Bronchoscopic interventions for severe emphysema: Where are we now?

First real-time imaging of bronchoscopic lung volume reduction by electrical impedance tomography

BACKGROUND

Bronchoscopic lung volume reduction (BLVR) with one-way endobronchial valves (EBV) has better outcomes when the target lobe has poor collateral ventilation, resulting in complete lobe atelectasis. High-inspired oxygen fraction (FIO2) promotes atelectasis through faster gas absorption after airway occlusion, but its application during BLVR with EBV has been poorly understood. We aimed to investigate the real-time effects of FIO2 on regional lung volumes and regional ventilation/perfusion by electrical impedance tomography (EIT) during BLVR with EBV.

METHODS

Six piglets were submitted to left lower lobe occlusion by a balloon-catheter and EBV valves with FIO2 0.5 and 1.0. Regional end-expiratory lung impedances (EELI) and regional ventilation/perfusion were monitored. Local pocket pressure measurements were obtained (balloon occlusion method). One animal underwent simultaneous acquisitions of computed tomography (CT) and EIT. Regions-of-interest (ROIs) were right and left hemithoraces.

RESULTS

Following balloon occlusion, a steep decrease in left ROI-EELI with FIO2 1.0 occurred, 3-fold greater than with 0.5 (p < 0.001). Higher FIO2 also enhanced the final volume reduction (ROI-EELI) achieved by each valve (p < 0.01). CT analysis confirmed the denser atelectasis and greater volume reduction achieved by higher FIO2 (1.0) during balloon occlusion or during valve placement. CT and pocket pressure data agreed well with EIT findings, indicating greater strain redistribution with higher FIO2.

CONCLUSIONS

EIT demonstrated in real-time a faster and more complete volume reduction in the occluded lung regions under high FIO2 (1.0), as compared to 0.5. Immediate changes in the ventilation and perfusion of ipsilateral non-target lung regions were also detected, providing better estimates of the full impact of each valve in place.

TRIAL REGISTRATION

Not applicable.

Endobronchial valve treatment in chronic obstructive pulmonary disease: A qualitative study of patients' expectations

Objectives

Endobronchial valve (EBV) treatment is a treatment option for selected patients with severe chronic obstructive pulmonary disease (COPD) to reduce dyspnea and improve quality of life. However, the procedure is associated with risk of complications, and not all patients achieve the expected outcomes. The present study explores patients' expectations while waiting for EBV treatment.

Methods

Fifteen patients accepted for EBV treatment at Aarhus University Hospital in Denmark from October 2020 to June 2021 participated in a 30-min, semi-structured interview about (1) the experience of living with COPD and (2) expectations regarding EBV.

Results

Four themes were identified: a life of reduced quality; hopes and expectations; information about EBV; and perception of risks. Most patients described their lives as not worth living, and they hoped that EBV would give them their physical and social lives back, while also being aware that EBV would probably not work miracles. Patients' information seeking was influenced by their hopes and expectations to the treatment. They filtered out negative information, focusing on the hope for a positive outcome. This made them willing to run the risk of complications.

Conclusion

Living a life of considerably reduced quality, patients might have an increased focus on potential positive effects of EBV treatment while filtering out information about potential side effects. This might bias their decision-making process.

Assessment of efficacy and safety of endoscopic lung volume reduction with one-way valves in patients with a very low FEV1

Introduction

Endoscopic lung volume reduction (ELVR) with one-way valves produces beneficial outcomes in patients with severe emphysema. Evidence on the efficacy remains unclear in patients with a very low forced expiratory volume in 1 s (FEV1) (≤20% predicted). We aim to compare clinical outcomes of ELVR, in relation to the FEV1 restriction.

Methods

All data originated from the German Lung Emphysema Registry (Lungenemphysem Register), which is a prospective multicentric observational study for patients with severe emphysema after lung volume reduction. Two groups were formed at baseline: FEV1 ≤20% pred and FEV1 21-45% pred. Pulmonary function tests (FEV1, residual volume, partial pressure of carbon dioxide), training capacity (6-min walk distance (6MWD)), quality of life (modified Medical Research Council dyspnoea scale (mMRC), COPD Assessment Test (CAT), St George's Respiratory Questionnaire (SGRQ)) and adverse events were assessed and compared at baseline and after 3 and 6 months.

