Safety and efficacy of a novel transbronchial radiofrequency ablation system for lung tumours: One year follow-up from the first multi-centre large-scale clinical trial (BRONC-RFII).

BACKGROUND AND OBJECTIVE: Radiofrequency ablation (RFA) is an emerging treatment of lung cancer, yet it is accompanied by certain safety concerns and operational limitations. This first multi-centre, large-scale clinical trial aimed to investigate the technical performance, efficacy and safety of an innovative transbronchial RFA system for lung tumours. METHODS: The study enrolled patients with malignant lung tumours who underwent transbronchial RFA using an automatic saline microperfusion system between January 2021 and December 2021 across 16 medical centres. The primary endpoint was the complete ablation rate. The performance and safety of the technique, along with the 1-year survival rates, were evaluated. RESULTS: This study included 126 patients (age range: 23-85 years) with 130 lung tumours (mean size: 18.77 × 14.15 mm) who had undergone 153 transbronchial RFA sessions, with a technique success rate of 99.35% and an average ablation zone size of 32.47 mm. At the 12-month follow-up, the complete ablation rate and intrapulmonary progression-free survival rates were 90.48% and 88.89%, respectively. The results of patients with ground-glass nodules (GGNs) were superior to those of the patients with solid nodules (12-month complete ablation rates: solid vs. pure GGN vs. mixed GGN: 82.14% vs. 100% vs. 96.08%, p = 0.007). No device defects were reported. Complications such as pneumothorax, haemoptysis, pleural effusion, pulmonary infection and pleural pain were observed in 3.97%, 6.35%, 8.73%, 11.11% and 10.32% of patients, respectively. Two subjects died during the follow-up period. CONCLUSION: Transbronchial RFA utilizing an automatic saline microperfusion system is a viable, safe and efficacious approach for the treatment for lung tumours, particularly for patients with GGNs.

5G-Based Remote Virtual Bronchoscopic Navigation-Guided Transbronchial Lung Biopsy for Diagnosis of Lung Cancer: Description of 2 Cases.

INTRODUCTION: Bronchoscopic navigation combined with endobronchial ultrasound-guided transbronchial lung biopsy (EBUS-TBLB) is an important approach for the diagnosis of peripheral pulmonary lesions (PPL). The fifth-generation (5G) network, characterized by low latency and high stability, has shown promising possibilities in telemedicine for remote areas. METHODS: We present two cases of PPL in primary hospitals without navigation equipment. The EBUS-TBLB was performed with the guidance of remote augmented reality virtual bronchoscopic navigation (VBN) based on a 5G network. In practice, the 5G network could enable the matching of actual/virtual bronchoscopic images and navigation paths in real time, as well as high-speed transmission at long distances (>20 km), without any visual delay (<500 ms). CONCLUSION: Both patients were successfully diagnosed with lung cancer after accurate positioning and obtaining biopsies of target lesions. This 5G-based remote VBN-guided EBUS-TBLB appears to be safe with reliable connections in both cases and shows potential for cost-effectiveness. It would be an optimal resource for undeveloped regions and/or regions lacking endoscopists with extensive experience in navigation-related procedures.

The Novel Application of Robotic-Assisted Bronchoscopy Combined with Photodynamic Therapy for Adenoid Cystic Carcinoma of the Trachea.

Robotic platforms have been widely used in the various fields of clinical diagnosis and therapy of diseases in the past decade. Robotic-assisted bronchoscopy (RAB) demonstrates its advantages of visibility, flexibility, and stability in comparison to conventional bronchoscopic techniques. Improving diagnostic yield and navigation yield for peripheral pulmonary lesions has been defined; however, RAB platform of treatment was not reported. In this article, we report a case of a 52-year-old woman who was diagnosed with the tracheal adenoid cystic carcinoma and recurred in the second postoperative year, leading to the involvement of the entire tracheal wall and lumen obstruction. Since the lesion was inoperable, we combined RAB and photodynamic therapy (PDT) for the patient. The potential advantages of using RAB for PDT delivery include precise light irradiation of target lesions and stable intra-operative control over the long term. This is a novel application of RAB combined with PDT for airway diseases. The case report may provide a new insight into the diagnosis and treatment of pulmonary diseases. In addition to improving the diagnostic rates, the RAB platform may also play an important role in the treatment of airway and lung disease in the future.

