Long-term tolerance of airway silicone stent in patients with post-tuberculosis tracheobronchial stenosis

Clinical Factors for Successful Removal of Airway Silicone Stents in Patients With Post-Tuberculosis Tracheobronchial Stenosis

BACKGROUND

After relieving stenosis with an airway silicone stent in post-tuberculosis bronchial stenosis (PTTS), stent removal is attempted if it is determined that airway patency can be maintained even after stent removal. However, the factors affecting airway stent removal are not well known. We investigate the factors that enable the successful removal of airway silicone stents in patients with PTTS.

METHODS

We retrospectively analyzed PTTS patients who underwent bronchoscopic intervention from January 2004 to December 2019. Successful stent removal is defined as airway patency maintained when the stent is removed, so that reinsertion of the stent is not required. A multivariate logistic regression analysis was used to identify independent factors associated with successful stent removal at the first attempt.

RESULTS

Total 344 patients were analyzed. Patients were followed up for a median of 47.9 (26.9-85.2) months after airway stent insertion. Approximately 69% of PTTS patients finally maintained airway patency after the stent was removed. Factors related to successful stent removal at the first attempt were older age and male sex. Absence of parenchymal calcification, segmental consolidation & bronchiolitis, and no trachea involved lesion were relevant to the successful stent removal. Stent dwelling for 12-24 months was associated with successful stent removal compared to a duration of less than 12 months.

CONCLUSION

For patients whose airway patency is determined to be maintained even without a stent, it is necessary to attempt stent removal in consideration of factors related to successful stent removal.

Rigid Bronchoscopy for Post-tuberculosis Tracheobronchial Stenosis

The healing process of tracheobronchial tuberculosis (TB) results in tracheobronchial fibrosis causing airway stenosis in 11% to 42% of patients. In Korea, where pulmonary TB is still prevalent, post-TB tracheobronchial stenosis (PTTS) is one of the main causes of benign airway stenosis causing progressive dyspnea, hypoxemia, and often life-threatening respiratory insufficiency. The development of rigid bronchoscopy replaced surgical management 30 years ago, and nowadays PTTS is mainly managed by bronchoscopic intervention in Korea. Similar to pulmonary TB, tracheobronchial TB is treated with combination of anti-TB medications. The indication of rigid bronchoscopy is more than American Thoracic Society (ATS) grade 3 dyspnea in PTTS patients. First, the narrowed airway is dilated by multiple techniques including ballooning, laser resection, and bougienation under general anesthesia. Then, most of the patients need silicone stenting to maintain the patency of dilated airway; 1.5 to 2 years after indwelling, the stent could be removed, this has shown a 70% success rate. Acute complications without mortality develop in less than 10% of patients. Subgroup analysis showed successful removal of the stent was significantly associated with male sex, young age, good baseline lung function and absence of complete one lobe collapse. In conclusion, rigid bronchoscopy could be applied to PTTS patients with acceptable efficacy and tolerable safety.

Post-tuberculosis tracheobronchial stenosis: long-term follow-up after self-expandable metallic stents placement and development of a prediction score-the Restenosis Score

Background

The insertion of self-expandable metallic stents (SEMS) for post-tuberculosis tracheobronchial stenosis (PTTS) was controversial. This study aimed to evaluate the efficacy and safety of SEMS for treating PTTS, and developed a scoring system for predicting the occurrence of restenosis after stenting in PTTS patients.

Methods

We conducted a retrospective review of 87 patients who were diagnosed with PTTS and experienced SEMS insertion between January 2000 and December 2017. All procedures were performed via flexible bronchoscopy under conscious sedation and local anesthesia.

