral Stenting for Malignant Gastric Outlet Obstruction: A Retrospective Propensity Score-Matched Study

BACKGROUND

Endoscopic ultrasound-guided gastroenterostomy (EUS-GE) using lumen apposing metal stent has emerged as a minimally invasive treatment for the management of malignant gastric outlet obstruction (mGOO). We aimed to compare EUS-GE with enteral stenting (ES) for the treatment of mGOO.

METHODS

Patients who underwent EUS-GE or ES for mGOO between June 2017 and June 2023 at two Italian centers were retrospectively identified. The primary outcome was stent dysfunction. Secondary outcomes included technical success, clinical failure, safety, and hospital length of stay. A propensity score-matching analysis was performed using multiple covariates.

RESULTS

Overall, 198 patients were included (66 EUS-GE and 132 ES). The stent dysfunction rate was 3.1% and 16.9% following EUS-GE and ES, respectively (p = 0.004). Using propensity score-matching, 45 patients were allocated to each group. The technical success rate was 100% for both groups. Stent dysfunction was higher in the ES group compared with the EUS-GE group (20% versus 4.4%, respectively; p = 0.022) without differences in clinical efficacy (p = 0.266) and safety (p = 0.085). A significantly shorter hospital stay was associated with EUS-GE compared with ES (7.5 ± 4.9 days vs. 12.5 ± 13.0 days, respectively; p = 0.018). Kaplan-Meier analyses confirmed a higher stent dysfunction-free survival rate after EUS-GE compared with ES (log-rank test; p = 0.05).

CONCLUSION

EUS-GE offers lower rates of stent dysfunction, longer stent patency, and shorter hospital stay compared with ES.

Gastroduodenal Stenting with a Flexible Stent Demonstrates Favorable Clinical Effectiveness despite Gradual Expansion: A Multicenter Prospective Study

AIMS

This study aimed to evaluate the effectiveness and safety of stenting with a flexible braided self-expandable metal stent (SEMS) for unresectable malignant gastric outlet obstruction (GOO).

METHODS

Palliative stenting was prospectively carried out at seven university hospitals between October 2017 and August 2020. All procedures were performed using a flexible branded SEMS of the same brand. The primary endpoint was clinical success rate at 7 days after stenting. Secondary endpoints were procedural success rate, adverse events, recurrent gastric outlet obstruction (RGOO), and patient survival time.

RESULTS

Sixty patients were enrolled. The procedural and clinical success rates were 100% and 90%, respectively. RGOO occurred in 15 cases (25%). Adverse events other than RGOO were found in seven cases (12%). The 50% survival time was 75.5 days (range: 52-97 days). Median expansion rates at 1, 3, and 7 days after stenting were 55%, 65%, and 75%, respectively.

CONCLUSIONS

A flexible braided stent woven with relatively thin wires was used for malignant GOO. Despite a gradual expansion with slightly lower expansile force, the stent functioned sufficiently well and showed favorable results. Clinical Trials Registry ID: UMIN000029496.

How to successfully administer palliative treatment with a stent for malignant gastric outlet obstruction?

Although endoscopic stenting (ES) has been widely used as a less-invasive palliation method for malignant gastric outlet obstruction (GOO), recent reports have highlighted issues related to the procedure. For successful treatment, various aspects must be assessed before considering the practices. First, it is necessary to eliminate cases with contraindications such as coexistence of distal small-bowel obstruction or perforation. Other factors potentially related to clinical failure (i.e., peritoneal carcinomatosis) may require consideration but remain controversial. ES has better short-term outcomes than surgical gastrojejunostomy (GJ). GJ has recently been considered preferable in cases with longer life expectancy because of superior sustainability. Various types of stents are now commercially available, but their ideal structure and mechanical properties have not yet been clarified. Covered metal stent may reduce stent obstruction but is prone to increase stent migration, and its significance remains uncertain. Subsequent chemotherapy after stenting should be considered, as it is expected to prolong patient survival without increasing the risk of adverse events. Furthermore, it may be helpful in preventing tumor ingrowth. In cases with GOO combined with biliary obstruction, biliary intervention is often difficult. Recently, endoscopic ultrasound-guided biliary drainage (EUS-BD) has been widely used as an alternative procedure for endoscopic transpapillary biliary drainage (ETBD). Despite the lack of consensus as to whether ETBD or EUS-BD is preferred, EUS-BD is useful as a salvage technique for cases where ETBD is difficult. To perform stent placement successfully, it is important to pay attention to the above points; however, many remaining issues need to be clarified in the future.