Clinical application of endobronchial ultrasonography-guided transbronchial needle aspiration biopsy-a single center, large sample, real-world study.

BACKGROUND: Endobronchial ultrasonography-guided transbronchial needle aspiration biopsy (EBUS-TBNA) has been used for more than 10 years in China. Its clinical application and diagnostic value in different diseases with large sample was lack of report. METHODS: A retrospective analysis was performed about the application and diagnostic value of EBUS-TBNA in different disease of patients in Respiratory Intervention Center of Guangzhou Institute of Respiratory Health from January 2012 to July 2020. RESULTS: A total 5758 patients were included with 182 patients excluded for lack of information. Finally, data of 5576 patients (3798 males and 1778 females) were analyzed. For anesthetize, most patients were undergoing general anesthesia of intravenous with spontaneous breathing (69.4%), followed by general anesthesia of intravenous and inhalation with tracheal intubation and mechanical ventilation (17.9%) and conscious sedation and analgesia (12.8%). Lymph nodes were the main sites of biopsy obtained (76.4%). Tumors accounted for the highest proportion of disease (66.4%), followed by infection diseases (9.9%), sarcoidosis (3.9%), lymphoma (1.1%), and others (18.7%). The sensitivity of EBUS-TBNA for diagnosis of tumor was 89.7%, and 40.8% for infection diseases. There were significant differences in the puncture site and proportions of diseases between male and females (both p < 0.05). Higher diagnostic value was found in male patients (p < 0.05). CONCLUSION: EBUS-TBNA has good diagnostic value for different mediastinal and central pulmonary space-occupying lesions diseases, with highest sensitivity for tumors. Higher diagnostic value was found in male patients.

Distinguishing bronchoscopically observed anatomical positions of airway under by convolutional neural network.

Background: Artificial intelligence (AI) technology has been used for finding lesions via gastrointestinal endoscopy. However, there were few AI-associated studies that discuss bronchoscopy. Objectives: To use convolutional neural network (CNN) to recognize the observed anatomical positions of the airway under bronchoscopy. Design: We designed the study by comparing the imaging data of patients undergoing bronchoscopy from March 2022 to October 2022 by using EfficientNet (one of the CNNs) and U-Net. Methods: Based on the inclusion and exclusion criteria, 1527 clear images of normal anatomical positions of the airways from 200 patients were used for training, and 475 clear images from 72 patients were utilized for validation. Further, 20 bronchoscopic videos of examination procedures in another 20 patients with normal airway structures were used to extract the bronchoscopic images of normal anatomical positions to evaluate the accuracy for the model. Finally, 21 respiratory doctors were enrolled for the test of recognizing corrected anatomical positions using the validating datasets. Results: In all, 1527 bronchoscopic images of 200 patients with nine anatomical positions of the airway, including carina, right main bronchus, right upper lobe bronchus, right intermediate bronchus, right middle lobe bronchus, right lower lobe bronchus, left main bronchus, left upper lobe bronchus, and left lower lobe bronchus, were used for supervised machine learning and training, and 475 clear bronchoscopic images of 72 patients were used for validation. The mean accuracy of recognizing these 9 positions was 91% (carina: 98%, right main bronchus: 98%, right intermediate bronchus: 90%, right upper lobe bronchus: 91%, right middle lobe bronchus 92%, right lower lobe bronchus: 83%, left main bronchus: 89%, left upper bronchus: 91%, left lower bronchus: 76%). The area under the curves for these nine positions were >0.98. In addition, the accuracy of extracting the images via the video by the trained model was 94.7%. We also conducted a deep learning study to segment 10 segment bronchi in right lung, and 8 segment bronchi in Left lung. Because of the problem of radial depth, only segment bronchi distributions below right upper bronchus and right middle bronchus could be correctly recognized. The accuracy of recognizing was 84.33 ± 7.52% by doctors receiving interventional pulmonology education in our hospital over 6 months. Conclusion: Our study proved that AI technology can be used to distinguish the normal anatomical positions of the airway, and the model we trained could extract the corrected images via the video to help standardize data collection and control quality.

