Tracheobronchial stent sizing and deployment practices airway stenting practices around the world: a survey study

World Association for Bronchology and Interventional Pulmonology (WABIP) guidelines on airway stenting for malignant central airway obstruction

Malignant Central Airway Obstruction (MCAO) encompasses significant and symptomatic narrowing of the central airways that can occur due to primary lung cancer or metastatic disease. Therapeutic bronchoscopy is associated with high technical success and symptomatic relief and includes a wide range of airway interventions including airway stents. Published literature suggests that stenting practices vary significantly across the world primarily due to lack of guidance. This document aims to address this knowledge gap by addressing relevant questions related to airway stenting in MCAO. An international group of 17 experts from 17 institutions across 11 countries with experience in using airway stenting for MCAO was convened as part of this guideline statement through the World Association for Bronchology and Interventional Pulmonology (WABIP). We performed a literature and internet search for reports addressing six clinically relevant questions. This guideline statement, consisting of recommendations addressing these six PICO questions, was formulated by a systematic and rigorous process involving the evaluation of published evidence, augmented with expert experience when necessary. Panel members participated in the development of the final recommendations using the modified Delphi technique.

Biodegradable tracheal stents: our ten-year experience with adult patients

BACKGROUND

Biodegradable (BD) stents made from polydioxanone have been used only in human airways. These stents combine the advantages of classical tracheal stents, and fewer side effects are expected due to their biocompatibility and their time-limited presence in airways. However, new clinical consequences have arisen. Here, the authors share their experiences with BD stents for tracheal indications, focusing on their safety and efficacy.

METHODS

This was a retrospective review of a collected database of adult patients who underwent implantation of biodegradable tracheal stents between September 2013 and December 2022 at the Department of Respiratory Medicine of the 1st Faculty of Medicine in Prague and Thomayer University Hospital. The indications included functionally significant nonmalignant tracheal stenosis and tracheomalacia. Self-expandable, biodegradable, polydioxanone tracheal stents manufactured by ELLA-CS Ltd. (Hradec Kralove, Czech Republic) were implanted during rigid bronchoscopy under general anaesthesia. All patients were followed up in the department and were provided with the necessary care. The main efficacy and safety parameters and relationships were analysed using descriptive statistics and Fisher´s exact, Wilcoxon and Kruskal‒Wallis tests.

RESULTS

A total of 65 stents were implanted in 47 adult patients. During the first two months after implantation, when adequate function was expected, the stent was found to be effective in 26 out of 39 patients who completed this period (66.7%). The clinical effectiveness reached 89.7%, as early restenoses were mostly mild and necessitated treatment in only 4 patients. The frequencies of significant mucostasis, migration and granulation tissue growth were 2.6%, 7.5% and 23.1%, respectively, during this period. Thirty-four participants completed the half-year follow-up period after the first or second stent insertion, and some were followed up beyond this period. Poor control of symptoms, the development of restenosis and the need for interventions were characteristic of this period as the stents degraded. Twenty-two patients who experienced remodelling or stabilization of the tracheal lumen achieved a stent-free state. Seven patients underwent subsequent surgical treatment.

CONCLUSIONS

BD stents are safe and provide adequate tracheal support until they begin to degrade. The use of BD stents necessitates close monitoring of patients and accurate treatment of possible restenosis.

TRIAL REGISTRATION

Based on project NT14146 - Biodegradable stents in the management of the large airways (2013-2015, MZ0/NT), registered on May 1, 2013, in the Research and Development and Innovation Information System of the Czech Republic and at ClinicalTrials.gov (reg. no. NCT02620319, December 2, 2015).

Tracheobronchial stents: an expanding prospect

The first dedicated tracheobronchial silicone stent was designed by the French pulmonologist Jean-Paul Dumon. The most common indications for stenting are to minimise extrinsic airway compression from mass effect, maintain airway patency due to intrinsic obstruction or treat significant nonmalignant airway narrowing or fistulae. Silicone stents require rigid bronchoscopy for insertion; however, they are more readily repositioned and removed compared with metallic stents. Metallic stents demonstrate luminal narrowing when loads are applied to their ends, therefore stents should either be reinforced at the ends or exceed the area of stenosis by a minimum of 5 mm. Nitinol, a nickel-titanium metal alloy, is currently the preferred material used for airway stents. Airway stenting provides effective palliation for patients with severe symptomatic obstruction. Drug-eluting and three-dimensional printing of airway stents present promising solutions to the challenges of the physical and anatomical constraints of the tracheobronchial tree. Biodegradable stents could also be a solution for the treatment of nonmalignant airway obstruction.

