Lung transplant airway complications treated with biodegradable airway stents: The Dutch multi-center experience.

INTRODUCTION: Treatment of post lung-transplant airway complications is challenging, and treatment with conventional airway stents is associated with adverse events. More recently, biodegradable airway stents (BDS) have been introduced and may be used to reduce these adverse events. In this study we explore the feasibility of treatment with BDS post lung transplant. METHODS: All patients treated with BDS in The Netherlands were included in this retrospective multicenter study. Feasibility, life span of the stent, occurrence of adverse events, and evolution of lung function were evaluated. RESULTS: Twelve patients (six malacia and six stenosis) received a total of 57 BDS, ranging from 1 to 10 BDS per patient. Six patients had been pretreated with conventional airway stents. Median stent life span was 112 days (range 66-202). No adverse events occurred during stent placement. In 5 out of 57 stent placements, a single additional bronchoscopy was necessary because of mucus accumulation (n = 4) or excessive granulation tissue (n = 1). All stent naïve patients became airway stent independent after treatment; all patients pretreated with conventional airway stents were still airway stent dependent at the end of follow up. CONCLUSION: Treatment with BDS is safe and feasible. Adverse events were mild and easily treatable. All patients with initial treatment with BDS were airway stent independent at the end of follow up with a median treatment of 4 BDS.

Three Decades Single Center Experience of Airway Complications After Lung Transplantation.

Post lung transplantation airway complications like necrosis, stenosis, malacia and dehiscence cause significant morbidity, and are most likely caused by post-operative hypo perfusion of the anastomosis. Treatment can be challenging, and airway stent placement can be necessary in severe cases. Risk factors for development of airway complications vary between studies. In this single center retrospective cohort study, all lung transplant recipients between November 1990 and September 2020 were analyzed and clinically relevant airway complications of the anastomosis or distal airways were identified and scored according to the ISHLT grading system. We studied potential risk factors for development of airway complications and evaluated the impact on survival. The treatment modalities were described. In 651 patients with 1,191 airway anastomoses, 63 patients developed 76 clinically relevant airway complications of the airway anastomoses or distal airways leading to an incidence of 6.4% of all anastomoses, mainly consisting of airway stenosis (67%). Development of airway complications significantly affects median survival in post lung transplant patients compared to patients without airway complication (101 months versus 136 months, p = 0.044). No significant risk factors for development of airway complication could be identified. Previously described risk factors could not be confirmed. Airway stents were required in 55% of the affected patients. Median survival is impaired by airway complications after lung transplantation. In our cohort, no significant risk factors for the development of airway complications could be identified.

Airway Stents from Now to the Future: A Narrative Review.

Airway stent insertion is important for patients with airway stenosis. Currently, the most widely used airway stents in clinical procedures are silicone and metallic stents, which offer patients effective treatment. However, these stents composed of permanent materials need to be removed, subjecting patients to invasive manipulation once more. As a result, there is a growing demand for biodegradable airway stents. Biodegradable materials for airway stents are now available in two types: biodegradable polymers and biodegradable alloys. Polymers that include poly (l-lactic acid), poly (D, l-lactide-co-glycolide), polycaprolactone, and polydioxanone are the ultimate metabolites which are generally carbon dioxide and water. Magnesium alloys are the most often utilized metal biodegradable materials for airway stents. The stent's mechanical properties and rate of degradation vary as a result of the different materials, cutting techniques, and structural configurations. We summarized the information above from recent studies on biodegradable airway stents conducted in both animals and humans. There is great potential for clinical applications for biodegradable airway stents. They avoid damage to the trachea during removal and reduce complications to some extent. However, several significant technical difficulties slow down the development of biodegradable airway stents. The efficacy and safety of different biodegradable airway stents still need to be investigated and proved.

A Prototype Implantable Artificial Bronchus Reduces Lung Hyperinflation in Recently Deceased Patients with Emphysema.

