Alternative Splicing Is a Major Factor Shaping Transcriptome Diversity in Mild and Severe Chronic Obstructive Pulmonary Disease

The role of alternative splicing in chronic obstructive pulmonary disease (COPD) is still largely unknown. We aimed to investigate the differences in alternatively splicing events between patients with mild-to-moderate and severe COPD compared with non-COPD control subjects and to identify splicing factors associated with aberrant alternative splicing in COPD. For this purpose, we performed genome-wide RNA-sequencing analysis of bronchial brushings from 23 patients with mild-to-moderate COPD, 121 with severe COPD, and 23 non-COPD control subjects. We found a significant difference in the frequency of alternative splicing events in patients with mild-to-moderate and severe COPD compared with non-COPD control subjects. There were from two to eight times (depending on event type) more differential alternative splicing events in the severe than in the mild-to-moderate stage. The severe COPD samples showed less intron retention and more exon skipping. It is interesting that the transcript levels of the top 10 differentially expressed splicing factors were significantly correlated with the percentage of many alternatively spliced transcripts in severe COPD. The aberrant alternative splicing in severe COPD was predicted to increase the overall protein-coding capacity of gene products. In conclusion, we observed large and significant differences in alternative splicing between bronchial samples of patients with COPD and control subjects, with more events observed in severe than in mild-to-moderate COPD. The changes in the expression of several splicing factors correlated with prevalence of alternative splicing in severe COPD. Alternative splicing can indirectly impact gene expression by changing the relative abundance of protein-coding isoforms potentially influencing pathophysiological changes. The results provide a better understanding of COPD-related alternative splicing changes.

Optimizing clinical outcomes for bronchoscopic lung volume reduction with Zephyr® valves

Bronchoscopic lung volume reduction treatment with Zephyr one-way valves is an effective guideline-based treatment option for patients with severe emphysema and hyperinflation. However, in some cases the treatment response is less than anticipated or there might be a loss of initial treatment effect. Reasons for the lack of response can include incorrect assessment of collateral ventilation, improper valve placement, or patient related factors. Loss of initial benefit can be due to granulation tissue formation and subsequent valve dysfunction, or there may be side effects such as excessive coughing or infectious problems. Careful follow-up after treatment with valves is important and evaluation with a CT scan and/or bronchoscopy is helpful if there is no improvement after treatment or loss of initial benefit. This paper aims to describe the most important causes and provide a strategy of how to approach and manage these patients.

The agreement between bronchoalveolar lavage, bronchial wash and sputum culture: a retrospective study

PURPOSE

Bronchoalveolar lavage is commonly used in clinical practice for unresolved pneumonia. However, bronchoalveolar lavage is not suitable for all patients as it is an invasive procedure and can worsen oxygenation. The diagnostic value of bronchial wash and sputum has been debated extensively over the years. In this study, we aim to compare the diagnostic value in several pathogens of bronchoalveolar lavage and bronchial wash, and secondarily bronchoalveolar lavage and sputum.

METHODS

We retrospectively included all adult patients in our hospital who underwent bronchoalveolar lavage, bronchial wash, and where sputum sampling was done between January 1st of 2018 and December 31st of 2021. The intraclass correlation coefficient was computed for the three tests.

RESULTS

In total, 308 patients were included. We found a level of correlation of 0.819 and 0.865, respectively, between bronchoalveolar lavage and bronchial wash for two pathogens: Staphylococcus aureus and Pseudomonas aeruginosa. For Stenotrophomonas maltophilia and Aspergillus fumigatus, we found an intraclass correlation coefficient of 0.568 and 0.624, respectively. Between bronchoalveolar lavage and sputum, we found varying levels of agreement.

CONCLUSION

Our study shows reasonably well agreement levels between bronchoalveolar lavage and bronchial wash, suggesting that bronchial wash could potentially be an alternative to bronchoalveolar lavage.

Treatable traits in advanced emphysema patients eligible for bronchoscopic lung volume reduction with endobronchial valves

INTRODUCTION

Patients with advanced emphysema eligible for bronchoscopic lung volume reduction (BLVR) using endobronchial valves (EBV) are characterized by severe static lung hyperinflation, which can be considered a treatable trait. Other treatable traits (TTs), which are assumed to be present in this highly selected patient group, have not been studied in detail nor how they may affect health-related quality of life (HRQL).

AIMS

We aimed to evaluate a spectrum of TTs in COPD patients eligible for EBV treatment and their association with HRQL.

METHODS

The SoLVE study (NCT03474471) was a prospective multicenter randomized controlled trial to examine the impact of pulmonary rehabilitation in COPD patients receiving EBV. The presence/absence of 16 TTs was based on pre-defined thresholds. HRQL was assessed with the St. George's Respiratory Questionnaire (SGRQ). Subjects were stratified into two groups, using the median split method, into higher or lower SGRQ total score. Logistic regression assessed the odds ratio (OR) of having a higher SGRQ total score per TT.

RESULTS

Ninety-seven subjects were included, the mean number of TTs per patient was 8.1 ± 2.5. Low physical activity (95%), poor exercise capacity (94%) and severe fatigue (75%) were the most prevalent TTs. The sum of TTs present in a subject was associated with the SGRQ total score (r = 0.53; p < 0.001). Severe fatigue, depression, and anxiety were predictors of having a higher SGRQ total score.

CONCLUSIONS

A high prevalence and co-occurrence of multiple TTs were identified in emphysema patients eligible for EBV. Patients with a higher number of TTs were more likely to have worse HRQL.

Lung transplant airway complications treated with biodegradable airway stents: The Dutch multi-center experience

INTRODUCTION

Treatment of post lung-transplant airway complications is challenging, and treatment with conventional airway stents is associated with adverse events. More recently, biodegradable airway stents (BDS) have been introduced and may be used to reduce these adverse events. In this study we explore the feasibility of treatment with BDS post lung transplant.

METHODS

All patients treated with BDS in The Netherlands were included in this retrospective multicenter study. Feasibility, life span of the stent, occurrence of adverse events, and evolution of lung function were evaluated.

RESULTS

Twelve patients (six malacia and six stenosis) received a total of 57 BDS, ranging from 1 to 10 BDS per patient. Six patients had been pretreated with conventional airway stents. Median stent life span was 112 days (range 66-202). No adverse events occurred during stent placement. In 5 out of 57 stent placements, a single additional bronchoscopy was necessary because of mucus accumulation (n = 4) or excessive granulation tissue (n = 1). All stent naïve patients became airway stent independent after treatment; all patients pretreated with conventional airway stents were still airway stent dependent at the end of follow up.

CONCLUSION

Treatment with BDS is safe and feasible. Adverse events were mild and easily treatable. All patients with initial treatment with BDS were airway stent independent at the end of follow up with a median treatment of 4 BDS.

