Airway Stent Implantation Research Articles

Clinical Study of Airway Stent Implantation in the Treatment of Patients with Malignant Central Airway Obstruction.

Background Airway stenting is a therapeutic option for malignant central airway obstructions (MCAO), including both intraluminal and extraluminal obstructions. The objective of this study is to investigate the clinical features and results of long-term improved prognosis for MCAO patients after airway stent implantation. Methods Ninety-eight MCAO patients who underwent stent placement in our hospital from January 2013 to April 2020 were included in this study. The data included baseline data, clinical characteristics, laboratory test data, stent implantation data, and treatment as well as survival after stent implantation. The survival rates among individuals were compared via log-rank tests. Potential prognostic factors were identified using multivariate cox hazard regression models. Results A retrospective analysis of these patients was generated. MCAO was mainly caused by lung cancer (53/98, 54.08%), esophageal cancer (22/98, 22.45%), and thyroid cancer (3/98, 3.06%). The median survival time of participants was 5.5 months. Univariate analysis indicated that the survival rate was related to primary disease, ECOG PS score, stent site, hemoglobin (Hb), albumin (ALB), and serum lactate dehydrogenase (LDH) (P < 0.05). The cox risk regression model showed that the survival rate was significantly influenced by ECOG PS score (OR = 3.468, 95%CI = 1.426–8.432, P = 0.006) and stent site (OR = 1.544, 95%CI = 1.057–2.255, P = 0.025). Conclusions Compared with the site of stent placement, the ECOG PS score is the primary factor in the survival rate of MCAO patients after airway stenting.

Comparison of operation time, efficacy and safety between through-the-scope stent and over-the-while stent in malignant central airway obstruction: a multi-center randomized control trial.

BackgroundSelf-expandable metallic (SEM) airway stents are an important approach to treating malignant central airway obstruction (CAO). Standard over-the-while (OTW) stent needs the guidance of a guide-wire. It should be implanted under flouroscopy or the guidance of bronchoscope visualization. In this study, we evaluated the operation time and safety between OTW stent and a novel through-the-scope (TTS) SEM airway stent.MethodsIn this multi-center, randomized, parallel-group superiority study, malignant CAO patients were enrolled randomly assigned (2:1) to the TTS stent implantation group (TTS group) or the standard OTW stent group (OTW group) in six sites across China. The entire process of all surgical procedures was recorded by video. Primary endpoint was the operation time of the airway stent implantation and secondary endpoint was the success rate of the stent implantation as well as its efficacy and safety.ResultsFrom May 15, 2017, to December 30, 2018, 148 patients were enrolled from the six sites. We analyzed 134 patients (including 91 patients from the TTS group and 43 patients from the OTW group) according to the per-protocol set. There were no significant differences in the ages, genders, underlying diseases, and stenosis sites between the two groups. The operation time in the TTS group was significantly shorter than that in the OTW group (104±68 vs. 252±111 seconds, P<0.001). Compared to the OTW group, the efficacy of stent implantation (97.80% vs. 90.70%, P=0.093) and rate of first-time successful stent implantation (78.02% vs. 74.42%, P=0.668) were higher in the TTS group, but did not reach statistically significance. The rates of granulation (28.57% vs. 41.86%, P=0.128) and restenosis (15.38% vs. 30.23%, P=0.064) in the TTS group were slightly lower as compared with the OTW group without achieving statistical significance.ConclusionsThe TTS stent implantation procedure time was significantly shorter than that of the OTW airway stent with similar efficacy and complications, which might reduce the risk and flexibility of stent implantation.Trial RegistrationChinese Clinical Trial Registry ChiCTR-IOR-17011431.

Sequential treatment of severe airway stenosis caused by esophageal cancer by using airway stent implantation and arterial infusion chemotherapy

The purpose of this clinical study was to investigate the efficacy and safety of airway stent implantation and transarterial infusion chemotherapy in the sequential treatment of severe airway stenosis caused by esophageal cancer. Data of patients with advanced esophageal cancer complicated by severe airway stenosis treated with airway stent implantation and transarterial infusion chemotherapy were retrospectively analyzed. Furthermore, dyspnea, clinical efficacy, adverse reactions, and survival of patients were evaluated. 71 patients were included in this study. There were 28 patients with grade III dyspnea and 43 patients with grade IV dyspnea before airway stent implantation, and 34 patients with grade I dyspnea, 35 patients with grade II dyspnea and 2 patients with grade III dyspnea after airway stent implantation. After airway stent implantation and 1–3 courses of transarterial infusion chemotherapy, 11, 41 and 19 patients had complete response, partial response and stable response respectively. Total disease control rate (DCR) and objective response rate (ORR) were 100.0% and 73.2%, respectively. During the follow-up, 32 patients died of organ failure, 24 patients died of tumor-related respiratory failure, and 10 patients died of gastrointestinal bleeding. The median survival time of all patients was 8 months, and the 1-year survival rate was 40.8%. Airway stent implantation combined with arterial infusion chemotherapy is safe and effective for sequential treatment of esophageal cancer with severe airway stenosis.