BACKGROUND: Several minimally invasive treatments have been offered to patients with severe emphysema over the last two decades. Currently, endobronchial valves (EBVs) are the only approved therapeutic option, but this method has drawbacks: only a few can undergo this therapy and the incidence of pneumothorax remains high. A minimally invasive technique, appropriate for a broader patient population and posing fewer risks, would represent a desirable alternative to improve lung function in these patients. OBJECTIVE: The objective of this study was to demonstrate whether a new prototype implantable artificial bronchus (IAB) releases trapped air from the lungs of recently deceased patients with emphysema. METHOD: Seven recently deceased patients with emphysema were mechanically ventilated and the respiratory rate increased from 12 bpm (resting) to 30 bpm (exercise), inducing air trapping and dynamic hyperinflation. This protocol was performed twice, before and after IAB placement. Ventilation parameters and the fraction of inspired oxygen were similar in all patients. Respiratory system plateau pressure (Pplat,rs) and intrinsic positive end-expiratory pressure (iPEEP) were measured. RESULTS: IAB implantation significantly reduced Pplat,rs (p = 0.017) in 6 of 7 deceased patients with emphysema and iPEEP (p = 0.03) in 5 of 7 patients. CONCLUSIONS: Placement of one or two IABs in segmental bronchi (up to 15th generation) proved to be feasible and improved lung function. These findings should provide a basis for subsequent clinical studies to assess the safety and efficacy of IAB in patients with emphysema, as well as identify short- and long-term effects of this innovative procedure.

Changes in Pulmonary Function Test Results and Respiratory Symptoms before and after Airway Stent Removal.

BACKGROUND: Airway stenting is a useful form of palliation for patients with airway stenosis/fistulas; the stent can be removed after addressing the cause of the airway disorder. Patients with airway stents often complain of coughing and difficulty with expectoration, so the use of such stents can negatively affect pulmonary function and worsen symptoms. OBJECTIVES: The aim of this study was to compare pulmonary function and respiratory symptoms before and after stent removal. METHODS: Patients who would later undergo simple airway stent removal were prospectively recruited in two institutions. All stents were removed using both rigid and flexible bronchoscopes with patients under general anesthesia. Pulmonary function tests were performed before stent removal and at 1 and 4 weeks after stent removal. All patients self-reported their respiratory symptoms using a 100-mm visual analog scale (VAS). RESULTS: Of the 31 patients enrolled, 28 (23 with malignant stenoses, 3 with benign stenoses, and 2 with fistulas [21 silicone and 7 metallic stents]) were included in analyses. Pulmonary function measurements before stent removal and at 1 and 4 weeks after stent removal were as follows: vital capacity, 3.00, 3.04, and 3.08 L (p = 0.387); forced expiratory volume in 1 s, 1.96, 1.96, and 2.12 L (p = 0.034); and peak expiratory flow, 3.60, 4.28, and 5.06 L/s, respectively (p < 0.001). Symptoms (cough, sputum production, difficulty with expectoration, and dyspnea) evaluated using the VAS improved significantly after stent removal. No complications were encountered during removal. CONCLUSION: Removal of unnecessary airway stents improves pulmonary function and respiratory symptoms. Any stent that is no longer functioning should be removed.

The Effectiveness of Nasal Airway Stent Therapy for the Treatment of Mild-to-Moderate Obstructive Sleep Apnea Syndrome.