Surgical and bronchoscopic pulmonary function-improving procedures in lung emphysema

COPD is a highly prevalent, chronic and irreversible obstructive airway disease without curative treatment. Standard therapeutic strategies, both non-pharmacological and pharmacological, have only limited effects on lung function parameters of patients with severe disease. Despite optimal pharmacological treatment, many patients with severe COPD still have a high burden of dyspnoea and a poor quality of life. If these patients have severe lung emphysema, with hyperinflation as the driver of symptoms and exercise intolerance, lung volume reduction may be an effective treatment with a significant impact on lung function, exercise capacity and quality of life. Currently, different lung volume reduction approaches, both surgical and bronchoscopic, have shown encouraging results and have been implemented in COPD treatment recommendations. Nevertheless, choosing the optimal lung volume reduction strategy for an individual patient remains challenging. Moreover, there is still room for improving durability of effect and safety in all available procedures. Ongoing and innovative research is essential to push this field forwards. This review provides an overview of results and limitations of the current lung volume reduction options for patients with severe lung emphysema and hyperinflation.

Impact of Endobronchial Valve Treatment on Lung Function Decline

INTRODUCTION

Endobronchial valve (EBV) treatment has been shown to be beneficial for patients with severe emphysema. The forced expiratory volume in 1 s (FEV1) was found to be significantly higher compared to baseline for up to 3 years after treatment although the magnitude of improvement gradually decreases over time. So far, it has not been investigated whether this treatment decelerates the decline in lung function. Therefore, our aim was to investigate the lung function decline before and after EBV treatment.

METHODS

We included patients who were treated with EBVs in our hospital, of whom pre-treatment spirometry results were available (at least 4 measurements within at least 2 years before treatment) and who had an annual FEV1 measurement up to 3 years after treatment.

RESULTS

In total, 45 patients were included (73% female, FEV1: 28 ± 7% of predicted, residual volume: 232 ± 32% of predicted) who had a mean pre-treatment FEV1 decline of -64 mL/year. Mean FEV1 "decline" after treatment was +13 mL/year, since FEV1 was still above the baseline level at 3-year follow-up. However, the FEV1 decline between 1 and 3 years of follow-up was not significantly different compared to the pre-treatment decline (-73 mL/year, p = 0.179).

CONCLUSIONS

Our results show that the EBV treatment does not influence the progression of disease in terms of lung function decline. However, the treatment does improve the FEV1 up to a level that is still comparable 3 years after treatment with the baseline level.

A bronchial gene signature specific for severe COPD that is retained in the nose

Introduction

A subset of COPD patients develops advanced disease with severe airflow obstruction, hyperinflation and extensive emphysema. We propose that the pathogenesis in these patients differs from mild-moderate COPD and is reflected by bronchial gene expression. The aim of the present study was to identify a unique bronchial epithelial gene signature for severe COPD patients.

Methods

We obtained RNA sequencing data from bronchial brushes from 123 ex-smokers with severe COPD, 23 with mild-moderate COPD and 23 non-COPD controls. We identified genes specific to severe COPD by comparing severe COPD to non-COPD controls, followed by removing genes that were also differentially expressed between mild-moderate COPD and non-COPD controls. Next, we performed a pathway analysis on these genes and evaluated whether this signature is retained in matched nasal brushings.

Results

We identified 219 genes uniquely differentially expressed in severe COPD. Interaction network analysis identified VEGFA and FN1 as the key genes with the most interactions. Genes were involved in extracellular matrix regulation, collagen binding and the immune response. Of interest were 10 genes (VEGFA, DCN, SPARC, COL6A2, MGP, CYR61, ANXA6, LGALS1, C1QA and C1QB) directly connected to fibronectin 1 (FN1). Most of these genes were lower expressed in severe COPD and showed the same effect in nasal brushings.

Conclusions

We found a unique severe COPD bronchial gene signature with key roles for VEGFA and FN1, which was retained in the upper airways. This supports the hypothesis that severe COPD, at least partly, comprises a different pathology and supports the potential for biomarker development based on nasal brushes in COPD.

The development, validation, and in vivo testing of a high-precision bronchial epithelial lining fluid sampling device

Introduction

Analysis of respiratory biomarkers or pharmaceutical drug concentrations in bronchial epithelial lining fluid (bELF) using a high-precision sampling method is crucial for effective clinical respiratory diagnostics and research. Here, we utilized a cellulose matrix as an absorptive probe for bELF sampling, subsequently testing the design of a device and sampling technique in vivo.

Methods

The absorptive matrix [Whatman® qualitative filter paper (Grade CF-12)] was first tested through tissue-contact experiments on porcine airway tissue. The absorption and elution capacity of the matrix, as well as the laboratory processing and analysis method, was validated with a range of Interleukin-8 (CXCL8) and C-Reactive protein (CRP) stock solutions. Subsequently, the device's design was optimized for universal in-house production and both, safe and efficient sampling. The airway sampling method was then tested in a group of 10 patients with Chronic Obstructive Pulmonary Disease (COPD). For each patient, a bELF sample was obtained using the newly developed bELF probe, as well as a reference 20 mL saline bronchial wash sample. Supernatants were assessed, using an immunoassay, for levels of the pro-inflammatory markers CXCL8, Myeloperoxidase (MPO), and CRP. The bELF samples were compared to bronchial wash.

Results

The Whatman® qualitative filter paper (Grade CF-12) bELF probes adhered to porcine airway tissue, softening slightly upon wetting. The material maintained architectural integrity following the removal of the probes, leaving no residual fibers on the porcine airway mucosa. The bELF probe design was optimized for bronchoscopic delivery and in-house production. On average, a fully saturated bELF probe carried 32 μL of protein-rich fluid. The mean return of CXCL8 and CRP from samples collected from a serial dilution series (1, 5, 10, 20 ng/mL) was 69% (range 48%-87%). The bELF probe detected, on average, 7 (MPO), 14 (CRP), and 59 (CXCL8) times higher equivalent inflammatory protein concentrations in the collected bELF probe samples compared to the bronchial wash.

Conclusion

The bELF probe is an effective absorptive technology for high-precision bELF sampling without dilution. With a simple in-house production procedure and bronchoscopic sampling technique, this method can be introduced in any bronchoscopic center for a consistent sampling of bELF.

Host-device interactions: exposure of lung epithelial cells and fibroblasts to nickel, titanium, or nitinol affect proliferation, reactive oxygen species production, and cellular signaling

Endoscopic implantation of medical devices for the treatment of lung diseases, including airway stents, unidirectional valves and coils, is readily used to treat central airway disease and emphysema. However, granulation and fibrotic tissue formation impairs treatment effectiveness. To date little is known about the interaction between implanted devices, often made from metals, such as nickel, titanium or nitinol, and cells in the airways. Here, we study the response of lung epithelial cells and fibroblasts to implant device materials. The adhesion and proliferation of bronchial epithelial cells and lung fibroblasts upon exposure to 10 × 3 × 1 mm pieces of nickel, titanium or nitinol is examined using light and scanning electron microscopy. Pro-inflammatory cytokine mRNA expression and release, signaling kinase activity and intracellular free radical production are assessed. Nitinol, and to a lesser extent nickel and titanium, surfaces support the attachment and growth of lung epithelial cells. Nitinol induces a rapid and significant alteration of kinase activity. Cells directly exposed to nickel or titanium produce free radicals, but those exposed to nitinol do not. The response of lung epithelial cells and fibroblasts depends on the metal type to which they are exposed. Nitinol induces cellular surface growth and the induction of kinase activity, while exposure of lung epithelial cells to nickel and titanium induces free radical production, but nitinol does not.