Self-expandable duodenal metal stent placement for the palliation of gastric outlet obstruction over the past 20 years

INTRODUCTION

Duodenal stent placement is a palliative option for management of malignant gastric outlet obstruction (GOO). In the last 20 years, management of gastrointestinal cancers has considerably changed. It is unknown if these changes have affected clinical outcome of duodenal stent placement.

METHODS

Retrospective cohort study conducted in a tertiary referral center. Patients who underwent duodenal stent placement for GOO-symptoms due to a malignant stricture were included. Primary outcome was GOO-symptom free survival. Secondary outcomes included stent-related adverse event rates. Potential explanatory parameters such as period of stent placement (1998-2009 vs 2010-2019), prior treatments, peritoneal deposits, and stricture length were evaluated using multivariable Cox regression analysis.

RESULTS

A total of 147 patients (62 % male; median age 64 years) were included. After a median of 28 days after stent placement, 82 patients (57 %) had recurrent GOO-symptoms. GOO-symptom free survival was significantly lower in 2010-2019 (P < 0.01). Time period was the only independent predictor for reduced GOO-symptom free survival (HR 1.76, P < 0.01). Stent-related adverse event rates increased over time (1998-2009: 31 % vs 2010-2019: 37 %). Prior treatment with chemotherapy and/or radiotherapy was significantly associated with an increased risk of adverse events (OR 2.53, P = 0.02).

CONCLUSIONS

Clinical outcome of duodenal stent placement did not improve over time. The decreased GOO-symptom free survival and increased adverse event rate in more recent years are probably related to the chemo- and/or radiotherapy treatment provided prior to duodenal stent placement.

Development and validation of a risk score for prediction of clinical success after duodenal stenting for malignant gastric outlet obstruction

BACKGROUND

To develop and validate a risk score for predicting clinical success after duodenal stenting using self-expanding metallic stents (SEMS) for malignant gastric outlet obstruction (GOO).

RESEARCH DESIGN AND METHODS

Consecutive patients who underwent duodenal stenting for malignant GOO were evaluated. Potential predictors of clinical success were determined by uni/multivariate logistic regression analysis.Multiplication of the regression coefficients of the logistic regression model by a factor of two and rounding to obtain easy-to-use point numbers enabling the calculation of the score. Using 10-fold cross-validation, the model was internally validated.

RESULTS

One hundred twelve patients were included. Clinical success was achieved in 93 (83.0%) patients. On multivariate logistic regression, selected age ≤65 years (p = 0.05, 1.5 points), stenosis type I (p = 0.04, 3 points), and pancreatic cancer (p = 0.01, 3.5 points) were significant predictors of clinical success. On the Receiver Operating Characteristic (ROC) analysis, a score of 5 had higher specificity and sensitivity.

CONCLUSION

Our score could be useful at identifying, among poor surgical candidates, patients more likely to benefit from SEMS.

Malignant gastric outlet obstruction: Which is the best therapeutic option?