BACKGROUND: Patients with obstructive sleep apnea syndrome (OSAS) experience excessive daytime sleepiness and insomnia and they are at risk of developing cardiovascular disease and stroke. Continuous positive airway pressure therapy could improve symptoms and decrease these risks; however, adherence is problematic. Although the oral appliance is another therapeutic option, patient satisfaction is limited and the effect of the nasal airway stent - a new device - remains unclear. OBJECTIVES: The aim of this study was to evaluate the effect of NAS therapy in patients with mild-to-moderate OSAS in a prospective, single-arm, interventional pilot study. METHOD: Patients with mild/moderate sleep apnea (n = 71; Apnea-Hypopnea Index [AHI], 5-20 events/h on polysomnography) were recruited. Sleep-associated events were measured using a portable device (WatchPAT200) pre- and immediately post-treatment and at 1 month follow-up. AHI (including supine and non-supine AHI), Oxygen Desaturation Index (ODI), Respiratory Disturbance Index (RDI), percutaneous oxygen saturation, heart rate, and snore volume were evaluated. Symptoms were assessed using the Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, and Hospital Anxiety and Depression Scale. RESULTS: NAS use significantly improved AHI, supine AHI, RD, ODI, and snore volume compared to pre-intervention (r = 0.44, 0.48, 0.3, 0.42, and 0.34; p < 0.001, p < 0.001, p = 0.011, p < 0.001, and p = 0.048, respectively). Additionally, 25 and 10% of patients showed complete and partial response for AHI, respectively; these improvements remained significant 1 month later. Pittsburgh Sleep Quality Index scores improved from 6.0 to 5.3 (r = 0.46, p = 0.022). CONCLUSIONS: NAS therapy reduced severity and snoring in patients with mild-to-moderate OSAS. Approximately 30% of patients did not tolerate NAS due to side effects.

Safety and Efficacy of the Tracheobronchial Bonastent: A Single-Center Case Series.

BACKGROUND: Tracheobronchial stents are widely used devices in interventional pulmonology; however, the current literature on the effectiveness and complication rates of the different types of stents is limited. OBJECTIVE: We report the largest case series of airway Bonastent placement and describe the efficacy and early (<30 days) and late (≥30 days) complication rates. METHODS: We performed a retrospective review of our prospectively collected database of patients who underwent therapeutic bronchoscopy with stent placement. All adult patients who had a tracheal/bronchial Bona-stent placed between July 1, 2017, and July 30, 2019, for any indication at our institution were included. The efficacy as well as intraoperative and short- and long-term complications of Bonastent placement were evaluated. RESULTS: Sixty Bonastents were placed in 50 patients. The etiology was malignant in 90% of the cases, while 2 patients had a tracheoesophageal fistula. All procedures were performed via rigid bronchoscopy. The most common location for stent placement was the bronchus intermedius, followed by the trachea, in 32 and 30% of the cases, respectively. Seventy percent of the patients (35/50) had improvement of respiratory symptoms within 30 days. Twenty-eight stents (48%) were removed at a mean of 74 days. Seventeen patients (34%) died within 30 days of stent placement. The overall complication rate was 54% (27/50 patients) at a mean follow-up of 111 days. The stent-related complication rate was 23.3% (14/60 cases) within <30 days and 53% (18/34 cases) at ≥30 days. CONCLUSIONS: The tracheobronchial Bonastent is effective for the treatment of patients with central airway obstruction and tracheoesophageal fistulae with an acceptable safety profile.

Utility of stent double palliation for esophageal cancer with airway involvement: the extremis of care.

