Metal Stents Research Articles

Lumen-apposing metal stents and their emerging role in therapeutic endoscopic ultrasound

The field of therapeutic endoscopic ultrasound (EUS) has expanded significantly in the past 2 decades, thanks in part to the invention and wide use of lumen-apposing metal stents (LAMS). LAMS are used as alternatives to surgical or interventional radiological procedures, and yield excellent outcomes. Initially, their use was limited to management of various types of pancreatic fluid collections, including walled-off necrosis or pseudocysts. In recent years, the indications have expanded to biliary drainage, particularly in cases of malignant bile duct obstruction. LAMS are also used in gastric outlet obstruction and to access bile duct in patients with surgically altered anatomy. This clinical review aims to briefly expand on these indications and discuss the supporting literature for use of LAMS.

Advancements in Endovascular Treatment of Extracranial Carotid Artery Aneurysms

Traditionally, extracranial carotid artery aneurysms or pseudoaneurysms (ECCAs) have been managed through open surgical repair. Recent literature highlights the increasing success of endovascular techniques in treating ECCAs. Our study explores our center's experience with endovascular management of ECCAs, including the innovative use of Transcarotid Artery Revascularization (TCAR) at a tertiary care center. We performed a retrospective analysis of patients with ECCAs who underwent endovascular intervention at a single institution. We examined our database from the period of 2010 to 2024. Our treatment modalities have expanded to include covered stenting, stent-assisted coil embolization, braided stents, overlapping closed-cell stents, and most recently Transcarotid Artery Revascularization (TCAR). There were 29 extracranial carotid artery aneurysms in 27 patients treated with various endovascular modalities. The average age was 67.6 years, with 17 (63.0%) males and 10 (37.0%) females. 8 (29.6%) patients had prior ipsilateral carotid intervention. 9 (31.0%) aneurysms were symptomatic. The most common etiology was idiopathic, with 16 (55.2%) aneurysms being spontaneous. Treatment modalities included: 2 (6.9%) treated with covered stents, 2 (6.9%) with stent-assisted embolization, 3 (10.3%) with flow-diverting braided stents, 3 (10.3%) with embolization or ligation alone, 17 (58.6%) with overlapping bare metal stents via femoral or radial access, and 2 (6.9%) with overlapping bare metal stents via TCAR. Technical success was achieved in all patients. The mean follow-up duration was 236 days (range: 2 to 3039 days). No perioperative or post-operative complications occurred, including no neurological deficits or embolic events. All patients were discharged on post-operative day 1 or 2. All 29 (100%) stents maintained vessel patency on follow-up imaging, and exclusion of ECCAs was confirmed on post-procedure surveillance imaging. Our study highlights that endovascular therapy is effective in managing ECCAs, with high patency rates and a favorable procedural safety profile.

Successful Factors for Improving Aortic Remodeling with Thoracic Endovascular Repair and Bare Stent Extension

ObjectiveProximal ExTension to Induce COmplete ATtachment (PETTICOAT), which utilizes downstream bare metal stents for structural support, demonstrates potential, yet its adoption is limited by variable outcomes. This study elucidates the potential of PETTICOAT in aortic dissection, emphasizing the determinants that guide patient selection. MethodsA retrospective analysis of 60 patients who underwent full PETTICOAT for aortic dissections was conducted. A multivariate logistic regression model identified predictors of favorable aortic remodeling. Patients underwent standardized follow-up with CT scans to assess size, volumetric changes, and anatomical conditions. Selection criteria included full PETTICOAT application and a minimum three-month follow-up. Demographics, preoperative conditions, and procedural details were collected and analyzed. ResultsThe analysis identified predictors of favorable aortic remodeling, including age over 60, a larger downstream aorta stent graft, a smaller abdominal aorta (<450mm2), and oral angiotensin II receptor blocker (ARB) administration. Over a median 47.5-month follow-up, survival rates in the favorable remodeling (97.3%) and unfavorable groups (100%) were similar. Downstream aortic event-free survival rates did not significantly differ (89.2% vs. 73.9%), although the unfavorable group had a relatively higher incidence of distal stent-induced new entries (26.1% vs. 8.1%). ConclusionsThe PETTICOAT concept effectively enhances aortic remodeling in complex aortic dissections. Predictors for favorable remodeling, including age, stent graft sizing, aortic diameter, and ARB therapy, offer insights for optimizing patient selection. This approach improves survival outcomes, mitigates risks associated with untreated aortic segments, and provides a minimally invasive solution for aortic dissections. Despite some outcome variations, the technique holds promise for addressing the challenges of aortic dissections, with the potential for further refinement in patient selection and technique application.