Malignant gastric outlet obstruction (MGOO) is a clinical condition characterized by the mechanical obstruction of the pylorus or the duodenum due to tumor compression/infiltration, with consequent reduction or impossibility of an adequate oral intake. MGOO is mainly secondary to advanced pancreatic or gastric cancers, and significantly impacts on patients' survival and quality of life. Patients suffering from this condition often present with intractable vomiting and severe malnutrition, which further compromise therapeutic chances. Currently, palliative strategies are based primarily on surgical gastrojejunostomy and endoscopic enteral stenting with self-expanding metal stents. Several studies have shown that surgical approach has the advantage of a more durable relief of symptoms and the need of fewer re-interventions, at the cost of higher procedure-related risks and longer hospital stay. On the other hand, enteral stenting provides rapid clinical improvement, but have the limit of higher stent dysfunction rate due to tumor ingrowth and a subsequent need of frequent re-interventions. Recently, a third way has come from interventional endoscopic ultrasound, through the development of endoscopic ultrasound-guided gastroenterostomy technique with lumen-apposing metal stent. This new technique may ideally encompass the minimal invasiveness of an endoscopic procedure and the long-lasting effect of the surgical gastrojejunostomy, and brought encouraging results so far, even if prospective comparative trial are still lacking. In this Review, we described technical aspects and clinical outcomes of the above-cited therapeutic approaches, and discussed the open questions about the current management of MGOO.

Malignant gastric outlet obstruction: Which is the best therapeutic option?

Malignant gastric outlet obstruction (MGOO) is a clinical condition characterized by the mechanical obstruction of the pylorus or the duodenum due to tumor compression/infiltration, with consequent reduction or impossibility of an adequate oral intake. MGOO is mainly secondary to advanced pancreatic or gastric cancers, and significantly impacts on patients’ survival and quality of life. Patients suffering from this condition often present with intractable vomiting and severe malnutrition, which further compromise therapeutic chances. Currently, palliative strategies are based primarily on surgical gastrojejunostomy and endoscopic enteral stenting with self-expanding metal stents. Several studies have shown that surgical approach has the advantage of a more durable relief of symptoms and the need of fewer re-interventions, at the cost of higher procedure-related risks and longer hospital stay. On the other hand, enteral stenting provides rapid clinical improvement, but have the limit of higher stent dysfunction rate due to tumor ingrowth and a subsequent need of frequent re-interventions. Recently, a third way has come from interventional endoscopic ultrasound, through the development of endoscopic ultrasound-guided gastroenterostomy technique with lumen-apposing metal stent. This new technique may ideally encompass the minimal invasiveness of an endoscopic procedure and the long-lasting effect of the surgical gastrojejunostomy, and brought encouraging results so far, even if prospective comparative trial are still lacking. In this Review, we described technical aspects and clinical outcomes of the above-cited therapeutic approaches, and discussed the open questions about the current management of MGOO.

Predictors of self-expanding metallic stent dysfunction in malignant gastric outlet obstruction

INTRODUCTION AND OBJECTIVES

Self-expanding metallic stents (SEMS) are the ideal treatment for malignant gastric outlet obstruction (MGOO) in patients with a short life expectancy, but stent dysfunction is frequent. The primary aim of our study was to identify the predictive factors of SEMS dysfunction in MGOO and the secondary aim was to determine the technical success, clinical success, and nutritional impact after SEMS placement.

MATERIAL AND METHODS

A retrospective, longitudinal study was conducted at the gastrointestinal endoscopy department of the Instituto Nacional de Cancerología in Mexico City. Patients diagnosed with MGOO that underwent SEMS placement within the time frame of January 2015 to May 2018 were included. We utilized the gastric outlet obstruction scoring system (GOOSS) to determine clinical success and SEMS dysfunction.

RESULTS

The study included 43 patients, technical success was 97.7% (n=42), and clinical success was 88.3% (n=38). SEMS dysfunction presented in 30.2% (n=13) of the patients, occurring in<6 months after placement in 53.8% (n=7) of them. In the univariate analysis, the histologic subtype, diffuse gastric adenocarcinoma (p=0.02) and the use of uncovered SEMS (p=0.02) were the variables associated with dysfunction. Albumin levels and body mass index did not increase after SEMS placement. Medical follow-up was a mean 5.8 months (1-24 months).

CONCLUSIONS

SEMS demonstrated adequate technical and clinical efficacy in the treatment of MGOO. SEMS dysfunction was frequent and diffuse type gastric cancer and uncovered SEMS appeared to be dysfunction predictors.