Primary esophageal cancer (EC) frequently presents as a locally advanced disease with airway involvement. Placement of combined esophageal and airway stents has been reported in small series to be an effective palliation strategy. Our aims are to present the largest cohort of EC patients who underwent double stent palliation and to evaluate the safety and efficacy of this approach. Longitudinal cohort study of patients with primary EC undergoing two-stage esophageal and airway stent placement at an oncology referral institute (January 2000-January 2019). Assessments: baseline demographics and clinical variables; baseline and week 2 dysphagia, dyspnea and performance status (PS) scores; baseline and week 8 body mass index (BMI); overall survival. Statistics: paired t-test; Kaplan-Meier method. Seventy patients (89% men, mean age 60.20 ± 8.41) underwent double stenting. Esophageal stent was placed for esophageal stenosis and dysphagia (n = 41; placement of a second stent due to recurrence in nine cases) or esophagorespiratory fistulas (ERFs) (n = 29); airway stent was required for ERF sealing (n = 29 + 7 new ERFs after esophageal stent) and to ensure airway patency due to malignant stenosis (n = 29; placement of a second stent due to recurrence in 13 cases) or compression (n = 5). There were 13, endoscopically managed, major complications after esophageal stent [hemorrage (n = 1), migration (n = 5) and new fistulas (n = 7)]. As for airway stents, four major complications were recorded [hemorrage (n = 1) and three deaths due to respiratory infection and ultimately respiratory failure 3-7 days after the procedure]. Overall, patients showed significant improvement in dysphagia and dyspnea symptoms (3.21 vs. 1.31 e 15.56 vs. 10.87; P < 0.001). There was a PS improvement for 89.2% (n = 58) of the patients. BMI at week 8 was comparable to baseline records. Mean survival was 137.83 ± 24.14 days (95% CI: 90.51-185.15). Survival was longer for better PS (PS1, 249.95 days; PS2, 83.74 days; PS3, 22.43 days; PS4, 30.00 days). This is the largest comprehensive assessment of double stent palliation in advanced incurable EC. For both esophageal or airway stenosis and fistula, placement of combined esophageal and airway stents was a feasible, effective, fast-acting and safe modality for symptom palliation and body mass maintenance. Patient autonomy followed symptom improvement. Since it is impossible to provide treatment for cure in most of these cases, this endoscopic strategy, performed in differentiated units with the required technical capacity, may guarantee treatment for the relief of palliative EC.

Expiratory Central Airway Collapse in Adults: Corrective Treatment (Part 2).

Corrective treatment of expiratory central airway collapse (ECAC) consists of placement of airway stents or tracheobronchoplasty (TBP). The indication for corrective treatment is severe central airway collapse (>90 %), and severe symptoms that cause decline in quality of life. Patients are selected to undergo a trial of tracheal "Y" stent placement. If symptoms improve (positive trial) they undergo a TBP, provided they are good surgical candidates. Patients who are considered poor surgical candidates because of the severity of comorbidities can be offered permanent stenting to palliate symptoms. The anesthetic management of airway stent placement and TBP is complex. This article reviews the medical management and corrective treatment of ECAC, anesthetic management of airway stent placement, and considerations during TBP.

The utility of 3D-printed airway stents to improve treatment strategies for central airway obstructions.

Airway stents are commonly used in the management of patients suffering from central airway obstruction (CAO). CAO may occur directly from airway strictures, obstructing airway cancers, airway fistulas or tracheobronchomalacia, resulting from the weakening and dynamic collapse of the airway wall. Current airway stents are constructed from biocompatible medical-grade silicone or from a nickel-titanium (nitinol) alloy with fixed geometry. The stents are inserted via the mouth during a bronchoscopic procedure. Existing stents have many shortcomings including the development of obstructing granulation tissue in the weeks and months following placement, mucous build up within the stent, and cough. Furthermore, airway stents are expensive and, if improperly sized for a given airway, may be easily dislodged (stent migration). Currently, in Australia, it is estimated that approximately 12,000 patients will develop CAO annually, many of whom will require airway stenting intervention. Of all stenting procedures, the rate of failure is currently reported to be at 22%. With a growing incidence of lung cancer prevalence globally, the need for updating airway stent technology is now greater than ever and personalizing stents using 3D-printing technology may offer the best chance of addressing many of the current limitations in stent design. This review article will assess what represents the gold standard in stent manufacture with regards to treatment of tracheobronchial CAO, the challenges of current airway stents, and outlines the necessity and challenges of incorporating 3D-printing technology into personalizing airway stents today.

Metallic stent insertion and removal for post-tracheotomy and post-intubation tracheal stenosis.