COMPARISON OF DRUG-ELUTING STENTS VERSUS BARE-METAL STENTS FOR THE TREATMENT OF CORONARY ARTERY DISEASE

Coronary artery disease is a condition that affects millions of people worldwide and can lead to serious complications such as heart attack or stroke. Objectives: The study compares drug-eluting stents to bare-metal stents for treating coronary artery disease. Methods: The present study aimed to compare the efficacy and safety of drug-eluting stents (1) versus bare metal stents (BMS) for the treatment of coronary artery disease (CAD). The study was conducted at Cardiology Department Hayat Abad Medical Complex Peshawar Pakistan, from 01 January 2022 till 30 June 2022. The study included a total of 384 patients with CAD who underwent percutaneous coronary intervention (PCI) with either DES or BMS. Results: The study included a total of 384 patients with CAD who underwent PCI with either DES or BMS. The mean age of the study participants was 58.2 ± 9.4 years, and 75.8% were male. The baseline characteristics, including demographic data, clinical presentation, cardiovascular risk factors, and angiographic findings, were comparable between the two groups. Conclusion: In conclusion, our study contrasting medication-eluting stents versus exposed metal stents for the treatment of coronary supply route sickness found that drug-eluting stents were related to a lower chance of unfriendly heart occasions, including objective vessel revascularization, myocardial dead tissue, and cardiovascular demise, contrasted with uncovered metal stents.

Safety and efficacy of conventional compared to segmented esophageal fully covered self-expanding metal stents: a retrospective multicenter case-control study.

Segmented self-expanding metal stents (SEMS) are an alternative to conventional unsegmented SEMS in the treatment of esophageal strictures. Due to their segmented design, they may adapt better to the surrounding structures making them less likely to migrate or cause trauma. We examined if there are clinically relevant differences between segmented and conventional esophageal SEMS in benign and malignant stenosis in terms of their functionality and safety. We performed a multicenter, retrospective case-control study of segmented and conventional SEMS implantations in esophageal stenosis. Outcome parameters were adverse events such as migration, occlusion, and severe complications (i.e., bleeding and perforation). 79 segmented SEMS were identified and compared to 79 conventional SEMS implantations. Groups were similar in terms of age, gender, and etiology. We observed 13.9% severe complications (SEMS-associated clinically significant bleeding or perforation) in the conventional SEMS group compared to 3.8% in the segmented SEMS group. This difference was statistically significant (p = 0.025). Rates of migration and occlusion were similar between both groups. Likewise, there was no significant difference in terms of short-term (30days) clinical success. In this first controlled analysis, segmented SEMS were associated with fewer severe clinical complications compared to conventional SEMS.

Optimization stages of transjugular intrahepatic portosystemic shunt technique as a treatment method for portal hypertension complications

Aim. To describe the milestones to optimize of the technique of transjugular intrahepatic portosystemic shunt.Materials and methods. The PubMed and Embase databases, the Web of Science platform, the Google Scholar retrieval system, the Cochrane Database of Systematic Reviews, the eLIBRARY.RU scientific electronic library, and the reference lists were used to search for articles. Articles corresponding to the aim of the review were selected for 1969-2023. The inclusion criteria were limited to technical solutions related to optimize of the technique of transjugular intrahepatic portosystemic shunt.Results. Innovative ideas, subsequent experimental studies and preliminary experience in liver cirrhosis patients contributed to the introduction of transjugular intrahepatic portosystemic shunt into clinical practice. At the moment, the main achievement to optimize of the technique of transjugular intrahepatic portosystemic shunt is progress in the qualitative characteristics of stents. The transition from bare metal stents to expandable polytetrafluoroethylene-covered stent graft made it possible to largely prevent shunt dysfunction. However, the issue of its optimal diameter, contributing to an effective reduction of portal pressure without the risk of developing hepatic encephalopathy, which is one of the most common complications of transjugular intrahepatic portosystemic shunt, remains relevant.Conclusion. Further to optimize of the technique of transjugular intrahepatic portosystemic shunt, as well as careful selection of patients based on cognitive indicators, nutritional status and assessment of liver function will reduce the incidence of hepatic encephalopathy and improve treatment results.