Long-term efficacy and safety of the Dumon stent for treatment of benign airway stenosis.

BACKGROUND: The long-term efficacy of the Dumon stent in the treatment of benign airway stenosis is unclear. OBJECTIVE: The objective of this study was to evaluate the long-term efficacy and safety of the Dumon stent in patients with benign airway stenosis. METHODS: We retrospectively reviewed patients with benign airway stenosis who were treated with a Dumon stent at the First Affiliated Hospital of Guangzhou Medical University between March 2014 and October 2021. We included patients with successful removal of silicone stents after implantation. The clinical data and information on bronchoscopic interventional procedures and related complications were collected and analyzed. RESULTS: Ninety-nine patients with benign airway stenosis were included. The stent was placed mainly in the trachea (44.4%) and left main bronchus (43.4%). The main type of stenosis was post-tuberculosis bronchial stenosis (57.6%). The overall cure rate was 60.6%. Stent-related complications included retention of secretions (70.7%), granuloma formation (67.7%), stent angulation (21.2%), and stent migration (12.1%). The stent was less effective for left main bronchus stenosis (p = 0.012). Multivariate logistic regression analysis identified that stent placement for more than 13 months, a stent-intervention number of ⩽ 1 predicted a favorable outcome. CONCLUSION: The efficacy and safety of the Dumon stent for benign airway stenosis need improvement. The stent is less effective for left main bronchus stenosis; regular follow-up is required in such cases. Stent placement for > 13 months and no more than once stent intervention within a 6-month period were associated with a favorable outcome.

Endobronchial optical coherence tomography or computed tomography for evaluating progression of bronchiectasis.

Background: The early radiological signs of progression in bronchiectasis remain unclear. The objective of the present study was to compare endobronchial optical coherence tomography (EB-OCT) and chest computed tomography (CT) for the evaluation of radiological progression of bronchiectasis via stratification of the presence (TW+) or absence (TW-) of thickened-walled bronchioles surrounding dilated bronchi in patients with bronchiectasis based on CT, and determine the risk factors. Methods: In this prospective cohort study, we performed both chest CT and EB-OCT at baseline and 5-year follow-up, to compare changes in airway calibre metrics. We evaluated bacterial microbiology, sputum matrix metalloproteinase-9 levels and free neutrophil elastase activity at baseline. We compared clinical characteristics and airway calibre metrics between the TW+ and TW- groups. We ascertained radiological progression at 5 years via CT and EB-OCT. Results: We recruited 75 patients between 2014 and 2017. At baseline, EB-OCT metrics (mean luminal diameter (p=0.017), inner airway area (p=0.005) and airway wall area (p=0.009) of seventh- to ninth-generation bronchioles) were significantly greater in the TW+ group than in the TW-group. Meanwhile, EB-OCT did not reveal bronchiole dilatation (compared with the same segment of normal bronchioles) surrounding nondilated bronchi on CT in the TW- group. At 5 years, 53.1% of patients in the TW+ group progressed to have bronchiectasis measured with EB-OCT, compared with only 3.3% in TW- group (p<0.05). 34 patients in the TW+ group demonstrated marked dilatation of medium-sized and small airways. Higher baseline neutrophil elastase activity and TW+ bronchioles on CT predicted progression of bronchiectasis. Conclusion: Thickened-walled bronchioles surrounding the dilated bronchi, identified with EB-OCT, indicates progression of bronchiectasis.

Airway morphological abnormalities of bronchiolitis assessed by endobronchial optical coherence tomography.