Advancements in airway stents: a comprehensive update

PURPOSE OF REVIEW

This review provides an overview of the evolving field of airway stenting (AS), highlighting its relevance in the management of central airway obstruction (CAO). It discusses recent advancements, including 3D-printed silicone stents (3DPSS), metallic stents, biodegradable stents (BS), and drug-eluting stents (DES), which are transforming clinical practice. The review underscores the ongoing challenges in patient selection, stent choice, and long-term management in the context of an evolving landscape.

RECENT FINDINGS

Innovations, particularly 3DPSS, have shown promise in providing patient-specific solutions. These stents offer improved symptom relief, enhanced quality of life, and lower complication rates, especially for complex airway diseases. The use of BS and DES is explored, raising prospects for future applications.

SUMMARY

The evolution of AS reflects a deepening understanding of airway obstructions. Recent innovations, such as 3DPSS, BS, and DES, show considerable promise in addressing the limitations of conventional stents. However, challenges related to complications, patient selection, and long-term management persist, demanding further research. Wide practice variations in the management of AS highlight the need for more clinical data and standardized guidelines. The search for the ideal stent continues, driven by the pursuit of better outcomes for patients with CAO.

Current Practices in Airway Stent Management: A National Survey of US Practitioners

BACKGROUND

Despite a growing number of tracheobronchial stent types and indications, complications remain frequent, and high-quality evidence on practices to prevent stent-related complications is lacking. Understanding current management practice is a first step to designing prospective studies to assess whether specific practices aimed at mitigating stent-related complications improve patient-centered outcomes.

OBJECTIVES

In this study, we aimed to understand current management strategies following tracheobronchial stenting.

METHOD

We performed a nationwide survey of members of the American Association of Bronchology and Interventional Pulmonology (AABIP) and the General Thoracic Surgical Club (GTSC) who place airway stents. The electronic survey captured data on practitioners' demographics, practice setting, airway stent volume, and standard post-stent practices (if any) including the use of medications, mucus clearance devices, surveillance imaging, and surveillance bronchoscopy.

RESULTS

One hundred thirty-eight physicians completed the survey. Respondents were majority male (75.4%) and had diverse training (50.0% completed interventional pulmonary fellowship; 18.1% thoracic surgery; 31.9% other stent training). Post-stent management strategies varied markedly across respondents; 75.4% prescribe at least one medication to prevent post-stent complications, 52.9% perform routine surveillance bronchoscopy in asymptomatic patients, 26.1% prescribe mucus clearance regimens, 16.7% obtain routine computed tomography scans in asymptomatic patients, and 8.3% routinely replace their stents prior to stent failure.

CONCLUSIONS

In this national survey of practitioners who place airway stents, there was marked heterogeneity in post-stent management approaches. Further studies are needed to identify which, if any, of these strategies improve patient-centered outcomes.

A single-tube-braided stent for various airway structures

Background: Airway stent has been widely used in airway procedures. However, the metallic and silicone tubular stents are not customized designed for individual patients and cannot adapt to complicated obstruction structures. Other customized stents could not adapt to complex airway structures with easy and standardized manufacturing methods.

Object: This study aimed to design a series of novel stents with different shapes which can adapt to various airway structures, such as the “Y” shape structure at the tracheal carina, and to propose a standardized fabrication method to manufacture these customized stents in the same way.

Methods: We proposed a design strategy for the stents with different shapes and introduced a braiding method to prototype six types of single-tube-braided stents. Theoretical model was established to investigate the radial stiffness of the stents and deformation upon compression. We also characterized their mechanical properties by conducting compression tests and water tank tests. Finally, a series of benchtop experiments and ex vivo experiments were conducted to evaluate the functions of the stents.

Results: The theoretical model predicted similar results to the experimental results, and the proposed stents could bear a compression force of 5.79N. The results of water tank tests showed the stent was still functioning even if suffering from continuous water pressure at body temperature for a period of 30 days. The phantoms and ex-vivo experiments demonstrated that the proposed stents adapt well to different airway structures.

Conclusion: Our study offers a new perspective on the design of customized, adaptive, and easy-to-fabricate stents for airway stents which could meet the requirements of various airway illnesses.

Therapeutic bronchoscopy for malignant central airway obstruction: impact on quality of life and risk-benefit analysis

PURPOSE OF REVIEW

Malignant central airway obstruction (CAO) is a common complication in cancer and confers significant symptom burden and reduction in quality of life. Multiple bronchoscopic interventions exist for malignant CAO. In this review, we discuss the role of therapeutic bronchoscopy in the management of malignant CAO, emphasizing its impact on symptom control and quality of life while balancing the risks and benefits of intervention.

RECENT FINDINGS

Significant practice variations exist among practitioners of therapeutic bronchoscopy, and limited data exist to guide real-time clinical decision-making. Recent analyses demonstrate that therapeutic bronchoscopy is effective for symptoms associated with malignant CAO with infrequent complications. These studies also show that many of the improvements in symptoms and quality of life are sustained after intervention and are associated with improved overall survival in patients with malignant CAO. Recent data have also shown that the improvement in symptoms associated with therapeutic bronchoscopy may enable more definitive cancer treatment, further improving patient outcomes.

