Thermoablative Techniques for Excessive Central Airway Collapse: An Ex Vivo Pilot Study on Sheep Tracheal Tissue

COPD-Associated Expiratory Central Airway Collapse: Current Concepts and New Perspectives

TOPIC IMPORTANCE

COPD-associated expiratory central airway collapse (ECAC) is a frequently overlooked benign airway obstructive disease with complex causes and unclear pathologic and physiologic mechanisms. Although interventions such as noninvasive positive pressure ventilation, airway stenting, and tracheobronchoplasty have shown definite efficacy in the treatment of COPD-associated ECAC, the diagnosis and treatment of this disease remain challenging. This review provides a systematic evaluation and outlook on the epidemiologic features, causes, pathophysiologic characteristics, clinical manifestations, diagnosis, and treatment of COPD-associated ECAC.

REVIEW FINDINGS

COPD-associated ECAC is a benign airway narrowing disease with atypical clinical symptoms and unknown incidence and pathogenesis. Bronchoscopy is considered the gold standard technique for diagnosis of COPD-associated ECAC, with dynamic biphasic CT imaging as an alternative noninvasive method. Noninvasive ventilation treatment can be continued on a long-term basis. Temporary airway stents can alleviate acute and severe tracheobronchomalacia. Long-term stent implantation can be considered after a risk to benefit assessment. Although tracheobronchoplasty has a definite therapeutic effect in patients with severe tracheobronchomalacia, perioperative complications remain a serious issue, and long-term efficacy observation is required. Traditional chinese medicine, other positive expiratory pressure therapies, and lung transplantation have shown potential with limited evidence.

SUMMARY

Although COPD-associated ECAC is attracting considerable attention, its pathophysiologic mechanisms, diagnosis, and management are full of challenges. In the future, randomized controlled trials on different therapies using patient-centered outcomes, cost-effective analysis on different interventions, and consensus guidelines on COPD-associated ECAC will be urgently needed.

Comprehensive Interventional treatment for severe central airway collapse caused by Relapsing Polychondritis: A case report

Relapsing Polychondritis (RP) is a rare systemic inflammatory disease. One major cause of death for patients with RP is severe tracheobronchial tree collapse. Treatment guidelines for RP are mainly based on case reports. We report a rare and challenging case of RP in a patient who experienced asphyxia due to severe central airway collapse. The patient had previously been misdiagnosed with refractory asthma due to recurrent wheezing. Following interventions including bronchoscopic laser tracheobronchoplasty, stent placement, corticosteroid therapy, and both invasive and non-invasive mechanical ventilation, the patient was successfully stabilized and subsequently discharged from the hospital. Notably, after discharge, the patient did not require rehospitalisation for worsening respiratory symptoms and was managed with only a gradually tapering glucocorticoid regimen. In our case report, stent placement rapidly relieved asphyxia due to severe tracheobronchial stenosis, and laser tracheobronchoplasty may be a potential cure for diffuse airway collapse due to RP.

Thermoablative Techniques to Treat Excessive Central Airway Collapse

Excessive central airway collapse (ECAC) is a condition characterized by the excessive narrowing of the trachea and mainstem bronchi during expiration, which can be caused by Tracheobronchomalacia (TBM) or Excessive Dynamic Airway Collapse (EDAC). The initial standard of care for central airway collapse is to address any underlying conditions such as asthma, COPD, and gastro-esophageal reflux. In severe cases, when medical treatment fails, a stent-trial is offered to determine if surgical correction is a viable option, and tracheobronchoplasty is suggested as a definitive treatment approach. Thermoablative bronchoscopic treatments, such as Argon plasma coagulation (APC) and laser techniques (potassium-titanyl-phosphate [KTP], holmium and yttrium aluminum pevroskyte [YAP]) are a promising alternative to traditional surgery. However, further research is needed to assess their safety and effectiveness in humans before being widely used.

Case Report: Endoscopic radiofrequency ablation with radial-EBUS and ROSE

Background

Single pulmonary nodules are a common issue in everyday clinical practice. Currently, there are navigation systems with radial-endobronchial ultrasound and electromagnetic navigation for obtaining biopsies. Moreover, rapid on-site evaluation can be used for a quick assessment. These small lesions, even when they do not have any clinically significant information with positron emission tomography, are important to investigate.

Case description

Radiofrequency and microwave ablation have been evaluated as local treatment techniques. These techniques can be used as therapy for a patient population that cannot be operated on. Currently, one verified operating system is used for endoscopic radiofrequency ablation through the working channel of a bronchoscope.

Conclusion

In our case, a new system was used to perform radiofrequency ablation with long-term follow-up.

Argon Plasma Coagulation (APC) for the Treatment of Excessive Dynamic Airway Collapse (EDAC): An Animal Pilot Study

BACKGROUND

Surgical stabilization of the airway through tracheobronchoplasty (TBP) is the current treatment modality for patients with severe symptomatic excessive dynamic airway collapse. However, TBP is associated with increased morbidity and mortality. Bronchoscopic treatment of the posterior membrane using argon plasma coagulation (APC) may be a safer alternative to TBP in highly selected patients. This study aimed to evaluate the effect of APC in the tracheobronchial tree of a sheep animal model.

PATIENTS AND METHODS

Two adult sheep were used for this study. Under flexible bronchoscopy, the posterior tracheal membrane was treated with precise APC using different power settings. Chest computed tomography was done at 2 days and bronchoscopy was performed at 30 days following initial procedure, before euthanasia. The airways were assessed for the presence of treatment-related histopathologic changes along with expression of genes associated with fibrosis.

RESULTS

There was no perioperative or postoperative morbidity or mortality. Chest computed tomography showed no signs of pneumomediastinum or pneumothorax. Flexible bronchoscopy showed adequate tracheobronchial tissue healing process, independent of the power settings used. Histologic changes demonstrated an increased extent of fibroblastic collagen deposition in the treated posterior membrane when higher power settings were used. In a similar manner, APC treatment managed to activate fibrosis-associated gene transcription factors, with higher settings achieving a higher level of expression.

CONCLUSION

APC at high-power settings achieved higher levels of fibroblast collagen deposition at the posterior membrane and higher expression of fibrosis-associated gene transcription factors, when compared with lower settings.