Manufacturing, Processing, and Characterization of Self-Expanding Metallic Stents: A Comprehensive Review.

This paper aims to review the State of the Art in metal self-expanding stents made from nitinol (NiTi), showing shape memory and superelastic behaviors, to identify the challenges and the opportunities for improving patient outcomes. A significant contribution of this paper is its extensive coverage of multidisciplinary aspects, including design, simulation, materials development, manufacturing, bio/hemocompatibility, biomechanics, biomimicry, patency, and testing methodologies. Additionally, the paper offers in-depth insights into the latest practices and emerging trends, with a special emphasis on the transformative potential of additive manufacturing techniques in the development of metal stents. By consolidating existing knowledge and highlighting areas for future innovation, this review provides a valuable roadmap for advancing nitinol stents.

Drug-eluting stent and drug-coated balloon for in-stent restenosis: A meta-analysis

&lt;p&gt;The optimal strategy for patients with in-stent restenosis (ISR) is controversial. We aimed to compare the effects of a drug-coating balloon (DCB) and drug-eluting stent (DES) in ISR treatment.&lt;strong&gt; &lt;/strong&gt;Clinical trials were extensively collected, and retrieved items were screened for inclusion. Both clinical (major adverse cardiac event (MACE); myocardial infarction (MI); and target lesion revascularization (TLR) and angiographic (minimal lumen diameter (MLD), and stenosis relative to reference lumen diameter (SRLD) endpoints were extracted and compared. MACE and MI were not significantly different between the groups. Pooled results of TLR showed a marginal effect that DES was superior to DCB (13.50% for DCB vs&lt;em&gt;.&lt;/em&gt; 11.17% for DES, RR = 1.256, 95% CI: 0.997 to 1.583, &lt;em&gt;P&lt;/em&gt; = 0.053), with heterogeneity across studies (&lt;em&gt;I&lt;/em&gt;&lt;sup&gt;2&lt;/sup&gt; = 42.0%, Cochrane &lt;em&gt;Q&lt;/em&gt;-test = 0.069). Meta-regression identified bare metal stent (BMS) or drug eluting stents (DES) implanted in the previous intervention and proportions of diabetes in the DCB group as sources of heterogeneity. DES implantation also significantly improved angiographic outcomes (WMD for MLD: −0.318, 95% CI: −0.424 to −0.213, &lt;em&gt;P&lt;/em&gt;&lt;em&gt; &lt;/em&gt;&amp;lt; 0.001; WMD for SRLD: 6.164%, 95% CI: 4.915% to 7.412%, &lt;em&gt;P&lt;/em&gt;&lt;em&gt; &lt;/em&gt;&amp;lt; 0.001). All DES, including everolimus-eluting ones, did not benefit BMS-ISR patients compared with DCB treatment.&lt;strong&gt; &lt;/strong&gt;DES implantation, which is superior to DCB angioplasty only in DES-ISR patients, should be preferred in the DES-ISR population to reduce TLR. DCB may be preferred in BMS-ISR to avoid increasing stent layers.&lt;/p&gt;

Stent Placement After Percutaneous Recanalization of Superior Vena Cava Stenosis in Maintenance Hemodialysis Patients.