Feasibility and safety of duodenal covered self-expandable metallic stent fixation: an experimental study

BACKGROUND AND AIMS

Migration of duodenal covered self-expandable metallic stents (C-SEMS) is the main cause of stent dysfunction in patients with malignant gastric outlet obstruction. However, the ideal method to prevent migration has not been clarified. We aimed to evaluate the feasibility and safety of duodenal C-SEMS fixation in this experimental study.

METHODS

We used the over-the-scope clip (OTSC), suture, and clip methods to fix duodenal C-SEMS and evaluated the gripping force of each device and invasion depth based on pathological findings.

RESULTS

The OTSC and suturing systems had a significantly higher mean gripping force compared with the clipping system (OTSC vs. clip: 13.2 vs. 1.0 Newtons [N], P < 0.001; suture vs. clip: 8.5 vs. 1.0 N, P < 0.001). OTSC compression was stronger compared with suturing (OTSC vs. suture: 13.2 vs. 8.5 N, P = 0.006). The submucosal layer, but not the muscle layer, was compressed more widely and deeply by OTSC compared with clips based on pathological findings by hematoxylin and eosin staining.

CONCLUSION

Both OTSC and suturing methods used for duodenal C-SEMS fixation were feasible compared with the clipping method. The pathological evaluation of invasion depth indicated that OTSC may be safe even for preventive use. This study suggested that these methods can be applied clinically for duodenal C-SEMS fixation.

The utility and efficacy of self-expandable metal stents for treating malignant gastric outlet obstructions in patients under best supportive care

PURPOSE

Self-expandable metallic stents (SEMSs) may be used to effectively palliate malignant gastric outlet obstructions (GOOs), but their utility and efficacy in patients under best supportive care (BSC) have not been explored.

METHOD

In this multicenter retrospective study, we reviewed data on patients under BSC who underwent endoscopic SEMS placement to treat malignant GOO without chemotherapy. We evaluated the safety and efficacy of the procedure.

RESULTS

We enrolled a total of 208 patients. SEMS placement was technically successful in 207 (99.5%) and clinically successful in 164 (78.8%). The mean procedure time was 25.6 ± 2.8 min. Stent dysfunction later developed in 30 (14.4%) patients, of whom 90% (27/30) underwent reintervention. The procedure-related mortality rate was 1.44%; all deaths were due to pneumonia. Subgroup analysis by Karnofsky performance status (KPS) revealed that neither technical success, stent dysfunction, reintervention rate, procedure-related pneumonia or death, nor death within 14 days differed between patients with good and poor KPS. However, the clinical success rate and the median survival time were significantly lower and shorter, respectively, in those with poor KPS (p < 0.001).

CONCLUSIONS

Duodenal SEMS placement is an effective palliative treatment for malignant GOO in BSC patients. Although the GOO score did not dramatically improve in patients with poor KPS, the procedure was safe and palliatively feasible. Procedure-related pneumonia was fatal; thus, it is essential to proceed with great caution.

TRIAL REGISTRATION

Clinical trial registration number: UMIN000028367.

Covered duodenal self-expandable metal stents prolong biliary stent patency in double stenting: The largest series of bilioduodenal obstruction

BACKGROUND AND AIM

Endoscopic biliary and duodenal stenting (DS; double stenting) is widely accepted as a palliation therapy for malignant bilioduodenal obstruction. The aim of the current study was to investigate the patency and adverse events of duodenal and biliary stents in patients with DS.

METHODS

Patients who underwent DS from April 2004 to March 2017 were analyzed retrospectively with regard to clinical outcomes and predictive factors of recurrent biliary and duodenal obstruction (recurrent biliary obstruction [RBO] and recurrent duodenal obstruction [RDO]).