Response to endobronchial valve treatment: it's all about the target lobe

Background

Bronchoscopic lung volume reduction using endobronchial valves (EBV) has been shown to be beneficial for severe emphysema patients. The most important predictor of treatment response is absence of collateral ventilation between the treatment target and ipsilateral lobe. However, there are still a substantial number of nonresponders and it would be useful to improve the pre-treatment identification of responders. Presumably, predictors of response will be multifactorial, and therefore our aim was to explore whether we can identify response groups using a cluster analysis.

Methods

At baseline and 1 year follow-up, pulmonary function, exercise capacity and quality of life were measured. A quantitative chest computed tomography scan analysis was performed at baseline and 2-6 months follow-up. The cluster analysis was performed using a hierarchical agglomerative method.

Results

In total, 428 patients (69% female, mean±sd age 61±8 years, forced expiratory volume in 1 s 27±8% predicted, residual volume 254±50% pred) were included in our analysis. Three clusters were generated: one nonresponder cluster and two responder clusters. Despite solid technical procedures, the nonresponder cluster had significantly less clinical response after treatment compared to the other clusters. The nonresponder cluster was characterised by significantly less emphysematous destruction, less air trapping and a higher perfusion of the target lobe, and a more homogeneous distribution of emphysema and perfusion between the target and ipsilateral lobe.

Conclusions

We found that target lobe characteristics are the discriminators between responders and nonresponders, which underlines the importance of visual and quantitative assessment of the potential treatment target lobe when selecting patients for EBV treatment.

From plugging air leaks to reducing lung volume: a review of the many uses of endobronchial valves

INTRODUCTION

One-way endobronchial valve treatment improves lung function, exercise capacity, and quality of live in patients with severe emphysema and hyperinflation. Other areas of therapeutic application include treatment of persistent air leak (PAL), giant emphysematous bullae, native lung hyperinflation, hemoptysis, and tuberculosis.

AREAS COVERED

In this review, we will assess the clinical evidence and safety of the different applications of one-way endobronchial valves (EBV).

EXPERT OPINION

There is solid clinical evidence for the use of one-way EBV for lung volume reduction in emphysema. Treatment with one-way EBV can be considered for the treatment of PAL. The application of one-way EBV for giant bullae, post lung transplant native lung hyperinflation, hemoptysis, and tuberculosis is under investigation and more research is required to investigate the efficacy and safety of these applications.

The impact of emphysema heterogeneity on treatment response after endobronchial valve treatment

Background

Lung volume reduction with endobronchial valves can significantly improve functional outcomes in patients with advanced emphysema. The extent and spatial distribution pattern of emphysema shows considerable heterogeneity, which might affect response to endobronchial valve treatment. Our aim was to study the effect of emphysema heterogeneity on change in clinical outcomes after endobronchial valve treatment.

Methods

Data were collected from our national registry of patients who received endobronchial valve treatment between 2016 and 2020. We assessed the association between the heterogeneity index, absolute difference in destruction between the target and ipsilateral lobe, and relative change in forced expiratory volume in 1 s (FEV1), residual volume (RV), St George's Respiratory Questionnaire (SGRQ) and 6-min walk distance (6MWD) at 6-week, 6-month and 12-month follow-up.

Results

In total, 236 patients were included. Heterogeneity index was significantly associated with improvements in FEV1, RV and 6MWD at all follow-up visits, and in SGRQ at the 6- and 12-month follow-up visits. The majority of patients, independent of heterogeneity index, showed clinically meaningful improvements based on minimal important difference thresholds.

Conclusions

Heterogeneity index influences the degree of clinical improvement after endobronchial valve treatment where in general a more heterogeneous distribution translates to larger improvements. However, patients with a more homogeneous distribution also showed clinically meaningful improvements. Therefore, we believe emphysema heterogeneity alone should not be used as a decisive patient selection criterion, but should be weighed in the context of all other relevant patient and target lobe characteristics when deciding on a patient's treatment eligibility.

The minimal important difference of the constant work rate cycle test in severe COPD

BACKGROUND

The Constant Work Rate Cycle Test (CWRT) is a commonly used and sensitive test to detect treatment success in patients with Chronic Obstructive Pulmonary Disease (COPD). Earlier, the Minimal Important Difference (MID) of the CWRT was estimated at 101 s (or 34%) change from baseline based on one well executed study. However, this study was performed in a population of patients with mild-to-moderate COPD, and we have learned that MIDs might be quite different in patients with severe COPD. Therefore, we aimed to establish the MID of the CWRT in patients with severe COPD.

METHODS

We included 141 patients with severe COPD, who underwent either pulmonary rehabilitation, bronchoscopic lung volume reduction with endobronchial valves, or a sham bronchoscopy as a control group. CWRT workload was set at 75% of the peak work capacity, as determined by an incremental cycle test. We used the change in 6-min walking test (6-MWT), forced expiratory volume in 1s (FEV₁), residual volume (RV), and St. George's Respiratory Questionnaire (SGRQ) total score as anchors to calculate the MID.

RESULTS

All anchors had an association of ≥0.41 with change in CWRT. The MID estimates for the different anchors were: 6-MWT 278 s (95%), FEV₁ 273 s (90%), RV 240 s (84%), and SGRQ 208 s (71%). The average of these four MID estimates resulted in an MID of 250 s (or 85%).

CONCLUSION

We established the MID for CWRT at 250 s (or 85%) change from baseline in patients with severe COPD.

Endobronchial Valve Treatment Does Not Cause Significant Nickel Deposition in Lung Tissue

Bronchoscopic lung volume reduction using endobronchial valves (EBVs) is a treatment option for patients with severe emphysema. These EBVs are made out of a nitinol mesh covered by a silicone layer. Nitinol is an alloy of nickel and titanium and is commonly used in implantable medical devices because of its biocompatibility and memory-shape properties. However, there are some concerns that nickel ions can be released from nitinol-containing devices which might cause adverse health effects, especially in patients with a known nickel hypersensitivity. In vitro, it was found that EBV release significant amounts of nickel in the first hours. Our aim was to assess the nickel concentration in lung tissue from a patient who previously underwent EBV treatment but, due to treatment failure, underwent lung volume reduction surgery and to compare this to a reference sample. We found no significant difference in the median nickel concentration between the EBV-treated patient and the non-EBV-treated patient (0.270 vs. 0.328 μg/g, respectively, p = 0.693) and these concentrations were also comparable to previously published nickel concentrations in human lung tissue samples not having any medically implanted devices in the lung. Our results suggest that there is no significant long-term nickel deposition in lung tissue after EBV treatment.