Results

A total of 85 SEMS were successfully placed in 77 patients. Comparing with pre-stenting, there were significant improvements in the lumen diameters of the stenotic segment, mMRC scale and lung function after short-term SEMS placement. During the long-term (average 163.32 months) follow-up, 48 patients (62.3%) did not develop restenosis after stenting; the other 29 patients (37.7%) developed and eventually, 12 remained under interventional therapies and 11 had bronchial atresia. Multivariate Cox regression analysis revealed that the difference value between SEMS length and the stenosis-segment length, stenosis type, and the number of pre-stenting thermal ablation were independently related to restenosis occurrence and were subsequently used to establish the Restenosis Score. The model’s development group (0.83, 95% CI 0.74–0.92) and external validation set (0.94, 95% CI 0.77–1.00) showed excellent discrimination.

Conclusion

SEMS placement could serve as a safe and effective treatment option for most patients with PTTS. Further, we built a prediction model depending on the independent predictors of restenosis occurrence, the Restenosis Score. This validated tool might provide a decision support and a better management for PTTS patients who underwent SEMS implantation.

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.

Low-activity 125I implantation into VX2 tumor rabbits and quantitative evaluation of the precise therapeutic effect

There is still controversy about quantitatively evaluating the therapeutic effect of radioactive low-activity iodine-125 seeds (¹²⁵I seeds). In the present study, a paired VX₂ tumor model in a rabbit hind leg muscle was established, which is virus-induced anaplastic squamous cell carcinoma characterized by hypervascularity, rapid growth and easy propagation in the skeletal muscle. ¹²⁵I seeds with 0.4 and 0.7 mCi activity were implanted into the left and right legs, respectively, using a radiation treatment planning system under positron emission tomography (PET)/computed tomography (CT) guidance. PET/CT scans and hematoxylin and eosin staining were observed at 72 h and 2 and 4 weeks after implantation to assess the therapeutic effect. The results showed that the average tumor length and standard uptake value (SUV) decreased over time, and both ¹²⁵I seed groups achieved therapeutic effects at 4 weeks post-implantation. Quantitative evaluation of tumor inhibition rate, SUV variation and tumor marker ratio (Bcl-2/Bax) suggested that 0.7 mCi ¹²⁵I seeds were more suitable than 0.4 mCi seeds in a clinical setting.

Self-expanding covered metallic stents as a transition to silicone stent implantation in management of severe post-tuberculosis bronchial stenosis

BACKGROUND AND AIMS

Post-tuberculosis bronchial stenosis (PTBS) is one of the most common complications of tracheobronchial tuberculosis. Silicone stent serves as a major treatment for maintaining airway patency. However, silicone stent placement remains a large challenge in patients with severe cicatricial PTBS. Our objective was to evaluate the efficacy and safety of covered, self-expanding, metallic stents (SEMSs) as a transition to silicone stent implantation for treating severe PTBS.

METHODS

We retrospectively reviewed the data of patients with severe PTBS who received airway stenting in the First Affiliated Hospital of Guangdong Medical University between September 2015 and May 2019. The types of the stent, intervention procedures, bronchoscopic findings, clinical outcomes and related complications were collected and analyzed.

RESULTS

Fifty-eight cases with severe PTBS were included in this study. Thirteen (22.4%) of the patients received bronchial silicone stent implantation immediately after dilations. For the remaining 45 (77.6%) patients, silicone stents could not be deployed after dilations and SEMSs implantation was implemented as a bridge to silicone stenting. The SEMSs were placed for an interval of 28.4 ± 11.1 days. All of the silicone stents were inserted successfully following the removal of SEMSs. No SEMS-related complication occurred. The subgroup analysis showed that patients who received transitional SEMSs had less luminal caliber but fewer transbronchial dilations before silicone stent implantation (p < 0.05).

CONCLUSION

Covered SEMS placement as a transition to silicone stenting could serve as a feasible procedure to reduce complications and improve the success rate of silicone stent implantation in patients with severe PTBS.The reviews of this paper are available via the supplemental material section.