SUMMARY

Therapeutic bronchoscopy is safe and effective at improving patient-centered outcomes in malignant CAO. Research is ongoing to better understand its optimal role in this setting, refine decision-making regarding advanced bronchoscopic interventions, and further improve patient outcomes.

Central airway obstruction treatment with self-expanding covered Y-carina nitinol stents: A single center retrospective analysis

Background

Central airway obstruction (CAO) is one of the most challenging, potentially lethal complications in malignant and benign respiratory diseases. Worsening dyspnea is also a relevant cause for reduced quality of life in such patients. Here, we present our data on the application of covered, self‐expanding Y‐carina nitinol stents due to benign and malignant diseases.

Methods

We retrospectively identified 27 patients who had undergone 31 rigid bronchoscopies with implantation of covered Y‐carina nitinol stents over a period of 10 years in order to evaluate indication, clinical course, and outcome.

Results

Short‐term survival of successfully stented patients with palliative and curative treatment goal did not differ, allowing for diagnosis independent indication. With respect to overall survival, patients with endoluminal obstruction benefited most compared to patients with fistula and/or external compression. Granulation tissue formation (61.3%) and mucus plugging (80.6%) were the most frequent complications. Material defect (6.5%) and migration (3.2%) were rare complications that could be handled by revisional rigid bronchoscopy and stent exchange in some cases.

Conclusions

Implantation of self‐expanding covered Y‐carina nitinol stents via rigid bronchoscopy is a feasible and safe treatment option for benign and malignant central airway obstruction. Especially in palliative, malignant airway stenosis, stenting might facilitate additional treatment options and optimize dyspnea and eventually quality of life.

[Tracheobronchial stenting in patients with non-resectable tumors complicated by airway stenosis]

OBJECTIVE

To study the results and efficiency of tracheobronchial stenting in patients with unresectable tumors complicated by stenosis of central airways.

MATERIAL AND METHODS

We analyzed the results of tracheobronchial stenting in 23 patients with unresectable tumors complicated by stenosis of central airways between 2016 and 2021.

RESULTS

Technical and clinical success rate was 100%. No intraoperative complications were noted. Dyspnea regressed in all patients in early postoperative period. Moreover, there was objective improvement in lung ventilation with increase in lung capacity (from 2.1±0.4 to 2.7±0.5 l; p<0.05), forced expiratory volume (from 1.2±0.5 to 1.8±0.4 l; p<0.05), partial pressure of oxygen in arterial blood (from 47±7.4 to 85±6.3 mm Hg; p<0.05) and arterial oxygen saturation (from 86.1±8.2 to 93.1±5.1%; p<0.05). One patient developed massive bleeding due to tumor decay on the 3^rd day after surgery. In 2 patients, stent obturation with a «mucus plug» was observed after 2-3 postoperative days. In 3 months after surgery, 21.8% of patients had disturbances of external respiration accompanied by mild dyspnea due to granulation tissue growth. Stent migration in 3 months after endoscopic stenting was recorded in 1 patient. Three-month mortality was 26.1%.

CONCLUSION

Tracheobronchial stenting is a safe and effective minimally invasive surgical intervention. As a part of palliative care, this procedure improves functional and clinical parameters of pulmonary ventilation and reduces the incidence of complications. Thus, quality of life in patients with unresectable tumors complicated by airway stenosis is improved.

Current practices in the management of central airway obstruction

PURPOSE OF REVIEW

Airway obstruction continues to cause substantial pulmonary morbidity and mortality. We present a review of classic, current, and evolving management techniques, highlighting recently published studies on the topic. Recommendations have historically been primarily based on anecdotal experience, case reports, and retrospective studies, but more solid evidence has emerged in the last decade.

RECENT FINDINGS

Novel endobronchial stents are being developed to mitigate the issues of stent migration, mucus plugging, fracture, and granulation tissue formation. Endobronchial drug delivery has become an active area of translational and clinical research, especially with regards to antineoplastic agents used for malignant airway stenosis. Even classic or updated techniques such as spray cryotherapy, injections of mitomycin-c, and balloon dilation have recently been examined in methodologically sound studies. Finally, recently published data have confirmed that patient breathlessness and quality of life improve significantly with therapeutic airway interventions. A multimodal and multidisciplinary approach to patient care is key to achieving the best outcomes.

SUMMARY

The treatment of central airway stenosis is often multimodal and should focus on patient-centric factors, taking into account risks and benefits of the procedure, operator, and center expertise, and always occur in the context of a multidisciplinary approach. Evidence-based clinical research is increasingly driving patient management.