BACKGROUND: A few studies have reported the medium-sized and small airway morphological abnormalities of bronchiolitis. Whether spirometry or impulse oscillometry (IOS) is correlated with airway remodeling of bronchiolitis remains unclear. OBJECTIVES: Aiming to demonstrate the airway morphological abnormalities of bronchiolitis obliterans (BO) and diffuse panbronchiolitis (DPB) assessed by endobronchial optical coherence tomography (EB-OCT), and elucidate whether spirometric and IOS parameters have correlation with the airway remodeling of bronchiolitis. METHODS: We recruited 18 patients with bronchiolitis (BO, n = 9; DPB, n = 9) and 17 control subjects. Assessments of clinical features, St. George's respiratory questionnaire (SGRQ), chest computed tomography (CT), spirometry, IOS, and EB-OCT were performed in all enrolled subjects. The correlation between EB-OCT and lung function parameters was studied and analyzed. RESULTS: The magnitude of abnormalities of spirometric and IOS parameters was significantly greater in patients with bronchiolitis than that in control subjects (p < 0.05). Patients with BO had notably lower forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC, maximal mid-expiratory flow (MMEF)% pred and higher resonant frequency (Fres), and area of reactance (AX) than those with DPB (p < 0.05). The EB-OCT measurement among patients with bronchiolitis and between the bronchus in the left and the right lung demonstrated a heterogeneous distribution of airway calibers, presenting a high intra- and inter-individual variability. Patients with bronchiolitis had notably greater airway wall area (p < 0.05) compared with control, while BO presented greater magnitude of airway abnormalities than DPB. Fres and the difference in airway resistance at 5 and 20 Hz (R5-R20) correlated negatively with medium-sized and small airway inner area, and correlated positively with airway wall area (p < 0.05), whose correlation coefficients were higher than those of spirometric parameters. CONCLUSION: Bronchiolitis, BO and DPB, manifested a heterogeneous distribution of airway calibers with significant intra- and inter-individual variability. IOS parameters, rather than spirometry, correlated better with medium-sized and small airway remodeling in bronchiolitis assessed by EB-OCT measurement.

Risk factors and prognosis of airway complications in lung transplant recipients: A systematic review and meta-analysis.

BACKGROUND: Airway complications (AC) are one of leading causes of morbidity and mortality after lung transplant (LTx), but their predictors and outcomes remain controversial. This study aimed to identify potential risk factors and prognosis of AC. METHODS: A systematic review was performed by searching PubMed, Embase, and Cochrane Library. All observational studies reporting outcome and potential factors of AC after LTx were included. The incidence, mortality, and estimated effect of each factor for AC were pooled by using the fixed-effects model or random-effects model. RESULTS: Thirty-eight eligible studies with 52,116 patients undergoing LTx were included for meta-analysis. The pooled incidence of AC was 12.4% (95% confidence interval [CI] 9.5-15.8) and the mean time of occurrence was 95.6 days. AC-related mortality rates at 30-days, 90-days, 6 months, 1 year, and 5 years were 6.7%, 17.9%, 18.2%, 23.6%, and 66.0%, respectively. Airway dehiscence was the most severe type with a high mortality at 30 days (60.9%, 95% CI 20.6-95.2). We found that AC was associated with a higher risk of mortality in LTx recipients (hazard ratio [HR] 1.71, 95% CI 1.04-2.81). Eleven significant predictors for AC were also identified, including male donor, male recipient, diagnosis of COPD, hospitalization, early rejection, postoperative infection, extracorporeal membrane oxygenation, mechanical ventilation, telescopic anastomosis, and bilateral and right-sided LTx. CONCLUSION: AC was significantly associated with higher mortality after LTx, especially for dehiscence. Targeted prophylaxis for modifiable factors and enhanced early bronchoscopy surveillance after LTx may improve the disease burden of AC.

Case report: Spontaneous remission in lung carcinoma with a late relapse after adjuvant immunotherapy: Exceptional tumor micro-environment.