PURPOSE: To study the safety and effectiveness of fluoroscopic insertion and removal of self-expandable metallic airway stent for post-tracheotomy tracheal stenosis (PTTS) and post-intubation tracheal stenosis (PITS). METHODS: We conducted a retrospective analysis of 32 patients who underwent fluoroscopic stenting from September 2011 to March 2017. The patients ranged in age from 12 to 69 years. Thirty-eight airway stents were implanted, 35 covered stents and three bare stents. Nineteen airway stents were used for 16 cases of PITS or PTTS. All patients underwent chest CT scans with/without bronchoscopy prior to stent removal. The indication of stent removal and post-interventional complications were analyzed. RESULTS: All 38 airway stents were successfully inserted. Insufficient expansion and tissue hyperplasia were most common complications after stenting. Thirty five of 38 airway stents were successfully removed fluoroscopically, with a technical success rate of 92.1%. Routine removal was performed after 2.9 ± 0.3 months, and stent restenosis was found after a mean duration of 2.7 ± 0.3 months. There were six complications of stent removal with no death. Four stents showed strut fracture after removal, of which three stent pieces retained. Two patients showed dyspnea immediately after removal and required mechanical ventilation in PTTS. One patient with PTTS lost of follow-up during a mean period of 33.7 ± 3.9 months. The one-, three- and five-year patency rates were 87.1%, 76.2% and 70.8%, respectively. There was no significant difference between PITS and PTTS. CONCLUSIONS: Fluoroscopic insertion and removal of airway stent is safe and effective for PITS and PTTS. A three-month retention time is reasonable for airway stents.

The efficacy of nasal airway stent (Nastent) on obstructive sleep apnoea and prediction of treatment outcomes.

BACKGROUND: Obstructive sleep apnoea (OSA) is characterised by recurrent episodes of partial or complete upper airway collapse during sleep and is highly prevalent in the general population. The nasopharyngeal airway stent (Nastent) is a specifically designed, preformed silicone tube that intends to maintain the upper airway patency during sleep and reduce snoring and sleep apnoea. OBJECTIVE(S): The purpose of this study was to determine the efficacy of Nastent treatment and examine predictors for Nastent treatment outcomes in patients with OSA. METHODS: Consecutive thirty patients were enrolled in this study. Cephalometric radiographs were obtained to analyse the pharyngeal and craniofacial morphology. Before and after Nastent treatment, we evaluated OSA using a portable sleep study. RESULTS: Twenty-nine subjects completed this study. There were significant decreases in the respiratory event index (REI) (22.4 ± 14.1 to 15.7 ± 10.4, P < 0.01) and a significant increase in the lowest SpO2 (81.9 ± 7.5 to 86.6 ± 4.8, P < 0.01) by Nastent treatment. Subjects were divided into responders and non-responders based on reduction in REI of >50% compared with baseline REI. We evaluated the ratio of inferior airway width and middle airway width (IAW/MAW) on cephalograms as the index of the narrowest airway site. The IAW/MAW was significantly higher in responders than in non-responders (1.4 ± 0.9 vs 0.9 ± 0.4, P < 0.01) and predicted treatment responders with high accuracy (sensitivity: 90.9%, specificity: 88.9%, when IAW/MAW was set at 1.10). CONCLUSIONS: The Nastent device improved OSA, and a narrower velopharynx than hypopharynx predicted treatment response with a good sensitivity and specificity.

External beam radiation therapy combined with airway stenting leads to better survival in patients with malignant airway obstruction.

BACKGROUND AND OBJECTIVE: Malignant airway obstruction (MAO), a common complication of patients with advanced lung cancer, causes debilitating dyspnoea and poor quality of life. Two common interventions used in the treatment of MAO include bronchoscopy with airway stenting and external beam radiotherapy (EBRT). Data are limited regarding their clinical effectiveness and overall effect on survival. METHODS: A retrospective chart review of patients treated with airway stenting and/or EBRT at the Johns Hopkins Hospital for MAO between July 2010 and January 2017 was reviewed. Demographics, performance status, cancer histology, therapeutic intervention and date of death were recorded. Survival was calculated using cox regression analysis. RESULTS: Of the 606 patients who were treated for MAO, 237 were identified as having MAO and included in the study. Sixty-eight patients underwent rigid bronchoscopy and stenting, 102 EBRT and 67 a combined approach. Patients who underwent stenting hand an increased hazard ratio (HR) of death in comparison to those who received combination therapy (HR: 2.12, 95% CI: 1.02, 4.39), while there was a trend towards significance in the EBRT alone group in comparison to the combination therapy group (HR: 1.62, 95% CI: 0.93, 2.83). CONCLUSION: In this retrospective analysis, combination therapy with stenting and EBRT led to better survival in comparison to stenting or EBRT alone. Prospective cohort trials are needed to confirm these results.