This study aimed to evaluate the efficacy and safety of stent placement after percutaneous recanalization of superior vena cava (SVC) stenosis in maintenance hemodialysis patients. Adult maintenance hemodialysis patients hospitalized at a university-affiliated tertiary hospital due to SVC stenosis from January 2016 to June 2023 were prospectively included. The efficacy and safety of percutaneous blunt/sharp SVC recanalization combined with SVC stent placement were observed. The patients' demographic information and laboratory examination data, stent placement success rate, surgery-related complications, and long-term vascular access patency rate were also recorded and analyzed. The study was approved by the institutional ethics committee (2015-201) and registered at http://www.chictr.org.cn (registry number: ChiCTR-ONN-16007790). A total of 58 patients were included in the study with an average age of 54.79±13.42 years. Percutaneous SVC recanalization was successful in 53 cases, with a success rate of 91.38%, including 37 cases of traditional recanalization and 16 cases of sharp recanalization. Among 53 hemodialysis patients who underwent SVC recanalization, 14 patients successfully received covered stents and 38 patients received bare metal stents, achieving a stent placement success rate of 98.1%. One patient encountered stent displacement into the heart immediately after implantation, causing intra-operative cardiac tamponade, who was successfully rescued by thoracotomy. Fifty-two patients were followed-up for median period of 26 months (cuffed catheter: 25 patients, arteriovenous fistula [AVF]: 27 patients). The overall 2-year vascular access patency rate was 33.2% (cuffed catheter: 22.2%, AVF: 41.7%, p=0.414). There was no statistically significant difference in the 2-year vascular access patency rate between the traditional recanalization group and the sharp recanalization group (34.1% vs 31.1%, p=0.731) and between bare metal stent group and covered stent group (38.1% vs 21.4%, p=0.248). Percutaneous SVC recanalization with stent placement is an effective treatment strategy that can provide viable vascular access for maintenance hemodialysis patients with SVC stenosis. Cautions should be paid to potential life-threatening complications such as stent displacement and cardiac tamponade. Superior vena cava (SVC) stenosis is a common central venous occlusive lesion in maintenance hemodialysis patients. Whether stent should be implanted simultaneously following SVC recanalization is still lacking research. This pilot cohort study suggested that percutaneous SVC recanalization with stent placement was an effective treatment strategy which provides satisfactory vascular access for hemodialysis. We further found that SVC sharp recanalization with subsequent stent implantation was a feasible treatment, with the 2-year vascular access patency comparable to the traditional SVC recanalization group. This study also highlighted endovascular SVC recanalization should be performed with caution, and appropriate balloon sizes should be selected to avoid SVC rupture or stent displacement.

Endoscopic biliary drainage for distal bile duct obstruction due to pancreatic cancer.

Approximately 60% of pancreatic cancers occur in the pancreatic head and may present as obstructive jaundice due to bile duct invasion. Obstructive jaundice often leads to poor general conditions and acute cholangitis, interfering with surgery and chemotherapy and requiring biliary drainage. The first choice of treatment for biliary drainage is the endoscopic transpapillary approach. In unresectable tumors, self-expandable metal stents (SEMSs) are most commonly used and are classified into uncovered and covered SEMSs. Recently, antireflux metal stents and large- or small-diameter SEMSs have become commercially available, and their usefulness has been reported. Plastic stents are infrequently used in patients with resectable biliary obstruction; however, owing to the recent trend in preoperative chemotherapy, SEMSs are frequently used because of the long time to recurrent biliary obstruction. Endoscopic ultrasound-guided biliary drainage (EUS-BD) is often performed in patients who are not eligible for the transpapillary approach, and favorable outcomes have been reported. Different EUS-BD techniques and specialized stents have been developed and can be safely used in high-volume centers. The indications for EUS-BD are expected to further expand in the future.

Evolution of Atomic-Level Interfacial Fracture Mechanics in Magnesium-Zinc Compounds Used for Bioresorbable Vascular Stents.