Paclitaxel-Loaded PLGA Coating Stents in the Treatment of Benign Cicatrical Airway Stenosis

Background: Airway stent implantation used in the treatment of benign cicatricial airway stenosis (BCAS) can lead to local granulation and scar formation, resulting in restenosis and treatment failure. Methods: We systematically investigated a paclitaxel-loaded PLGA-coating stent (PLPCS) and analyzed the safety and efficacy of the PLPCS in patients with BCAS. Patients were enrolled from four hospitals in China and observed for six months after implantation, by bronchoscopy performed weekly in the first month and monthly thereafter. The stent was removed immediately upon detection of granulation tissue proliferation, leading to immobility of the stent. Results: Granulation tissue was formed one week after stent implantation, most of which was located at the upper edge of the stent and the narrowest airway in the stent. All stents were removed in three months (mean: 6.51 + 4.67 weeks), with a curative outcome in one case and ineffective results in two. The remaining seven patients developed complications within three months, necessitating early stent removal. The main complication was granulation formation, resulting in difficulty in stent removal. Conclusion: Although PLPCS showed beneficial effects in basic and animal experiments, it cannot prevent airway restenosis in actual practice, mainly due to granulation formation.

Bronchoscopy-Guided Intervention Therapy With Extracorporeal Membrane Oxygenation Support for Relapsing Polychondritis With Severe Tracheobronchomalacia: A Case Report and Literature Review

Relapsing polychondritis is an immune disorder of unknown etiology involving multiple systems that is characterized by persistent inflammation and destruction of cartilage, including the ears, nose, costal, joint, and airways. Airway involvement caused by relapsing polychondritis is common, and tracheobronchomalacia is the most serious complication, which is life-threatening. Currently, the exact mechanism of relapsing polychondritis with tracheobronchomalacia is unknown. Although glucocorticoids and immunosuppressive agents are administered, failures often occur. Currently, bronchoscopy-guided intervention therapy used in tracheobronchomalacia caused by chronic obstructive pulmonary disease or other etiology has gradually increased, but bronchoscopy-guided intervention therapy with extracorporeal membrane oxygenation assist used in tracheobronchomalacia caused by relapsing polychondritis has not been reported. Here, we report a case of relapsing polychondritis with severe tracheobronchomalacia. Although drug therapy was provided and airway stent implantation was performed, the tracheal stenosis was further aggravated. Because conventional anesthesia and mechanical ventilation cannot meet the needs of bronchoscopy-guided intervention therapy or guarantee sufficient safety. The intervention treatment was performed with the support of extracorporeal membrane oxygenation, which was successfully completed without obvious complications. The symptoms were significantly improved, and the patient was discharged uneventfully.

Design and manufacturing workflow of a patient specific 3-dimensionally engineered tracheo-bronchial stent

Collapsing airway pathologies, such as vanishing bronchus syndrome, are routinely treated by airway stent implantation. Off-the-shelf stents are appropriate for the treatment of most patients. However, in some cases, these commercially available stents do not fit the patient's airway anatomy sufficient, resulting in a high risk for dislocation and infection. In this article, we present a process for design and manufacturing of patient-specific tracheobronchial stents that allows treatment of patients in whom standard treatment is not appropriate.

Using individualized three-dimensional printed airway models to guide airway stent implantation

Airway stents are used to manage central airway obstructions by restoring airway patency. Current manufactured stents are limited in shape and size, which pose issues in stent fenestrations needed to be manually created to allow collateral ventilation to airway branches. The precise location to place these fenestrations can be difficult to predict based on 2-dimensional computed tomography images. Inspiratory computed tomography scans were obtained from 3 patients and analysed using 3D-Slicer™, Blender™ and AutoDesk® Meshmixer™ programmes to obtain working 3D-airway models, which were 3D printed. Stent customizations were made based on 3D-model dimensions, and fenestrations into the stent were cut. The modified stents were then inserted as per usual technique. Two patients reported improved airway performance; however, stents were later removed due to symptoms related to in-stent sputum retention. In a third patient, the stent was removed a few weeks later due to the persistence of fistula leakage. The use of a 3D-printed personalized airway model allowed for more precise stent customization, optimizing stent fit and allowing for cross-ventilation of branching airways. We determine that an airway model is a beneficial tool for stent optimization but does not prevent the development of some stent-related complications such as airway secretions.