Application of 3D Printing for Patient-Specific Silicone Stents: 1-Year Follow-Up on 2 Patients.

Managing complex benign airway disease is a major challenge in interventional pulmonology. Airway stent placement can result in complications due to a variety of factors, including poor fit of the stent in the airway. We report the 1-year outcome of 2 patients with airway disease caused by granulomatosis with polyangiitis (Wegener's) affecting the left main bronchus and secondary carina. These patients had not responded to systemic therapy or standard bronchoscopic techniques and had complications with commercially available airway stents. We describe a first-in-human, clinical experience to address these issues. Using computed tomography (CT) imaging and 3D printing technology, we generated and implanted patient-specific silicone airway stents to address airway disease. 3D patient-specific stent prescription was created using a CT scan of the patient's chest and a proprietary software package originally developed for orthopedic surgical planning. Silicone stents were manufactured and implanted. Observation for > 1 year after implantation compared to the 6 months prior to patient-specific stent implant were compared for the number, clinically required stent changes, procedure time, and general clinical improvement per usual standard of care after airway stenting. Patients showed improved durability, a shorter procedure time, and improvement of patient-reported symptoms leading to a reduced need for stent changes and modifications. The use of 3D printing technology to make patient-specific silicone stents is feasible with early clinical proof of concept noting a durable improvement over 1 year of follow-up.

Endobronchial stenting on VV-ECMO in a 6-month-old girl with right lung agenesis and severe stenosis of the left main bronchus.

INTRODUCTION: Lung agenesis is a rare disorder with a variable, but potentially very bad clinical course. It necessitates complex clinical management, especially in life-threatening situations. CASE REPORT: We describe a case of a 6-month-old girl with right lung agenesis who required venovenous extracorporeal membrane oxygenation (VV-ECMO) due to pneumonia complicated by exacerbated previously diagnosed left main bronchus stenosis. The stenosis was resolved by endobronchial intervention and X-ray-guided stent insertion, which enabled weaning from ECMO and was aimed at preventing such a life-threatening respiratory failure in the future. Unfortunately, even with the functional stent, the baby died 2 months post-procedure due to unresolvable bronchial spasms. DISCUSSION: Despite high endobronchial stenting-related mortality in children, in cases where no effective pharmacological or surgical alternatives exist, stenting may be safely performed during VV-ECMO support and be a viable option to overcome critical respiratory failure caused by bronchial stenosis.

Clinical significance of differentiating post-intubation and post-tracheostomy tracheal stenosis.

BACKGROUND AND OBJECTIVE: Post-intubation tracheal stenosis (PITS) and post-tracheostomy tracheal stenosis (PTTS) are serious complications in mechanically ventilated patients. Although the aetiologies and mechanisms of PITS and PTTS are quite different, little is known about the clinical impact of differentiating one from the other. METHODS: We retrospectively conducted a chart review of 117 patients with PITS and 88 patients with PTTS who were treated with interventional bronchoscopy at Samsung Medical Center between January 2004 and December 2013. RESULTS: Compared to patients with PITS, patients with PTTS had a lower BMI, poorer performance status and more frequent neurological aetiologies, mid-to-lower tracheal lesions, total obstruction and mixed stenosis types. Although there were no differences in the number of patients who received silicone stents between the two groups, Montgomery T-tubes were more frequently used in the PTTS group than in the PITS group. The final success rate without surgery, mortality or tracheostomy in situ was higher in the PITS group than in the PTTS group (76.9% vs 63.6%, P = 0.043). Additionally, airway prosthesis removal was achieved in 46.2% of patients in the PITS group and in 33.0% of the PTTS group (P = 0.063). CONCLUSION: There were significant differences between PITS and PTTS in terms of patient and stenosis characteristics, treatment modalities and clinical outcomes. Therefore, PITS and PTTS should be considered two different entities.