RESULTS

A total of 109 consecutive patients was enrolled. Technical success of DS was achieved in 108 patients (99.1%). Symptoms due to biliary and duodenal obstruction were improved in 89 patients (81.7%). RBO occurred in 25 patients (22.9%) and RDO in 13 (11.9%). The median times to RBO and RDO from DS were 87 and 76 days, respectively. Placement of a duodenal uncovered self-expandable metal stent (U-SEMS) was significantly associated with RBO in the multivariable analysis (P = 0.007). Time to RBO was significantly longer in the duodenal covered self-expandable metal stent group than in the U-SEMS group (P = 0.003). No predictive factors of RDO were detected, and duodenal stent type was not associated with the time to RDO (P = 0.724).

CONCLUSIONS

Double stenting was safe and effective for malignant bilioduodenal obstruction. Duodenal U-SEMS is a risk factor for RBO. The covered self-expandable metal stent is the preferred type of duodenal SEMS in patients with DS (Clinical trial registration number: UMIN000027606).

Metallic Stent Expansion Rate at Day One Predicts Stent Patency in Patients with Gastric Outlet Obstruction

BACKGROUND AND AIMS

Self-expandable metallic stent insertion has been a mainstream treatment for relieving the obstructive symptoms of malignant gastric outlet obstruction (MGOO), a late-stage complication of gastrointestinal malignancies. This study aims to investigate the predictive value of stent expansion rates in clinical outcomes in patients with MGOO.

METHODS

Eighty-seven patients with inoperable MGOO receiving metallic stents were reviewed retrospectively from April 2010 to December 2014. Clinical outcomes, predictors of stent patency, and survival were analyzed.

RESULTS

The technical and clinical success rates were 100 and 94.3%, respectively. The median stent patency time was 114 days (range 13-570 days). The median survival time was 133 days (range 13-1145 days). Stent dysfunctions occurred in 28 patients (32.2%), with restenosis accounting for the majority (82%). The stent expansion rate ≥75% at Day 1 predicted the stent patency [hazard ratio (HR) 0.12, P = 0.04]. However, it did not correlate with survival. Non-gastric cancer origins (HR 2.41, P = 0.002) and peritoneal carcinomatosis (HR 2.54, P = 0.001) correlated with poor survival. However, post-stent chemotherapy (HR 0.55, P = 0.03) was related to better outcome. The comparison of clinical outcomes of first and second stent insertions showed no significant difference in the stent expansion rate either at Day 0 and Day 1 (P = 0.97 and P = 0.57).

CONCLUSIONS

Self-expandable metallic stent insertion is a safe and effective treatment for relieving the obstructive symptoms. The stent expansion rate ≥75% at Day 1 is a novel stent-related predictor of stent patency.

Novel characteristics of traction force in biliary self-expandable metallic stents

BACKGROUND AND AIM

In recent years, knowledge concerning the mechanical properties of self-expandable metallic stents (SEMS) has increased. In a previous study, we defined traction force and traction momentum and reported that these characteristics are important for optimal stent deployment. However, traction force and traction momentum were represented as relative values and were not evaluated in various conditions. The purpose of the present study was to measure traction force in various situations assumed during SEMS placement.

METHODS

Traction force and traction momentum were measured in non-stricture, stricture, and angled stricture models using in-house equipment.

RESULTS

Stricture and angled stricture models had significantly higher traction force and traction momentum than those of the non-stricture model (stricture vs non-stricture: traction force, 7.2 N vs 1.4 N, P < 0.001; traction momentum, 237.8 Ns vs 62.3 Ns, P = 0.001; angled stricture vs non-stricture: traction force, 7.4 N vs 1.4 N, P < 0.001; traction momentum, 307.2 Ns vs 62.3 Ns, P < 0.001). Traction force was variable during SEMS placement and was categorized into five different stages, which were similar in both the stricture and angled stricture models.

CONCLUSIONS

We measured traction force and traction momentum under simulated clinical conditions and demonstrated that strictures and the angular positioning of the stent influenced the traction force. Clinicians should be aware of the transition of the traction force and should schedule X-ray imaging during SEMS placement.