Follow-Up Investigation of 41 Children After Metallic Airway Stent Implantation: An 8-Year Experience.

Objective: To present 8-year follow-up outcomes, treatment of complications, and prognosis in children with congenital tracheal stenosis after metallic airway stent implantation.Methods: Retrospective analysis was performed on the clinical records of children who had airway stents placed between May 20, 2011 and May 31, 2016, and on their follow-up records collected on November 31, 2019.Results: During the 8 years follow-up, 41 children underwent airway stenting under flexible bronchoscopy and participated in the follow-up investigation. There were 26 cases with left main bronchus (LMB) stenosis (63.4%), 16 cases with congenital tracheal stenosis (CTS, 39.0%), 12 cases with right main bronchus (RMB) stenosis (29.3%), and 1 case of subglottic stenosis (2.4%). A total of 76 stents were implanted, and 21 patients died after implantation. There were 34 children (82.9%) with congenital heart disease (CHD), while other diseases accounted for <5%. Among children with CHD and those with other conditions, the number of death cases was 19 and 2, respectively; no significant differences were observed between the two groups (P>0.05). The most frequent complications were increased airway secretion (75.8%), stent deformation (66.7%), and granulation tissue hyperplasia (60.6%). The airway stenosis (45.5%) and stent migration (12.1%) occurred at a moderate rate. The less common complications were airway softening (6.1%), and stent breakage (6.1%).Conclusions: The placement and removal of the metallic stent are convenient and quick procedures that can relieve the symptoms of dyspnea caused by airway stenosis in the case of an emergency. After stent implantation, the primary disease should be actively treated, and the stent should be removed as soon as possible after the cause of airway stenosis is successfully removed. Larger stents are more likely to cause complications; thus, a good follow-up system should be established to timely address all the complications.

Comparison of etiology and incidence of pulmonary infection in patients with esophageal carcinoma accompanied by esophagotracheal fistula before and after the airway stent implantation

Objective: To compare the etiology and incidence of pulmonary infection in patients with esophageal carcinoma accompanied by esophagotracheal fistula before and after the airway stent implantation. Methods: The clinical records of patients with esophageal carcinoma accompanied by esophagotracheal fistula in Respiratory Department and Oncology Department of Meitan General Hospital were retrospectively analyzed from March 2008 to January 2018. The demographic data, comorbidities, pathological results and etiology were collected before and after tracheal stents were implanted in all patients. The incidence of pulmonary infection was analyzed, and the classification of etiology was compared before and after tracheal stents implantation. Results: A total of 100 patients were included in the study. The incidence rate of pulmonary infection before stents implantation was 83.0%. A total of 105 bacterial strains were cultured, including 73 strains of gram-negative bacteria (69.5%) and mainly pseudomonas aeruginosa, 5 strains of gram-positive bacteria [all methicillin-resistant staphylococcus aureus (MRSA)] (4.8%), and 27 strains of fungi (25.7%) and mainly candida albicans. The incidence rate of pulmonary infection was lowered to 53.0% after tracheal stents implantation (χ(2)=29.102, P<0.001). A total of 79 bacterial strains were cultured, and the main bacteria were still gram-negative bacteria and fungi, in which pseudomonas aeruginosa and candida albicans accounted for the majority. However, 13 strains of MRSA were cultured (16.5%), significantly higher than those before stents implantation (χ(2)=7.451, P=0.005). Conclusions: The incidence rate of pulmonary infection in patients with esophageal carcinoma accompanied by esophagotracheal fistula is very high. Gram-negative bacteria and fungi are the main etiologies. Tracheal stents implantation can effectively reduce the incidence of pulmonary infection. However, the incidence rate of MRSA is significantly increased after stents implantation.

Magnetic resonance imaging of patients with airway stents.