[Advance care planning in COPD]

COPD (Chronic Obstructive Pulmonary Disease) affects an estimated 600,000 Dutch citizens. This chronic disease often has an unpredictable and sometimes a very invalidating course, despite various treatment options. It is important to timely initiate advance care planning in this patient population, to address any disease-related worries, needs and wishes the patient has. In this way patients (and their caregivers) can stay in the lead regarding their chronic condition, by making decisions for (future) medical, psychological, spiritual, and social needs based upon good information, their values, beliefs and experiences.

Improved exercise capacity results in a survival benefit after endobronchial valve treatment

BACKGROUND

Bronchoscopic lung volume reduction using endobronchial valves (EBV) is a treatment option for selected patients with advanced emphysema. The treatment significantly improves pulmonary function, exercise capacity, quality of life, and potentially improves survival. Our main aim was to assess whether treatment response significantly influences survival time after EBV treatment.

METHODS

We evaluated treatment response at 6-week and 1-year follow-up of all patients treated with EBVs between 2008 and 2020. Survival status was retrieved on December 1, 2021. Patients were defined as responders or non-responders based on known minimal important differences for FEV₁, residual volume (RV), RV/Total Lung Capacity (TLC) ratio, 6-min walk distance (6MWD), St. George's Respiratory Questionnaire (SGRQ), target lobe volume reduction (TLVR), and complete lobar atelectasis. Uni- and multivariate cox regression models were used to evaluate the effect of response on survival time.

RESULTS

A total of 428 patients were included. EBV treatment resulted in significant improvements in pulmonary function, exercise capacity and quality of life. Median survival was 8.2 years after treatment. SGRQ and 6MWD response were independent predictors for improved survival time (Hazard Ratio (HR) 0.50 [0.28-0.89], p = .02 and HR 0.54 [0.30-0.94], p = .03, respectively). The presence of a complete lobar atelectasis did not significantly affect survival, neither did pulmonary function improvements.

CONCLUSIONS

Our results suggest that improvement in exercise capacity and quality of life after EBV treatment are associated with a survival benefit, independent of improvements in pulmonary function, reduction in target lobe volume or the presence of complete lobar atelectasis.

The additional diagnostic value of virtual bronchoscopy navigation in patients with pulmonary nodules - The NAVIGATOR study

BACKGROUND

The number of solitary pulmonary nodules to be evaluated is expected to increase and therefore we need to improve diagnostic and therapeutic tools to approach these nodules. To prevent patients from futile invasive procedures and receiving treatment without histological confirmation of cancer, we evaluated the value of virtual bronchoscopy navigation to obtain a diagnosis of the solitary pulmonary nodule in a real-world clinical setting.

METHODS

In the NAVIGATOR single center, prospective, observational cohort study patients underwent a virtual bronchoscopy navigation procedure with or without guide sheet tunnelling to assess a solitary pulmonary nodule. Nodules were considered not accessible if a diagnosis could not be obtained by either by CT-guided transthoracic biopsy or conventional bronchoscopy.

RESULTS

Between February 2021 and January 2022 35 patients underwent the virtual bronchoscopy navigation procedure. The overall diagnostic yield was 77% and was dependent on size of the nodule and chosen path, with highest yield in lesions with an airway path. Adverse events were few and manageable.

CONCLUSION

Virtual bronchoscopy navigation with or without sheet tunnelling is a new technique with a good diagnostic yield, also in patients in whom previously performed procedures failed to establish a diagnosis and/or alternative procedures are considered not feasible based on expected yield and/or safety. Preventing futile or more invasive procedures like surgery or transthoracic punctures with a higher complication rate is beneficial for patients, and allowed treatment adaptation in two-third of the analyzed patient population.

Effect of Chest Computed Tomography Kernel Use on Emphysema Score in Severe Chronic Obstructive Pulmonary Disease Patients Evaluated for Lung Volume Reduction

BACKGROUND

Chest computed tomography (CT) emphysema quantification is a vital diagnostic tool in patient evaluation for bronchoscopic lung volume reduction (BLVR). Smooth kernels for CT image reconstruction are generally recommended for quantitative analyses. This recommendation is not always followed, which may affect quantification of emphysema extent and eventually, treatment decisions.

OBJECTIVE

The main goal is to demonstrate the influence of CT reconstruction kernels on emphysema quantification in patients with severe COPD, considered for BLVR.

METHODS

Chest CT scans were acquired with one multi-detector CT system and reconstructed using three different kernels: smooth, medium smooth, and sharp. Other parameters were kept constant. Emphysema scores (ESs), meaning the percentage of voxels below -950 Hounsfield units, were calculated and compared to the smooth reference kernel using paired t tests. Bland-Altman plots were made to assess the biases and limits of agreement between kernels.

RESULTS

Ninety-eight COPD patient CT scans were analyzed. The sharp kernel had a systematic bias of 6.2% and limits of agreement of 16.6% to -4.2% compared to the smooth kernel. The medium smooth kernel had a systematic bias of 5.7% and limits of agreement of 9.2% and 2.2% compared to the smooth kernel. The ES differed, for a single patient, up to 18% for different kernels.

CONCLUSIONS

Chest CT kernel reconstruction can lead to a significant difference in emphysema severity quantification. This may cause invalid treatment selection in COPD patients evaluated for BLVR. Standardization of a smooth CT kernel setting and/or normalization to a standard kernel is strongly recommended.

Bronchoscopic Lung Volume Reduction in Patients with Emphysema due to Alpha-1 Antitrypsin Deficiency

BACKGROUND

Bronchoscopic lung volume reduction using one-way endobronchial valves (EBVs) is a valid therapy for severe emphysema patients. However, alpha-1 antitrypsin (AAT)-deficient patients were excluded from the majority of clinical trials investigating this intervention.

OBJECTIVES

The aim of this study was to investigate the feasibility, efficacy, and safety of EBV treatment in patients with AAT deficiency (AATD) or a reduced AAT level.

METHOD

A retrospective analysis was performed of all patients treated with EBV with confirmed AATD or with a reduced AAT serum level at the University Medical Center Groningen between 2013 and 2021. Baseline and 6-month follow-up assessment included chest CT, pulmonary function measurement, 6-min walking distance (6MWD), and St. George's Respiratory Questionnaire (SGRQ).

RESULTS

In total, 53 patients were included, 30 patients in the AATD group (AAT <0.6 g/L or confirmed ZZ phenotype) and 23 patients in the reduced AAT group (AAT 0.6-1 g/L). In both groups, all response variables improved significantly after treatment. There was a median increase in forced expiratory volume in 1 s of 105 mL (12% relative) and 280 mL (31% relative) in the AATD and reduced AAT groups, respectively. 6MWD increased by 62 min and 52 min, and SGRQ decreased by 12.5 patients and 18.7 patients, respectively. A pneumothorax occurred in 10% and 13% of patients, and no patients died.