Recent advancements in stent therapy in patients with malignant gastroduodenal outlet obstruction

Gastric outlet obstruction (GOO) is one of severe comorbidities caused by many kinds of malignant diseases and is associated with not only degradation of patients' quality of life but also mortality. Although surgical bypass is one of the main therapies for malignant GOO, it is often difficult to perform in end-stage patients. The deployment of self-expandable metallic stents (SEMSs) has recently become a viable alternative to surgical bypass for malignant GOO. This technique is less invasive and more effective, particularly in patients with poor prognoses. Many reports have referred to the feasibility, effectiveness, and safety of the placement of SEMSs for malignant GOO. According to these reports, the rates of technical and clinical success were reported to be relatively high and the rate of adverse events to be acceptable. However, precautions against severe adverse events such as massive bleeding and perforation are necessary. Several reports have described the differences in clinical results among different kinds of SEMSs. The presence of a covered design for SEMSs may affect the patency of SEMSs and the rate of stent dysfunction. Selection of the SEMS according to axial force may affect successful achievement of long patency of SEMSs and avoidance of gastroduodenal perforation at the bending site of the duodenum. Compared with high technical success rates nearing 100%, clinical success rates were usually lower than technical success. Therefore, determination of predictive factors for failure of clinical success is important. Several papers reported that low performance status could be associated with failure of clinical success. However, the association of clinical success with other factors such as carcinomatosa and ascites remains controversial, which is a problem to be solved. Reintervention with SEMS using the stent-in-stent method after stent dysfunction can be performed effectively as well as placement of the first SEMS.

Predictors of outcomes in patients undergoing covered and uncovered self-expandable metal stent placement for malignant gastric outlet obstruction: a multicenter study

BACKGROUND AND AIMS

Uncovered self-expandable metal stents (U-SEMSs) and covered self-expandable metal stents (C-SEMSs) are available for palliative therapy for malignant gastric outlet obstruction (GOO). However, clinical differences and indications between the 2 types of SEMSs have not been elucidated.

METHODS

We retrospectively compared 126 patients with U-SEMS and 126 patients with C-SEMSs with regard to clinical outcome and factors predictive of clinical improvement after SEMSs placement.

RESULTS

No significant difference was observed between the U-SEMS and C-SEMS groups with respect to technical success, clinical success, GOO score, or time to stent dysfunction. Stent migration was significantly more frequent in patients with C-SEMSs (U-SEMSs, .79%; C-SEMSs, 8.73%; P = .005). Karnofsky performance status, chemotherapy, peritoneal dissemination, and stent expansion ≤ 30% were associated significantly with poor GOO score improvement in multivariable analyses, but stent type was not (P = .213). In subgroup analyses, insufficient (≤30%) stent expansion was an independent factor in patients with U-SEMSs (P = .041) but not C-SEMSs. In the insufficient stent expansion subgroup, C-SEMSs was associated significantly with superior clinical improvement compared with U-SEMSs (P = .01). Insufficient stent expansion was observed more frequently in patients with GI obstruction because of anastomotic sites or metastatic cancer (44.8% [13/29], P = .001).

CONCLUSIONS

No clinical difference, apart from stent migration, was observed between patients with U-SEMSs and C-SEMSs. GI obstruction because of an anastomotic site or metastatic cancer may be an indication for C-SEMS use to improve oral intake after SEMSs placement.

The location of obstruction predicts stent occlusion in malignant gastric outlet obstruction

BACKGROUND

Gastric outlet obstruction (GOO) can occur with locally invasive or metastatic cancer involving the upper gastrointestinal tract at the pylorus or the duodenum. Endoscopic management with self-expanding metal stents (SEMSs) is often the preferred palliative approach. Stent occlusion is a common reason for failure and reintervention. We set out to determine whether the location of the malignant obstruction is associated with the angulation of the stent and can predict stent occlusion.

METHODS

We performed a retrospective review of consecutive patients who underwent successful duodenal stenting with SEMS for malignant GOO between 2006 and 2015 at a large advanced endoscopy referral center. We determined the location of obstruction, the stent angle, and the rate of technical and clinical success of stent placement. We then identified cases of subsequent stent occlusion confirmed by endoscopic evaluation.