Bioresorbable magnesium-metal vascular stents are gaining popularity due to their biodegradable nature and good biological and mechanical properties. They are also suitable candidate materials for biodegradable stents. Due to the rapid degradation rate of Mg metal vascular scaffolds, a Mg/Zn bilayer composite was formed by a number of means, such as magnetron sputtering and physical vapor deposition, thus delaying the degradation time of the Mg metal vascular scaffolds while providing good radial support for the stenotic vessels. However, the interlaminar compounds at the metal interface have an essential impact on the mechanical properties of the bi-material interface, especially the cracking and delamination of the Mg matrix Zn coating vascular stent in the radially expanded process layer. Intermetallic compounds (IMCs) are commonly found in dual-layer composites, such as Mg/Zn composites and multi-layer structures. They are frequently overlooked in simulations aiming to predict mechanical properties. This paper analyses the interfacial failure processes and evolutionary mechanisms of interfacial fracture mechanics of a Mg/Zn interface with an intermetallic compound layer between coated Zn and Mg matrix metallic vascular stents. The simulation results show that the fracture mode in the Mg/Zn interface with an intermetallic compound involves typical ductile fracture under static tensile conditions. The dislocation line defects mainly occur on the side of the Mg, which induces the Mg/Zn interfacial crack to expand along the interface into the pure Mg. The stress intensity factor and the critical strain energy release rate decrease as the intermetallic compound layer's thickness gradually increases, indicating that the intensity of stress and the force of the crack extending and expanding along the crack tip are weakened. The presence of intermetallic compounds at the interface can significantly strengthen the mechanical properties of the material interface and alleviate the crack propagation between the interfaces.

Biliary drainage in patients with malignant distal biliary obstruction: results of an Italian consensus conference

BackgroundMalignant Distal Biliary Obstruction (MBDO) is a common event occurring along the natural history of both pancreatic cancer and cholangiocarcinoma. Epidemiological and biological features make MBDO one of the key elements of the clinical management of patients suffering for of pancreatic cancer or cholangiocarcinoma. The development of dedicated biliary lumen-apposing metal stents (LAMS) is changing the clinical work up of patients with MBDO. i-EUS is an Italian network of clinicians and scientists with a special interest in biliopancreatic endoscopy, EUS in particular.MethodsThe scientific methodology was chosen in line with international guidance and in a fashion similar to those applied by broader scientific associations. PICO questions were elaborated and subsequently voted by a broad panel of experts within a simplified Delphi process.Results and conclusionsThe manuscripts describes the results of a consensus conference organized by i-EUS with the aim of providing an evidence based-guidance for the appropriate use of the techniques in patients with MBDO.

Percutaneous Endoscopic Colostomy to Relieve Malignant Bowel Obstruction.

Malignant bowel obstruction due to peritoneal carcinomatosis is a common problem. When surgery is not feasible in the context of a high intraperitoneal tumour burden, other techniques are required. We report the case of a 67-year-old female with malignant obstruction of the ascending colon. Following an unsuccessful surgical attempt, decompression was successfully achieved via percutaneous endoscopic colostomy using a lumen-apposing metal stent. The patient was able to resume a full oral diet within 2 days. However, local inflammatory complications arose due to faecal contamination of the sutures. Once the sutures were removed, no further interventions were required. Percutaneous endoscopic colostomy is a safe and viable alternative for decompression in malignant bowel obstruction when surgery is not feasible. However, limitations include the risk of local infection due to sutures and its applicability only in cases with distal stenosis. Malignant bowel obstruction is a frequent challenge in palliative care.Percutaneous colostomy with a lumen-apposing metal stent (LAMS) is a safe and effective option to relieve bowel obstruction.Percutaneous colostomy with a LAMS remains patent in the long term.

Outcomes of multi-hole self-expandable metal stents versus fully covered self-expandable metal stents for malignant distal biliary obstruction in unresectable pancreatic cancer.

The multi-hole self-expandable metal stent (MHSEMS) is a novel SEMS with multiple small side holes on the covering membrane to prevent stent migration while minimizing tumor ingrowth. This study aimed to evaluate the clinical outcomes of MHSEMS in comparison with conventional covered SEMS (c-CMS). Consecutive patients with unresectable pancreatic cancer who underwent initial SEMS placement (MHSEMS or c-CMS) for malignant distal biliary obstruction were analyzed. Technical success, clinical success, causes of recurrent biliary obstruction (RBO), non-RBO adverse events, time to RBO (TRBO), and endoscopic reintervention were compared between groups. A total of 65 patients were included (MHSEMS: 27, c-CMS: 38). The technical success, clinical success, and non-RBO adverse event rates were similar between groups. Although stent migration was less frequently observed in the MHSEMS group (0% vs. 17.6%, p = 0.032), overall RBO rates were similar between groups (53.8% vs. 55.9%, p > 0.99). The most common cause of RBO within 14 days in the MHSEMS group was non-occlusion cholangitis. Median TRBO was significantly shorter in the MHSEMS group (101 vs. 227 days, p = 0.030) and MHSEMS was an independent predictor for shorter TRBO in multivariate analysis (hazard ratio, 2.27; 95% confidence interval, 1.06-4.86; p = 0.034). Outcomes after endoscopic interventio were not significantly different between groups. Stent removal was successful in all attempted cases in both groups. MHSEMS was associated with a significantly shorter TRBO compared to c-CMS. Further modifications of the present MHSEMS may be needed.