CONCLUSIONS

EBV treatment in patients with emphysema and AATD or a reduced AAT level is feasible and results in significant improvements in pulmonary function, exercise capacity, and quality of life and has an acceptable safety profile.

Computed tomographic airway morphology after targeted lung denervation treatment in COPD

This post-hoc analysis of the AIRFLOW-2 trial investigated the changes in airway CT-parameters after targeted lung denervation (TLD) and whether these changes are associated with treatment response. In the treatment group (n = 32), an improvement in air trapping was significantly associated with an improvement in residual volume (RV). Furthermore, improvements in Pi10 and airway lumen were significantly associated with an improvement in both RV and FEV₁. Our results could suggest that when improving airway characteristics like decreasing airway wall thickness and increasing the airway lumen, this leads to less air trapping and an improvement in clinical outcomes.

Prevalence and Impact of COVID-19 among Severe COPD Patients post Bronchoscopic Lung Volume Reduction Treatment with Endobronchial Valves

BACKGROUND

The COVID-19 pandemic has a great impact on numberless aspects of our society. In our bronchoscopic lung volume reduction interventional program, we work with severe COPD patients on a daily basis.

OBJECTIVES

We were interested in the prevalence and outcome of COVID-19, impact of the pandemic on daily life, and the vaccination coverage in our severe COPD patients who have been treated with one-way endobronchial valves.

METHOD

A questionnaire, which consisted of questions related to the infection rate, treatment, and outcome of COVID-19 infections; feelings of anxiety related to the pandemic; adherence to preventive measures; and willingness to be vaccinated; was sent to our patients in June 2021.

RESULTS

The questionnaire was sent to 215 patients, and the response rate was 100%. The vaccination rate was 97% in our surveyed population. The majority of patients (63%) indicated that they were quite or very anxious to get infected with COVID-19. Twenty-five (11.5%) patients were diagnosed with COVID-19, with none of these patients having been vaccinated at the time of infection. The infection rate reported in this study is comparable to that of the general Dutch population. However, the hospital admission rate and mortality rates are higher.

CONCLUSIONS

Our results show that the SARS-CoV-2 infection rate in severe COPD patients treated with endobronchial valves was comparable with the general population; however, the hospital admission and mortality rates were worse.

Targeted lung denervation modulates the mucosal epithelial transcriptome in COPD

This study shows that TLD reduces airway epithelial expression of genes related to acetylcholine processing and airway inflammation, which may help to elucidate the mechanism for its effect of reducing severe exacerbations in COPD https://bit.ly/3dWcqZk.

Safety and Considerations of the Anaesthetic Management during Bronchoscopic Lung Volume Reduction Treatments

BACKGROUND

Different bronchoscopic lung volume reduction approaches are available for a select group of patients with advanced COPD. General anaesthesia is the recommended method of sedation during these procedures. However, this patient population is at an increased risk of anaesthetic complications, and the best approach to general anaesthesia and mechanical ventilation is unknown.

OBJECTIVES

The aims of this study were to describe the anaesthetic management techniques used during bronchoscopic lung volume reduction procedures and to investigate the number of anaesthesia-related events.

METHODS

Data were retrospectively collected from all endobronchial valve and lung volume reduction coil procedures performed between January 2018 and March 2020 in our hospital. Primary outcomes measures were anaesthetic technique including airway management; ventilation mode and settings; and the incidence of anaesthesia-related events, classified as catastrophic, severe, significant, or moderate.

RESULTS

202 procedures were included. One procedure was performed under procedural sedation, 198 (98%) under general anaesthesia with endotracheal intubation, and 3 (1.5%) under general anaesthesia with laryngeal mask airway. Volume-controlled ventilation was used in 64% of the procedures and pressure-controlled in 36%. Patients were ventilated with a median respiration rate of 9.9 (IQR: 9.6-10.6) breaths per minute, mean tidal volume of 5.8 ± 1.4 mL/kg, and median inspiratory to expiratory (I:E) ratio of 1:2.8 (IQR: 1:2.1-1:3.2). No catastrophic anaesthesia-related events were observed. Hypotension was the most observed anaesthesia-related event.

CONCLUSIONS

Despite the presence of advanced COPD, general anaesthesia and mechanical ventilation are well tolerated by patients undergoing endobronchial valve or lung volume reduction coil treatment. This is presumably strongly linked to the strict selection criteria. Other important considerations are using a low respiratory rate, low tidal volume, and high I:E ratio.

Crossover Patient Outcomes for Targeted Lung Denervation in Moderate to Severe Chronic Obstructive Pulmonary Disease: AIRFLOW-2

BACKGROUND

Targeted Lung Denervation (TLD) is a potential new therapy for COPD. Radiofrequency energy is bronchoscopically delivered to the airways to disrupt pulmonary parasympathetic nerves, to reduce bronchoconstriction, mucus hypersecretion, and bronchial hyperreactivity.

OBJECTIVES

This work assesses the effect of TLD on COPD exacerbations (AECOPD) in crossover subjects in the AIRFLOW-2 trial.

METHOD

The AIRFLOW-2 trial is a multicentre, randomized, double-blind, sham-controlled crossover trial of TLD in COPD. Patients with symptomatic COPD on optimal medical therapy with an FEV1 of 30-60% predicted received either TLD or sham bronchoscopy in a 1:1 randomization. Those in the sham arm had the opportunity to cross into the treatment arm after 12 months. The primary end point was rate of respiratory adverse events. Secondary end points included adverse events, changes in lung function and health-related quality of life and symptom scores.

RESULTS

Twenty patients were treated with TLD in the crossover phase and were subsequently followed up for 12 months (50% female, mean age 64.1 ± 6.9 years). After TLD, there was a trend towards a reduction in time to first AECOPD (hazard ratio 0.65, p = 0.28, not statistically significant) in comparison to sham follow-up period. There was also a reduction in time to first severe AECOPD in the crossover period (hazard ratio 0.38, p = 0.227, not statistically significant). Symptom scores and lung function showed stability.

CONCLUSIONS

AIRFLOW-2 crossover data support that of the randomization phase, showing trends towards reduction in COPD exacerbations with TLD.