Spontaneous remission (SR) of local recurrence after adjuvant immunotherapy has rarely been reported, and the underlying mechanism is poorly understood. Herein, we reported a patient with stage cT2aN2M0 squamous cell lung carcinoma who received neoadjuvant and adjuvant treatment with nivolumab plus chemotherapy. The patient experienced a late relapse in the subcarinal lymph node seven months after the last dosage of treatment but achieved SR in the next three months without additional antitumor therapy. The complete response lasted for eleven months and counting. Notably, high copies of pathogenic microorganisms were detected in the patient's bronchoalveolar lavage fluid along with the recurrence but disappeared after SR. The patient also experienced a lymph node puncture-induced fever but had no other symptoms. A longitudinal analysis of infiltrated immune cells in the recurrent lymph node was performed by multiplex immunofluorescence and whole transcriptome sequencing, which revealed that CD8+ T cells were recruited during the initial relapse, specifically in the stromal area, then migrated into the tumor tissue, and continued to increase after elimination of tumor cells. Meanwhile, the initial recruitment of CD8+ T cells was coupled with a higher proportion of B cells, and the abundant neutrophil population was synchronous with the infiltration of CD8+ T cells into tumor cells. This is the first report on an Non-small cell lung cancer (NSCLC) patient with a late relapse after adjuvant immune checkpoint inhibitor (ICI) therapy who achieved SR. Our case highlights the complexity and plasticity of antitumor immunity and is expected to help find efficient strategies against the resistance of ICI treatment.

Deep Learning-Based Segmentation of Airway Morphology from Endobronchial Optical Coherence Tomography.

BACKGROUND: Manual measurement of endobronchial optical coherence tomography (EB-OCT) images means a heavy workload in the clinical practice, which can also introduce bias if the subjective opinions of doctors are involved. OBJECTIVE: We aim to develop a convolutional neural network (CNN)-based EB-OCT image analysis algorithm to automatically identify and measure EB-OCT parameters of airway morphology. METHODS: The ResUNet, MultiResUNet, and Siamese network were used for analyzing airway inner area (Ai), airway wall area (Aw), airway wall area percentage (Aw%), and airway bifurcate segmentation obtained from EB-OCT imaging, respectively. The accuracy of the automatic segmentations was verified by comparing with manual measurements. RESULTS: Thirty-three patients who were diagnosed with asthma (n = 13), chronic obstructive pulmonary disease (COPD, n = 13), and normal airway (n = 7) were enrolled. EB-OCT was performed in RB9 segment (lateral basal segment of the right lower lobe), and a total of 17,820 OCT images were collected for CNN training, validation, and testing. After training, the Ai, Aw, and airway bifurcate were readily identified in both normal airway and airways of asthma and COPD. The ResUNet and the MultiResUNet resulted in a mean dice similarity coefficient of 0.97 and 0.95 for Ai and Aw segmentation. The accuracy Siamese network in identifying airway bifurcate was 96.6%. Bland-Altman analysis indicated there was a negligible bias between manual and CNN measurements for Ai (bias = -0.02 to 0.01, 95% CI = -0.12 to 0.14) and Aw% (bias = -0.06 to 0.12, 95% CI = -1.98 to 2.14). CONCLUSION: EB-OCT imaging in conjunction with ResUNet, MultiResUNet, and Siamese network could automatically measure normal and diseased airway structure with an accurate performance.

Virtual bronchoscopic navigation and endobronchial ultrasound with a guide sheath without fluoroscopy for diagnosing peripheral pulmonary lesions with a bronchus leading to or adjacent to the lesion: A randomized non-inferiority trial.

BACKGROUND AND OBJECTIVE: Transbronchial sampling of peripheral pulmonary lesions (PPLs) is routinely performed under fluoroscopy. However, advanced ancillary techniques have become available, such as virtual bronchoscopic navigation (VBN) and radial endobronchial ultrasound with a guide sheath (rEBUS-GS). This study was performed to determine whether the diagnostic utility of VBN and rEBUS with a GS is similar with or without fluoroscopy. METHODS: This multicenter non-inferiority trial randomized patients to a VBN-rEBUS-GS with or without fluoroscopy group at three centres. The primary endpoint was the diagnostic yield. The secondary endpoints were the time for rEBUS, GS, and the total operation. Complications were also recorded. RESULTS: Four hundred and ninety-six subjects were assessed and 426 subjects were included in the analysis (212 in non-fluoroscopy-guided-group and 214 in fluoroscopy-guided-group). The diagnostic yield in the non-fluoroscopy-guided-group (84.0%) was not inferior to that in the fluoroscopy-guided-group (84.6%), with a diagnostic difference of -0.6% (95% CI: -6.4%, 5.2%). Multivariable analysis confirmed that bronchus sign and lesion nature were valuable diagnostic predictors in non-fluoroscopy-guided-group. The non-fluoroscopy-guided-group had shorter rEBUS, GS, and total operation time. No severe complications occurred in either group. CONCLUSION: Transbronchial diagnosis of PPLs suspicious of malignancy and presence of a bronchus leading to or adjacent to lesions using VBN-rEBUS-GS without fluoroscopy is a safe and effective method that is non-inferior to VBN-rEBUS-GS with fluoroscopy. Bronchus leading to lesions and malignant nature are associated with high diagnostic yield in VBN-rEBUS-GS without fluoroscopy for the diagnosis of PPLs.