Radiation-Emitting metallic stent for unresectable bismuth type III or IV perihilar cholangiocarcinoma: a multicenter randomized trial

Background &amp; Aims: Self-expandable metallic stents (SEMSs) have been recommended for patients with unresectable malignant biliary obstruction while radiation-emitting metallic stents (REMSs) loaded with 125I seeds have recently been approved to provide longer patency and overall survival in malignant biliary tract obstruction. This trial is to evaluate the efficacy and safety of REMS plus hepatic arterial infusion chemotherapy (REMS-HAIC) versus SEMS plus HAIC (SEMS-HAIC) for unresectable perihilar cholangiocarcinoma (pCCA). Methods: This multicenter randomized controlled trial recruited patients with unresectable Bismuth type III or IV pCCA between March 2021 and January 2023. Patients were randomly assigned (1:1 ratio) to receive either REMS-HAIC or SEMS-HAIC using permuted block randomization, with a block size of six. The primary endpoint was overall survival (OS). The secondary endpoints were time to symptomatic progression (TTSP), stent patency, relief of jaundice, quality of life, and safety. Results: A total of 126 patients were included in the intent-to-treat population, with 63 in each group. The median OS was 10.2 months versus 6.7 months (P=0.002). The median TTSP was 8.6 months versus 5.4 months (P=0.003). The median stent patency was longer in the REMS-HAIC group than in the SEMS-HAIC group (P=0.001). The REMS-HAIC group showed better improvement in physical functioning scale (P&lt;0.05) and fatigue symptoms (P&lt;0.05) when compared to the SEMS-HAIC group. No significant differences were observed in relief of jaundice (85.7% vs. 84.1%; P=0.803) or the incidence of grade 3 or 4 adverse events (9.8% vs. 11.9%; P=0.721). Conclusion: REMS plus HAIC showed better OS, TTSP, and stent patency compared with SEMS plus HAIC in patients with unresectable Bismuth type III or IV pCCA with an acceptable safety profile.

Unblocking a terminolateral anastomosis on an interposed coloplasty for caustic esophagitis: placement of a lumen-apposing metal stent to straighten the lumen

Unblocking a terminolateral anastomosis on an interposed coloplasty for caustic esophagitis: placement of a lumen-apposing metal stent to straighten the lumen

Failed endoscopic ultrasound-guided gallbladder drainage across the duodenal covered metallic stent salvaged by using a forward-viewing linear echoendoscope.

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The Midterm Outcomes of Endovascular Therapy for Femoropopliteal Lesions via Drug-Coated Balloon, Directional Atherectomy and Bare Metal Stent Angioplasty.

This study investigated the midterm primary patency of drug-coated balloons (DCBs), directional atherectomy plus balloon angioplasty (DA), and bare metal stent (BMS) angioplasty for the treatment of femoropopliteal lesions. This two-center retrospective cohort study included 105 patients (110 limbs) undergoing DCB, DA, and BMS angioplasty-32 patients (34 limbs), 31 patients (32 limbs), and 42 patients (44 limbs), respectively. The demographic, baseline, and procedure data were collected, and the complications and midterm outcomes (patency, amputation-free survival, and clinically driven target lesion revascularization rates) were analyzed. All three procedures achieved a 100% success rate. Significant improvements were noted in ankle brachial index, walking distance, and Rutherford classification at 30 days post-procedure (p < 0.001), with no differences or severe complications among the groups. The all-cause mortality rate during the follow-up period, was 5.5%, and amputation-free survival rates at 24 months were 97.0%, 90.6% and 90.9% in the DCB, DA, and BMS angioplasty groups, respectively. The primary patency rate for the DCB group (79.4%) exceeded those of the DA (56.2%) and BMS (52.2%) groups (p < 0.05), with no significant difference between the DA and BMS groups at 24 months. The secondary patency and clinically driven target lesion revascularization rates were similar among the three groups. A runoff number ≤1, Trans-Atlantic Intersociety Consensus (TASC) D, and severe calcification were found to be independent risk factors for primary patency. The DCB procedure demonstrated superior primary patency, compared to both BMS and DA procedures, in the treatment of femoropopliteal lesions.