From Differential DNA Methylation in COPD to Mitochondria: Regulation of AHRR Expression Affects Airway Epithelial Response to Cigarette Smoke

Cigarette smoking causes hypomethylation of the gene Aryl Hydrocarbon Receptor Repressor (AHRR), which regulates detoxification and oxidative stress-responses. We investigated whether AHRR DNA methylation is related to chronic obstructive pulmonary disease (COPD) and studied its function in airway epithelial cells (AECs). The association with COPD was assessed in blood from never and current smokers with/without COPD, and in AECs from ex-smoking non-COPD controls and GOLD stage II-IV COPD patients cultured with/without cigarette smoke extract (CSE). The effect of CRISPR/Cas9-induced AHRR knockout on proliferation, CSE-induced mitochondrial membrane potential and apoptosis/necrosis in human bronchial epithelial 16HBE cells was studied. In blood, DNA methylation of AHRR at cg05575921 and cg21161138 was lower in smoking COPD subjects than smoking controls. In vitro, AHRR DNA methylation at these CpG-sites was lower in COPD-derived than control-derived AECs only upon CSE exposure. Upon AHRR knockout, we found a lower proliferation rate at baseline, stronger CSE-induced decrease in mitochondrial membrane potential, and higher CSE-induced late apoptosis/necroptosis. Together, our results show lower DNA methylation of AHRR upon smoking in COPD patients compared to non-COPD controls. Our data suggest that higher airway epithelial AHRR expression may lead to impaired cigarette smoke-induced mitochondrial dysfunction and apoptosis/necroptosis, potentially promoting unprogrammed/immunogenic cell death.

Long term follow up after bronchoscopic lung volume reduction valve treatment for emphysema

Background

Multiple studies have shown that patients with severe emphysema can significantly benefit from the bronchoscopic lung volume reduction treatment with endobronchial valves (EBV) up to 1 year after treatment. However, hardly any data exists on longer term follow-up, especially on quality of life. Our aim was to investigate the long term follow-up after EBV treatment up to 3 years including quality of life in a real life routine clinical setting.

Methods

We retrospectively included patients who underwent EBV treatment in our hospital at least 3 years ago. Patients were invited for annual visits to our hospital and spirometry, bodyplethysmography, 6-min walk distance test (6 MWD) and SGRQ-questionnaire were performed during these visits.

Results

At one, two and three years of follow-up, data was available from 189, 146 and 112 patients, respectively. FEV1, RV and SGRQ total score significantly improved as compared to baseline up to 3 years after treatment and 6MWD up to 2 years. In general, the magnitude of the improvements gradually decreased over time.

Conclusion

Our results show that patients can benefit at least up to three years after the EBV treatment. For the first time we found that patients can also benefit in terms of quality of life in the long term which is an important outcome for these group of patients with end-stage COPD.

Long-Term Follow-Up of Intralobar Bullae After Endobronchial Valve Treatment for Emphysema

Endoscopic lung volume reduction using unidirectional endobronchial valves is a new technique in the treatment of patients with severe emphysema. However, the movements of the thoracic structures after endobronchial valves insertion are still unpredictable We report the unusual outcome of six patients after valves insertion in the left upper lobe. They all developed a complete atelectasis of the target lobe, a pneumothorax and sequential genuine bullae in the treated left lung of unknown etiology. The chest CT scan prior to the valves insertion was unremarkable. Three patients developed an air–liquid level in the bullae the day before a bacterial infection of their left lower lobe. The three other patients had an uneventful spontaneous resolution of their bullae at long-term follow-up. Therefore, a conservative attitude should be followed in this particular setting.

Reduction of Lung Hyperinflation Improves Cardiac Preload, Contractility, and Output in Emphysema: A Prospective Cardiac Magnetic Resonance Study in Patients Who Received Endobronchial Valves

RATIONALE

Pulmonary hyperinflation in patients with Chronic Obstructive Pulmonary Disease (COPD) has been related to smaller cardiac chamber sizes and impaired cardiac function. Nowadays, bronchoscopic lung volume reduction (BLVR) with endobronchial valves is a treatment option to reduce pulmonary hyperinflation in patients with severe emphysema.

OBJECTIVES

We hypothesized that reduction of hyperinflation would improve cardiac preload in this patient group. In addition, we investigated whether the treatment would result in elevated pulmonary artery pressures due to pulmonary vascular bed reduction.

METHODS

We included patients with emphysema and severe hyperinflation (defined by a baseline residual volume >175% of predicted) who were eligible for BLVR with endobronchial valves. Cardiac magnetic resonance imaging was obtained one day prior to treatment and at eight week follow-up. Primary endpoint was cardiac preload, as measured by the right ventricle end-diastolic volume index (RVEDVI). As secondary endpoints, we measured indexed end-diastolic and end-systolic volumes of the right ventricle, left atrium, and left ventricle, pulmonary artery pressures, cardiac output, ejection fraction, and strain.

MEASUREMENTS AND MAIN RESULTS

Twenty-four patients were included. At eight week follow-up, RVEDVI was significantly improved (+7.9 ml/m2, SD 10.0, p=0.001). In addition to increased stroke volumes, we found significantly higher ejection fractions and strain measurements. Although cardiac output was significantly increased (+0.9L/min, SD 1.5, p=0.007), there were no changes in pulmonary artery pressures.

CONCLUSIONS

We found that reduction of hyperinflation using BLVR with endobronchial valves significantly improved cardiac preload, myocardial contractility, and cardiac output, without changes in pulmonary artery pressures. Clinical trial registered with ClinicalTrials.gov (NCT03474471).

Bronchoscopic Lung Volume Reduction for Emphysema: Review and Update

In carefully selected patients with severe chronic obstructive pulmonary disease, characterized by emphysema and hyperinflation, lung volume reduction is an option to reduce lung hyperinflation, improve lung function, quality of life, and exercise capacity. Currently, there are several bronchoscopic and surgical treatment options to achieve lung volume reduction. It is important to carefully phenotype these patients, to select the optimal treatment option, with consideration of possible adverse events or contraindications, and it is highly recommended to discuss these treatment strategies in a multidisciplinary team. The treatment with one-way endobronchial valves has been investigated most extensively and more data are available regarding the treatment of more "marginal cases," or subsequent lung volume reduction surgery. Other bronchoscopic lung volume reduction options include treatment with coils, thermal vapor ablation, and sclerosant agents. In this review, we aim to summarize the current clinical evidence on the bronchoscopic lung volume reduction therapies and important aspects regarding optimal patient selection.

Bronchoscopic Lung Volume Reduction Coil Treatment for Severe Emphysema: A Systematic Review and Meta-Analysis of Individual Participant Data

Background

Lung volume reduction coil (LVR-coil) treatment provides a minimally invasive treatment option for severe emphysema patients which has been studied in multiple clinical trials.

Objectives

The aim of the study was to assess the effect of LVR-coil treatment on pulmonary function, quality of life, and exercise capacity using individual participant data.

Method

PubMed, Web of Science, and EMBASE were searched until May 17, 2021. Prospective single-arm and randomized controlled trials that evaluated the effect of LVR-coil treatment on forced expiratory volume in 1 s (FEV₁), residual volume (RV), St. George Respiratory Questionnaire (SGRQ) total score, and/or 6-min walk distance (6MWD) and were registered in an official clinical trial database were eligible for inclusion. Individual patient data were requested, and a linear mixed effects model was used to calculate overall treatment effects.