Hierarchical clock-scale hand-drawn mapping as a simple method for bronchoscopic navigation in peripheral pulmonary nodule.

BACKGROUND: A feasible and economical bronchoscopic navigation method in guiding peripheral pulmonary nodule biopsy is lacking. OBJECTIVE: To investigate the utility of hierarchical clock-scale hand-drawn mapping for bronchoscopic navigation in peripheral pulmonary nodules. METHODS: We developed a hierarchical clock-scale hand-drawn mapping for bronchoscopic navigation in peripheral pulmonary nodules. Patients with peripheral pulmonary nodules were recruited and assigned to two groups in this retrospective study, subjects in VBN group received conventional bronchoscopy in conjunction with virtual bronchoscopic navigation (VBN) and radial probe endobronchial ultrasound (RP-EBUS) for biopsy (VBN group), while HBN group underwent ultrathin bronchoscopy and RP-EBUS under the guidance of hand-drawn bronchoscopic navigation (HBN). The demographic characteristics, procedural time, operating cost and diagnostic yield were compared between these two groups. RESULTS: Forty-eight patients with peripheral pulmonary nodule were enrolled in HBN group, while 42 in VBN group. There were no significant differences between VBN and HBN groups in terms of age, gender, lesion size, location and radiographic type. The time of planning pathway (1.32 vs. 9.79 min, P < 0.001) and total operation (23.63 vs. 28.02 min, P = 0.002), as well as operating cost (758.31 ± 125.21 vs.1327.70 ± 116.25 USD, P < 0.001) were markedly less in HBN group, compared with those in VBN group. The pathological diagnostic efficiency of benign and malignant disease in HBN group appeared similar with those in VBN group, irrespective of the size of pulmonary lesion (larger or smaller than 20 mm). The total diagnostic yield of HBN had no marked difference from that of VBN (75.00% vs. 61.90%, P = 0.25). CONCLUSIONS: Hierarchical clock-scale hand-drawn mapping for bronchoscopic navigation could serve as a feasible and economical method for guiding peripheral pulmonary nodule biopsy, providing a comparable diagnostic yield in comparison with virtual bronchoscopic navigation.

Proposed clinical phases for the improvement of personalized treatment of checkpoint inhibitor-related pneumonitis.

Background: Checkpoint inhibitor-related pneumonitis (CIP) is a lethal immune-related adverse event. However, the development process of CIP, which may provide insight into more effective management, has not been extensively examined. Methods: We conducted a multicenter retrospective analysis of 56 patients who developed CIP. Clinical characteristics, radiological features, histologic features, and laboratory tests were analyzed. After a comprehensive analysis, we proposed acute, subacute, and chronic phases of CIP and summarized each phase's characteristics. Results: There were 51 patients in the acute phase, 22 in the subacute phase, and 11 in the chronic phase. The median interval time from the beginning of CIP to the different phases was calculated (acute phase: ≤4.9 weeks; subacute phase: 4.9~13.1 weeks; and chronic phase: ≥13.1 weeks). The symptoms relieved from the acute phase to the chronic phase, and the CIP grade and Performance Status score decreased (P<0.05). The main change in radiologic features was the absorption of the lesions, and 3 (3/11) patients in the chronic phase had persistent traction bronchiectasis. For histologic features, most patients had acute fibrinous pneumonitis in the acute phase (5/8), and most had organizing pneumonia in the subacute phase (5/6). Other histologic changes advanced over time, with the lesions entering a state of fibrosis. Moreover, the levels of interleukin-6, interleukin-10 and high-sensitivity C-reactive protein (hsCRP) increased in the acute phase and decreased as CIP progressed (IL-6: 17.9 vs. 9.8 vs. 5.7, P=0.018; IL-10: 4.6 vs 3.0 vs. 2.0, P=0.041; hsCRP: 88.2 vs. 19.4 vs. 14.4, P=0.005). Conclusions: The general development process of CIP can be divided into acute, subacute, and chronic phases, upon which a better management strategy might be based devised.