Airway stent implantation is a highly effective treatment for airway stenosis. However, it is presently unclear whether patients with airway stents can safely undergo magnetic resonance imaging (MRI). Such stents may be metallic or non-metallic, and MRI may induce stent dislodgment or heating and may be associated with stent-induced artifacts. We thoroughly reviewed the literature, experimental data, and manufacturer information on non-metallic, stainless steel (SS) and nickel-titanium alloy stents. Non-metallic stents are made of non-ferromagnetic materials associated with no MRI concerns. SS stents may shift in a magnetic field, generating significant artifacts. Nickel-titanium alloy stents are not at risk of dislodgement or heating, but may create some artifacts affecting image quality. Both non-metallic and nickel-titanium alloy stents are safe for patients who must undergo MRI. However, the safety of SS stents depends on the type of steel used.

Airway Stents Implantation with Extra Pulmonary or Intrapulmonary Oxygen Support on Respiratory Failure Patients

Severe airway stenosis may result in respiratory failure. Airway stent implantation has been used to relieve the symptoms of airway stenosis. During stent implantation, how to provide oxygen support is more important. Up to now, there are two oxygen support methods including extrapulmonary oxygen support and intrapulmonary oxygen support. The former method involves percutaneous cardiopulmonary support (PCPS) and extracorporeal membrane oxygenation (ECMO). In this way, stent implantation is more convenient because airway is not occupied by intubation tube. Furthermore, PCPS and ECMO can provide not only pulmonary but also cardiac support, which is advantageous for those patients who suffer from severe airway stenosis and cardiovascular diseases. The intrapulmonary oxygen support methods include rigid bronchoscopy and tracheal intubation attached mechanical ventilation. Rigid bronchoscopy can be used to implant silicon and metallic stents. On intubated patients, more pulmonologists have performed stent insertion via fluoroscopy with/without flexible bronchoscopy. For avoiding X-ray exposure, flexible bronchoscope passing outside endotracheal tube or ultrathin bronchoscope have been ingeniously developed to implant airway stents.

Individualized airway-covered stent implantation therapy for thoracogastric airway fistula after esophagectomy.

Thoracogastric airway fistula (TGAF) is a rare and dangerous complication of esophagectomy performed for esophageal and cardiac carcinomas. Herein, we aimed to explore the feasibility and efficacy of individualized airway stent implantation for the treatment of TGAF after esophagectomy. Based on different TGAF types and relevant data on chest computed tomography, customized airway-covered stents were positioned so as to cover the entrance to the fistula by an interventional radiologist using fluoroscopic guidance. Of the 63 patients with TGAF, 12 had thoracogastric-tracheal fistulas, 14 had thoracogastric-carinal fistulas, 21 had thoracogastric-left main bronchial fistulas, 15 had thoracogastric-right main bronchial fistulas, and 1 had a thoracogastric-right intermediate bronchial fistula. The following different stent types were placed: 7 straight self-expandable covered metallic stents, 2 hinged self-expandable covered metallic stents, 41 Y-shaped self-expandable covered metallic stents, and 13 large Y and small Y paired self-expandable covered metallic stents. In all 59 cases (93.65%), the implantation was successful at the first attempt, with the procedure times ranging from 5 to 10min. Esophagograms with water-soluble iodinated contrast showed that the fistulae were completely covered with no contrast flowing into the airways and lungs, and with the stents fully expanded. We recorded four cases (6.35%) of incomplete or recurrent fistula closure. Customized airway-covered stents may be an appropriate palliative therapy for patients with thoracogastric airway fistula who are unfit for surgery or have a high postoperative risk.

Study of Pre- and Post-Stent Implantation in the Trachea Using Computational Fluid Dynamics

Computational fluid dynamics (CFD) allows the visualization and understanding of physics of flow associated with stent implantation. This study uses patient computed tomography (CT) images to investigate the relationship of pressure drop and air flow rate in the tracheal airway. Moreover, the cross-sectional areas of the patient airway were measured and the area stenosis ratios were calculated. The stenosis ratios were 75.64% and 38.08% without and with stent treatment, respectively. Simulation results show that at an air flow rate of 30 L/min, the pressure drops between the inlet and the outlet before and after central airway stent implantation for the inspiratory phase were 77.23 and 7.05 Pa, respectively. The improvement gain (IG) was 9.95. The IG increased with increasing air flow rate. At an air flow rate of 120 L/min, the value of IG was 11.68. A higher IG value indicates lower airway resistance after an airway stent implantation. The CFD numerical results demonstrate the feasibility of computing airway resistance based on CT images. In clinical practice, it is difficult to assess patients with severe airway obstruction using a symptoms score or a pulmonary function test due to their critical condition. The proposed noninvasive approach for determining airway obstruction severity is helpful for patients who are unable to do pulmonary function tests.