Results

Eight trials were included in the final analysis, representing 680 individual patients. LVR-coil treatment resulted in a significant improvement in FEV1 at 3- (0.09 L [95% confidence interval (95% CI): 0.06–0.12]) and 6-month follow-up (0.07 L [95% CI: 0.03–0.10]), a significant reduction in RV at 3- (−0.45L [95% CI: −0.62 to −0.28]), 6- (−0.33L [95% CI: −0.52 to −0.14]), and 12-month follow-up (−0.36L [95% CI: −0.64 to −0.08]), a significant reduction in SGRQ total score at 3- (−12.3 points [95% CI: −15.8 to −8.8]), 6- (−10.1 points [95% CI: −12.8 to −7.3]), and 12-month follow-up (−9.8 points [95% CI: −15.0 to −4.7]) and a significant increase in 6MWD at 3-month follow-up (38 m [95% CI: 18–58]).

Conclusions

LVR-coil treatment in emphysema patients results in sustained improvements in pulmonary function and quality of life and shorter lived improvements in exercise capacity. Since the owner of this LVR-coil has decided to stop the production and newer generations LVR-coils are currently being developed, these results can act as a reference for future studies and clinical guidance.

Identification of damage associated molecular patterns and extracellular matrix proteins as major constituents of the surface proteome of lung implantable silicone/nitinol devices

Lung implantable devices have been widely adopted as mechanical interventions for a wide variety of pulmonary pathologies. Despite successful initial treatment, long-term efficacy can often be impacted by fibrotic or granulation tissue formation at the implant sites. This study aimed to explore the lung-device interface by identifying the adhered proteome on lung devices explanted from patients with severe emphysema. In this study, scanning electron microscopy is used to visualize the adhesion of cells and proteins to silicone and nitinol surfaces of explanted endobronchial valves. By applying high-resolution mass-spectrometry, the surface proteome of eight explanted valves is characterized, identifying 263 unique protein species to be mutually adsorbed on the valves. This subset is subjected to gene enrichment analysis, matched with known databases and further validated using immunohistochemistry. Enrichment analyses reveal dominant clusters of functionally-related ontology terms associated with coagulation, pattern recognition receptor signaling, immune responses, cytoskeleton organization, cell adhesion and migration. Matching results show that extracellular matrix proteins and damage-associated molecular patterns are cardinal in the formation of the surface proteome. This is the first study investigating the composition of the adhered proteome on explanted lung devices, setting the groundwork for hypothesis generation and further exploration. STATEMENT OF SIGNIFICANCE: This is the first study investigating the composition of the adhered proteome on explanted lung devices. Lung implantable devices have been widely adopted as mechanical interventions for pulmonary pathologies. Despite successful initial treatment, long-term efficacy can often be impacted by fibrotic or granulation tissue formation around the implant sites. We identified the adhered proteome on explanted lung devices using several techniques. We identified 263 unique protein species to be mutually adsorbed on explanted lung devices. Pathway analyses revealed that these proteins are associated with coagulation, pattern recognition receptor signaling, immune responses, cytoskeleton organization, cell adhesion and migration. Furthermore, we identified that especially extracellular matrix proteins and damage-associated molecular patterns were cardinal in the formation of the surface proteome.

[Is it difficult-to-treat asthma? Or another diagnosis?]

BACKGROUND

When suspected of difficult-to-treat asthma, it is important to detect causal factors. Central airway malignancy should also be excluded in this group.

CASE DESCRIPTION

We describe the case of a 23-year-old woman who came to the emergency room for shortness of breath and was subsequently admitted to the intensive care unit for respiratory failure, indicated by an asthma exacerbation. At an outpatient visit for dyspnea complaints, now with a stridor on physical examination, a chest CT was performed, which showed an occlusive lesion. Bronchoscopy turned out to be an endobronchial tumor. PA showed that it was a primary pulmonary myxoid sarcoma.

CONCLUSION

The case above shows why it is important to consider rare pathologies, such as a central airway tumor, in asthma that is difficult to treat. A thorough history and physical examination is an important first step, especially the presence of a stridor.

Crosslink bio-adhesives for bronchoscopic lung volume reduction: current status and future direction

Several bronchoscopic lung volume reduction (BLVR) treatments have been developed to reduce hyperinflation in emphysema patients. Lung bio-adhesives are among the most promising new BLVR treatment options, as they potentially provide a permanent solution for emphysematous patients after only a single application. To date, bio-adhesives have mainly been used as haemostats and tissue sealants, while their application in permanently contracting and sealing hyperinflated lung tissue has recently been identified as a novel and enticing opportunity. However, a major drawback of the current adhesive technology is the induction of severe inflammatory responses and adverse events upon administration. In our review, we distinguish between and discuss various natural, semi-synthetic and synthetic tissue haemostats and sealants that have been used for pulmonary applications such as sealing air/fluid leaks. Furthermore, we present an overview of the different materials including AeriSeal and autologous blood that have been used to achieve lung volume reduction and discuss their respective advantages and drawbacks. In conclusion, we describe the key biological (therapeutic benefit and biocompatibility) and biomechanical (degradability, adhesive strength, stiffness, viscoelasticity, tunability and self-healing capacity) characteristics that are essential for an ideal lung bio-adhesive material with the potential to overcome the concerns related to current adhesives.

Evaluation of spirometry-gated computed tomography to measure lung volumes in emphysema patients

Introduction

In emphysema patient being evaluated for bronchoscopic lung volume reduction (BLVR), accurate measurement of lung volumes is important. Total lung capacity (TLC) and residual volume (RV) are commonly measured by body plethysmography but can also be derived from chest computed tomography (CT). Spirometry-gated CT scanning potentially improves the agreement of CT and body plethysmography. The aim of this study was to compare lung volumes derived from spirometry-gated CT and “breath-hold-coached” CT to the reference standard: body plethysmography.

Methods

In this single-centre retrospective cohort study, emphysema patients being evaluated for BLVR underwent body plethysmography, inspiration (TLC) and expiration (RV) CT scan with spirometer guidance (“gated group”) or with breath-hold-coaching (“non-gated group”). Quantitative analysis was used to calculate lung volumes from the CT.

Results

200 patients were included in the study (mean±sd age 62±8 years, forced expiratory flow in 1 s 29.2±8.7%, TLC 7.50±1.46 L, RV 4.54±1.07 L). The mean±sd CT-derived TLC was 280±340 mL lower compared to body plethysmography in the gated group (n=100), and 590±430 mL lower for the non-gated group (n=100) (both p<0.001). The mean±sd CT-derived RV was 300±470 mL higher in the gated group and 700±720 mL higher in the non-gated group (both p<0.001). Pearson correlation factors were 0.947 for TLC gated, 0.917 for TLC non-gated, 0.823 for RV gated, 0.693 for RV non-gated, 0.539 for %RV/TLC gated and 0.204 for %RV/TLC non-gated. The differences between the gated and non-gated CT results for TLC and RV were significant for all measurements (p<0.001).