A clinical and canine experimental study in small-airway response to bronchial thermoplasty: Role of the neuronal effect.

BACKGROUND: The effects of bronchial thermoplasty (BT) on smooth muscle (SM) and nerves in small airways are unclear. METHODS: We recruited 15 patients with severe refractory asthma, who received BT treatment. Endobronchial optical-coherence tomography (EB-OCT) was performed at baseline, 3 weeks' follow-up and 2 years' follow-up to evaluate the effect of BT on airway structure. In addition, we divided 12 healthy beagles into a sham group and a BT group, the latter receiving BT on large airways (inner diameter >3 mm) of the lower lobe. The dogs' lung lobes were resected to evaluate histological and neuronal changes of the treated large airways and untreated small airways 12 weeks after BT. RESULTS: Patients receiving BT treatment had significant improvement in Asthma Control Questionnaire (ACQ) scores and significant reduction in asthma exacerbations. EB-OCT results demonstrated a notable increase in inner-airway area (Ai) and decrease in airway wall area percentage (Aw%) in both large (3rd-to 6th-generation) and small (7th-to 9th-generation) airways. Furthermore, the animal study showed a significant reduction in the amount of SM in BT-treated large airways but not in untreated small airways. Protein gene product 9.5 (PGP9.5)-positive nerves and muscarinic receptor 3 (M3 receptor) expression in large and small airways were both markedly decreased throughout the airway wall 12 weeks after BT treatment. CONCLUSIONS: BT significantly reduced nerves, but not SM, in small airways, which might shed light on the mechanism of lung denervation by BT.

Feasibility and Safety of Radiofrequency Ablation Guided by Bronchoscopic Transparenchymal Nodule Access in Canines.

BACKGROUND: The treatment of pulmonary malignancies remains a challenge. The efficacy and safety of bronchoscopic radiofrequency ablation (RFA) for the treatment of lung cancer are not well elucidated. OBJECTIVE: This study aimed to evaluate the feasibility and safety of RFA guided by bronchoscopic transparenchymal nodule access (BTPNA) in vivo. METHODS: In an attempt to determine the parameters of RFA, we first performed RFA in conjunction with automatic saline microperfusion in the lung in vitro with various ablation energy (10, 15, 20, 25, and 30 W) and ablation times (3, 5, 8, and 10 min). The correlation between ablated area and RFA parameter was recorded and analyzed. Further, we conducted a canine study with RFA by BTPNA in vivo, observing the ablation effect and morphological changes in the lung assessed by chest CT and histopathologic examination at various follow-up time points (1 day, n = 3; 30 days, n = 4; 90 days, n = 4). The related complications were also observed and recorded. RESULTS: More ablation energy, but not ablation time, induced a greater range of ablation area in the lung. Ablation energy applied with 15 W for 3 min served as the appropriate setting for pulmonary lesions ≤1 cm. RFA guided by BTPNA was performed in 11 canines with 100% success rate. Inflammation, congestion, and coagulation necrosis were observed after ablation, which could be repaired within 7 days; subsequently, granulation and fibrotic scar tissue developed after 30 days. No procedure-related complication occurred during the operation or in the follow-up periods. CONCLUSION: The novel RFA system and catheter in conjunction with automatic saline microperfusion present a safe and feasible modality in pulmonary parenchyma. RFA guided by BTPNA appears to be well established with an acceptable tolerance; it might further provide therapeutic benefit in pulmonary malignancies.