The composition of the stent microbiome is associated with morbidity and adverse events during endoscopic drainage therapy of pancreatic necroses and pseudocysts.

Development of pancreatic necroses or pseudocysts are typical complications of pancreatitis and may require endoscopic drainage therapy using metal or plastic stents. Microbial infection of these lesions poses a major challenge. So far, the composition and significance of the microbial colonization on drainage stents are largely unknown although it may impact outcomes during endoscopic drainage therapy. A total of 26 stents used for drainage of pancreatic lesions were retrieved and the stent microbiome was determined by 16S rRNA gene sequencing. Additional analysis included comparison of the stent microbiome to the intracavitary necrosis microbiome as well as scanning electron microscopy (SEM) and micro-computed tomography (μCT) imaging of selected metal or plastic stents. The stent microbiome comprises a large proportion of opportunistic enteric pathogens such as Enterococcus (14.4%) or Escherichia (6.1%) as well as oral bacteria like Streptococcus (13.1%). Increased levels of opportunistic enteric pathogens were associated with a prolonged hospital stay (r = 0.77, p = 3e-06) and the occurrence of adverse events during drainage therapy (p = 0.011). Higher levels of oral bacteria were associated (r = -0.62, p = 8e-04) with shorter durations of inpatient treatment. SEM and μCT investigations revealed complex biofilm networks on the stent surface. The composition of the stent microbiome is associated with prolonged hospital stays and adverse events during endoscopic drainage therapy, highlighting the need for effective infection control to improve patient outcomes. In addition to systemic antibiotic therapy, antimicrobial stent coatings could be a conceivable option to influence the stent microbiome and possibly enhance control of the necrotic microflora.

Study on the complications after implantation of different types of metal stents in rabbit trachea

ObjectiveTo observe the complications and inflammatory responses caused by the different types of metal stents in the trachea of rabbits. Method79 rabbits were randomly divided into 4 groups and were implanted with the customized nickel-titanium alloy metal stents(fully covered metal stent: group A, bare metal stent: group B, segmented covered metal stent: group C and control group: group D). The complications (tracheal deformation, granulation tissue hyperplasia, scar hyperplasia and secretion retention) of different types of metal stents were compared by observing the anatomical and pathological specimens of dead rabbits; And the expression of inflammatory factors of different types of metal stents were compared by detecting the tissue of tracheas of dead rabbits. Results(1)There were significant differences in the above four complications among groups A, B and C(p < 0.01). The incidences of tracheal deformation, scar hyperplasia and secretion retention in group A were significantly higher than that in group B(p < 0.0167), however, the incidence of granulation tissue hyperplasia in group A was significantly lower than that in group B(p < 0.0167). The incidence of scar hyperplasia in group A was significantly lower than that in group C(p < 0.0167) and there were no significant differences in other complications between these two groups(p > 0.0167). The incidences of tracheal deformation, scar hyperplasia and secretion retention in group B were significantly lower than that in group C(p < 0.0167), however, the incidence of granulation tissue hyperplasia in group B was significantly higher than that in group C(p < 0.0167). (2)The concentration of IL-1β in group A was higher than that in group B (p < 0.05 and foldchange>1.2). Conclusion(1)There are significant differences in complications between the fully covered metal stent, bare metal stent and segmented covered metal stent; the incidences of complications between the segmented covered metal stent and fully covered metal stent are similar. (2)Changes in different inflammatory factors can be observed between the fully covered and bare metal stent.