Conclusion

In severe COPD patients with emphysema, CT-derived lung volumes are strongly correlated to body plethysmography lung volumes, and especially for RV, more accurate when using spirometry gating.

The cellular composition of the lung lining fluid gradually changes from bronchus to alveolus

Although large advances have recently been made mapping out the cellular composition of lung tissue using single cell sequencing, the composition and distribution of the cellular elements within the lining fluid of the lung has not been extensively studied. Here, we assessed the cellular composition of the lung lining fluid by performing a differential cell analysis on bronchoalveolar lavage fluid (BALF) and epithelial lining fluid (ELF) at four different locations within the lung in post-lung transplantation patients. The percentage of neutrophils and lymphocytes is reduced in more distal regions of the lungs, while the percentage of macrophages increases in these more distal regions. These data provide valuable information to determine which lung lining fluid sampling technique and location is best to use for measuring specific factors and biomarkers, and to increase the understanding of different cell populations in specific lung regions.

Bronchoscopic Targeted Lung Denervation in Patients with Severe Asthma: Preliminary Findings

Treatment options for severe asthma are limited, particularly in those patients who do not meet criteria for biologicals. Targeted lung denervation (TLD) is the bronchoscopic ablation of the peribronchial vagal nerve trunks to reduce cholinergic stimulation of airway smooth muscle and submucosal glands. This report describes the experience of the first 2 asthma patients treated with TLD worldwide. The participants were 54 and 51 years of age, and both had severe asthma (GINA 5) (FEV1: 53% and 113% of predicted; AQLQ scores: 5.3 and 4.4). Both participants were treated with TLD in a single day-case procedure under general anaesthesia. Lung function, health status, and adverse event data were collected at baseline and 12 months after TLD. No treatment-related serious adverse events were reported up to 12 months. Cough symptoms improved in both participants, and 1 participant reported a marked reduction in rescue medication use at 6 months. There were no significant changes in spirometry, lung volumes, or health status. In conclusion, TLD was performed safely in both participants, but more evidence is needed to clarify safety and efficacy of TLD in severe asthma. Therefore, further investigation of the treatment in severe asthma patients would be useful.

Dual-Energy Computed Tomography Compared to Lung Perfusion Scintigraphy to Assess Pulmonary Perfusion in Patients Screened for Endoscopic Lung Volume Reduction

BACKGROUND

Endoscopic lung volume reduction (ELVR) using one-way endobronchial valves is a technique to reduce hyperinflation in patients with severe emphysema by inducing collapse of a severely destroyed pulmonary lobe. Patient selection is mainly based on evaluation of emphysema severity on high-resolution computed tomography and evaluation of lung perfusion with perfusion scintigraphy. Dual-energy contrast-enhanced CT scans may be useful for perfusion assessment in emphysema but has not been compared against perfusion scintigraphy.

AIMS

The aim of the study was to compare perfusion distribution assessed with dual-energy contrast-enhanced computed tomography and perfusion scintigraphy.

MATERIAL AND METHODS

Forty consecutive patients with severe emphysema, who were screened for ELVR, were included. Perfusion was assessed with 99mTc perfusion scintigraphy and using the iodine map calculated from the dual-energy contrast-enhanced CT scans. Perfusion distribution was calculated as usually for the upper, middle, and lower thirds of both lungs with the planar technique and the iodine overlay.

RESULTS

Perfusion distribution between the right and left lung showed good correlation (r = 0.8). The limits of agreement of the mean absolute difference in percentage perfusion per region of interest were 0.75-5.6%. The upper lobes showed more severe perfusion reduction than the lower lobes. Mean difference in measured pulmonary perfusion ranged from -2.8% to 2.3%. Lower limit of agreement ranged from -8.9% to 4.6% and upper limit was 3.3-10.0%.

CONCLUSION

Quantification of perfusion distribution using planar 99mTc perfusion scintigraphy and iodine overlays calculated from dual-energy contrast-enhanced CTs correlates well with acceptable variability.

Airway granulation response to lung-implantable medical devices: a concise overview

Increasing numbers of endoscopically implantable devices are implanted in the airways, such as airway stents, one-way valves and coils, to treat both malignant and benign diseases. They significantly improve patient outcomes, but their long-term effectiveness and sustainability is hampered by the reaction of the formation of granulation tissue. Factors including procedural-related tissue injury; micro-organism presence; device-related factors, such as the material, design and sizing in relation to the airway; and patient-related factors, including genetic susceptibility, comorbidities and medication use, might all effect the severity of the tissue response and the subsequent degree of granulation tissue formation. However, research into the underlying mechanism and risk factors is scarce and therefore our knowledge is limited. Joint efforts from the scientific community, both pre-clinical and clinical, are needed to gain a deeper understanding and eventually improve the long-term treatment effectiveness of lung-implantable devices.

Medical implantable devices are increasingly used in pulmonary medicine. Complications related to the tissue–device interaction are often present, but our knowledge of the underlying processes is limited.https://bit.ly/2RdWVkG

An adjusted and time-saving method to measure collateral ventilation with Chartis

Introduction

Bronchoscopic lung volume reduction with endobronchial valves is an important treatment option in selected patients with severe emphysema and absence of collateral ventilation in the treatment target lobe. The Chartis system provides an important physiological assessment of the presence or absence of collateral ventilation. We aimed to evaluate a new feature and determine whether low flow during a Chartis measurement is predictive for the absence of collateral ventilation, and whether this allows for a procedure to be shortened by earlier terminating the Chartis measurement. This is measured with the “volume trend for the previous 20 s” (VT20).

Methods

We retrospectively evaluated 249 Chartis assessments of patients scheduled for bronchoscopic lung volume reduction procedures. The VT20 was calculated, and several thresholds were compared between patients with collateral ventilation (CV positive) and without collateral ventilation (CV negative).

Results

100% of the CV negative patients reached a threshold of VT20 ≤6 mL, whereas all CV positive patients reached a VT20 ≥7 mL. The median “time saved” between VT20=6 mL and end of assessment was 60 s (range 5–354 s).

Conclusion

The threshold of VT20 ≤6 mL is a reliable method to exclude the presence of collateral ventilation when air flow rates are low and can therefore reduce bronchoscopic lung volume procedure times.

The volume trend for the previous 20 s (VT20) is an adjusted method of the Chartis measurement. This feature helps to interpret the Chartis measurement more easily and it effectively shortens the Chartis assessment time, especially in cases with low flow.https://bit.ly/3wlClxv

Biodegradable stent placement for airway kinking after bronchoscopic lung volume reduction treatment

Symptomatic airway kinking after bronchoscopic lung volume reduction with endobronchial valves is rare. Due to the development of the desired lobar atelectasis, the position of the airways of the non-treated lobe changes and this might lead to invalidating symptoms. We present a case of a patient with symptomatic airway kinking after treatment with endobronchial valves, who was successfully treated with a single placement of a biodegradable stent. Placement of a biodegradable stent can be considered in symptomatic patients with airway kinking.