Graphene oxide-loaded rapamycin coating on airway stents inhibits stent-related granulation tissue hyperplasia.

OBJECTIVES: Our objective was to explore the safety and efficacy of a graphene oxide-loaded rapamycin-coated self-expandable metallic airway stent (GO@RAPA-SEMS) in a rabbit model. METHODS: The dip coating method was used to develop a GO@RAPA-SEMS and a poly(lactic-co-glycolic)-acid loaded rapamycin-coated self-expandable metallic airway stent (PLGA@RAPA-SEMS). The surface structure was evaluated using a scanning electronic microscope. The in vitro drug-release profiles of the 2 stents were explored and compared. In the animal study, a total of 45 rabbits were randomly divided into 3 groups and underwent 3 kinds of stent placements. Computed tomography was performed to evaluate the degree of stenosis at 1, 2 and 3 months after the stent operation. Five rabbits in each group were sacrificed after the computed tomography scan. The stented trachea and blood were collected for further pathological analysis and laboratory testing. RESULTS: The in vitro drug-release study revealed that GO@RAPA-SEMS exhibited a sudden release on the first day and maintained a certain release rate on the 14th day. The PLGA@RAPA-SEMS exhibited a longer sustained release time. All 45 rabbits underwent successful stent placement. Pathological results indicated that the granulation tissue thickness in the GO@RAPA-SEMS group was less than that in the PLGA@RAPA-SEMS group. The TUNEL and hypoxia-inducible factor-1α staining results support the fact that the granulation inhibition effect in the GO@RAPA-SEMS group was greater than that in the PLGA@RAPA-SEMS group. CONCLUSIONS: GO@RAPA-SEMS effectively inhibited stent-related granulation tissue hyperplasia.

Efficacy of airway stenting and nasogastric tube insertion in airway-esophageal fistula patients with airways compromised by advanced malignancy.

INTRODUCTION: Whether airway-compromised airway-esophageal fistula (AEF) patients should undergo combined airway and esophageal stenting is controversial. This study was designed to evaluate the survival prognosis and poststent interventions in AEF patients with airways compromised by advanced malignancy with or without airway stents. METHODS: A retrospective analysis of the medical records, survival times, and poststent interventions of 17 patients with or without airway stents was performed. RESULTS: The causes of AEF were esophageal cancer (11/17, 64.7%), lung cancer (6/17, 29.4%), and thyroid cancer (1/17, 5.9%). All patients received a nasogastric tube (n = 12) or underwent gastrostomy (n = 5) to resume enteral nutrition. Thirteen patients underwent airway stent insertion (13/17, 76.5%), whereas four patients did not. Four patients with a high risk of stent migration received external stent fixation to the trachea. Three of the patients with stents suffered severe granulation tissue formation and needed repeated bronchoscopy interventions. In the stented group, none of the patients developed stent migration, and the overall median survival time was 9 months, compared with 1.25 months in the nonstented group (P = 0.04). Cox proportional hazards regression revealed that stent insertion, nasogastric tube insertion, and transcatheter bronchial artery chemoembolization were protective factors against death, whereas surgery-related fistula, fistula larger than 2 cm, continued chemotherapy, and age were risk factors for poor survival (P < 0.05). CONCLUSION: In airway-compromised AEF patients, airway stents and nasogastric tubes are probably the preferred treatments. Airway stenting is tolerable, and routine weekly poststent bronchoscopy is needed in the first month and depending on respiratory symptoms thereafter.

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

OBJECTIVE: To observe the complications and inflammatory responses caused by the different types of metal stents in the trachea of rabbits. METHOD: 79 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-1ß 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.