RESULTS

A total of 100 consecutive patients were included in the study; 91 of these patients had enough data to evaluate SEMS occlusion. A total of 21 patients (23%) developed stent occlusion with a median time of 39 days. The risk of occlusion sequentially increased as the obstruction occurred more distally from the antrum to the third or fourth portion of the duodenum (p = 0.006). This relationship was maintained after controlling for stent angle (p = 0.05).

CONCLUSIONS

A distal location of malignant GOO was strongly predictive of stent occlusion, independent of stent angle. This may be due to longer and more complex distal obstructions, along with foreshortening of the stent during placement and tumor infiltration. If replicated, these results will have implications for endoscopic practice and future device development.

Outcome of self-expandable metallic stent deployment in patients with malignant gastroduodenal outlet obstruction and Niti-S and WallFlex comparison: a multicenter retrospective clinical study

OBJECTIVES

Several studies report on the outcomes of self-expandable metallic stents (SEMSs) deployment for malignant gastric outlet obstruction (GOO). However, data was mostly based on the analysis of single-center studies including only a small number of patients. This study aimed to evaluate clinical outcomes after the deployment of SEMS in patients with malignant GOO and to compare the clinical outcomes of two metallic stents with different designs.

METHODS

Altogether 125 consecutive patients from five institutions were included. Clinical outcomes were evaluated according to technical success, clinical success, stent patency period, survival period and complications. A comparison of clinical outcomes between Niti-S pyloric/duodenal and WallFlex duodenal stents was also undertaken.

RESULTS

Rates for clinical and technical success were 100% and 92.0%, respectively. The median stent patency and survival periods were 72.0 days (range 3-775 days) and 75.0 days (range 3-775 days), respectively. The rate of overall adverse events was 28.8%. The rate of stent dysfunction was 16.8%, and that of adverse events, except stent dysfunction was 12.0%. Massive bleeding occurred in two patients as a late complication. The clinical success rate for Niti-S stent was significantly higher than that for WallFlex stent (96.2% vs 84.8%, P = 0.023).

CONCLUSIONS

We successfully deployed a SEMS in malignant GOO. The selection of a SEMS with a lower axial force may be important for patients to resume the oral food intake. Additionally, consideration must be given to the appropriate management of fatal bleeding as a late complication.

Self-expandable metal stents for malignant gastric outlet obstruction: A pooled analysis of prospective literature

AIM: To provide an overview of the clinical outcomes of self-expandable metal stent (SEMS) placement for malignant gastric outlet obstruction (MGOO).

METHODS: A systematic literature search was performed in PubMed of the literature published between January 2009 and March 2015. Only prospective studies that reported on the clinical success of stent placement for MGOO were included. The primary endpoint was clinical success, defined according to the definition used in the original article. Data were pooled and analyzed using descriptive statistics. Subgroup analyses were performed for partially covered SEMSs (PCSEMSs) and uncovered SEMSs (UCSEMSs) using Fisher’s exact test.

RESULTS: A total of 19 studies, including 1281 patients, were included in the final analysis. Gastric (42%) and pancreatic (37%) cancer were the main causes of MGOO. UCSEMSs were used in 76% of patients and PCSEMSs in 24%. The overall pooled technical success rate was 97.3% and the clinical success rate was 85.7%. Stent dysfunction occurred in 19.6% of patients, mainly caused by re-obstruction (12.6%) and stent migration (4.3%), and was comparable between PCSEMSs and UCSEMSs (21.2% vs 19.1%, respectively, P = 0.412). Re-obstruction was more common with UCSEMSs (14.9% vs 5.1%, P < 0.001) and stent migration was more frequent after PCSEMS placement (10.9% vs 2.2%, P < 0.001). The overall perforation rate was 1.2%. Bleeding was reported in 4.1% of patients, including major bleeding in 0.8%. The median stent patency ranged from 68 to 307 d in five studies. The median overall survival ranged from 49 to 183 d in 13 studies.

CONCLUSION: The clinical outcomes in this large population showed that enteral stent placement was feasible, effective and safe. Therefore, stent placement is a valid treatment option for the palliation of MGOO.