A novel designed V-shaped silicone stent for the treatment of unilateral main bronchial stenosis V-shaped stent for bronchial stenosis

Benign main bronchial stenosis may cause a potentially life-threatening condition. Airway silicone stenting is an important option of bronchoscopic treatments for patients with main bronchial stenosis. However, stent migration is one of the most frequent complications, which require repeated bronchoscopic interventions. To resolve this issue, we therefore in the report described a novel designed V-shaped silicone stent for the treatment of unilateral main bronchial stenosis. This method may be widely applied to clinical practice to prevent stent migration.

Angulated Stents-A Novel Stent Improvisation to Manage Difficult Post-tuberculosis Bronchial Stenosis

Post-tuberculosis bronchostenosis (PTBS), a complication of endobronchial tuberculosis is currently treated by bronchial stenting. However, in cases of angulated bronchial stenoses, difficulty is often encountered in stent insertion and maintenance, resulting in stent migration, granulation tissue overgrowth, and restenosis. To accommodate the angulated alignment of the stenosis, we devised an "angulated stent"-a novel improvisation of the conventional stent via splicing and suturing to achieve a resultant angulated shape. A retrospective review was undertaken to evaluate the performance of this stent. Among 283 PTBS patients who underwent interventional bronchoscopy at our center from 2004 to 2014, 21 were treated with at least one angulated stent. Clinical outcomes, including the stenting duration were investigated. After a median follow-up of 26 months, stent removal was successful in 7 (33.3%) out of 21 patients. In patients managed with angulated stents, the median duration to stent change or eventual removal was longer than those treated with straight tube stents (392 days vs. 86 days; p < 0.05). Angulated stents are a feasible treatment option in patients with angulated PTBS by reducing complications and prolonging the stent-changing interval.

Tuberculous tracheobronchial stenosis: avoiding resection-when less is more

A case of tracheobronchial stenosis due to tuberculosis in a young woman is presented. Compromised pulmonary function due to near-total obstruction of the proximal left main bronchus was diagnosed. Treatment options included surgical resection, endobronchial dilation or stenting, and argon photocoagulation. An approach was chosen to address symptoms without aggressive resection or commitment to stenting. She remains monitored and, while possibly committed to future intervention, no bridges have been burned with respect to more definitive and invasive therapies. We propose this "less is more" initial approach in all patients when possible. Reserving the more aggressive alternatives for high-risk surgical candidates and those that have been unresponsive to lesser procedures.

Inhibitory Effect of β-Elemene on Human Airway Granulation Tissue in vivo and in vitro

BACKGROUND

Recurrent airway granulation hyperplasia and scar formation make airway stenosis a clinical challenge. Therefore, a new approach for the treatment of airway stenosis is necessary.

OBJECTIVE

To explore the inhibitory effect of β-elemene on the proliferation of fibroblasts and airway granulation.

METHODS

In vivo: (1) study of the effect of local β-elemene injection by bronchoscopy. (2) During bronchoscopy, granulation tissues both before and after treatment were obtained. HE staining was performed and the result compared. In vitro: (1) human airway primary fibroblasts were purified and characterized. (2) Fibroblasts were treated with β-elemene and normal saline (NS) and then examined by optical and electron microscopy. (3) Fibroblasts treated with β-elemene or NS were assessed for viability by tetrazolium salt assay. (4) Apoptotic rates were determined by flow cytometry.

RESULTS

In vivo: (1) after local injection of β- elemene, airway granulation tissue was reduced. (2) Granulation tissue was found to have less edema, and fibroblasts turned into mature fiber cells. In vitro: (1) human airway primary fibroblasts were successfully purified and cultured. (2) Compared with the control group, fibroblasts of the experimental group became clumped, the plasma granules were increased, and some fibroblasts lost their nucleus and organelles. (3) Compared with the control group, reduction of cell viability was detected with increased concentrations of β-elemene. (4) With increased concentrations of β-elemene, apoptotic rates of the fibroblasts were raised compared with the control group.

CONCLUSIONS

β-Elemene may induce apoptosis and necrosis of airway primary fibroblasts and inhibit the proliferation of fibroblasts and airway granulation. The results provide a new approach for the treatment of airway stenosis.