Results

33 patients with FEV1 ≤20% pred and 265 patients with FEV1 21-45% pred were analysed. After ELVR, an increase in FEV1 was observed in both groups (both p<0.001). The mMRC and CAT scores, and 6MWD improved in both groups (all p<0.05). The SGRQ score improved significantly in the FEV1 21-45% pred group, and by trend in the FEV1 ≤20% pred group. Pneumothorax was the most frequent complication within the first 90 days in both groups (FEV1 ≤20% pred: 7.7% versus FEV1 21-45% pred: 22.1%; p=0.624). No deaths occurred in the FEV1 ≤20% pred group up to 6 months.

Conclusion

Our study highlights the potential efficacy of one-way valves, even in patients with very low FEV1, as these patients experienced significant improvements in FEV1, 6MWD and quality of life. No death was reported, suggesting a good safety profile, even in these high-risk patients.

Endoscopic Lung Volume Reduction with One-Way Valves in Patients with Severe Chronic Obstructive Pulmonary Disease with Hypercapnia

BACKGROUND

Robust clinical evidence on the efficacy and safety of endoscopic lung volume reduction (ELVR) with one-way valves in patients with severe lung emphysema with chronic hypercapnic respiratory failure is lacking.

OBJECTIVE

The aim of this study was to compare patient characteristics, clinical outcome measures, and incidences of adverse events between patients with severe COPD undergoing ELVR with one-way valves and with either a partial pressure of carbon dioxide (pCO2) of ≤45 mm Hg or with pCO2 >45 mm Hg.

METHODS

This was a multicentre prospective study of patients with severe lung disease who were evaluated based on lung function, exercise capacity (6-min walk test [6-MWT]), and quality-of-life tests.

RESULTS

Patients with pCO2 ≤45 mm Hg (n = 157) and pCO2 >45 mm Hg (n = 40) showed similar baseline characteristics. Patients with pCO2 ≤45 mm Hg demonstrated a significant increase in forced expiratory volume in 1 s (p < 0.001), a significant decrease in residual volume (RV) (p < 0.001), and significant improvements in the quality of life and 6-MWT at the 3-month follow-up. Patients with pCO2 >45 mm Hg had significant improvements in RV only (p < 0.05). There was a significant decrease in pCO2 between baseline and follow-up in hypercapnic patients, relative to the decrease in patients with pCO2 ≤45 mm Hg (p = 0.008). Patients who were more hypercapnic at baseline showed a greater reduction in pCO2 after valve placement (r = -0.38, p < 0.001). Pneumothorax was the most common adverse event in both groups.

CONCLUSIONS

ELVR with one-way valves seems clinically beneficial with a remarkably good safety profile for patients with chronic hypercapnic respiratory failure.

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.

Expeditious Resolution of Giant Bullae with Endobronchial Valves and Percutaneous Catheter Insertion

As bullae contribute to decreased lung function in chronic obstructive pulmonary disease (COPD) patients, effective decompression of large bullae is important. Bronchoscopic lung volume reduction via endobronchial one-way valves is less invasive and has a lower mortality rate than lung volume reduction surgery. We report the case of a 48-year-old male who presented with giant bullae that were expeditiously resolved with endobronchial valves and percutaneous catheter insertion. Three days later, imaging revealed marked decreases in the extent of bullae and atelectasis of the contralateral lung without any complications, including air leakage or pneumothorax. Combination of endobronchial valves and percutaneous catheter insertion might be helpful to accelerate the release of large bullae and to achieve improved lung function and higher levels of physical activity in patients with COPD.

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.

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

Endoscopic lung volume reduction with endobronchial valves in very low D LCO patients: results from the German Registry - Lungenemphysemregister e.V

Background

Endoscopic lung volume reduction (ELVR) with valves has been suggested to be the key strategy for patients with severe emphysema and concomitant low diffusing capacity of the lung for carbon monoxide (D_LCO). However, robust evidence is still missing. We therefore aim to compare clinical outcomes in relation to D_LCO for patients treated with ELVR.

Methods

We assessed D_LCO at baseline and 3 months follow-up and compared pre- and postprocedural pulmonary function test, quality of life, exercise capacity and adverse events. This is a retrospective subanalysis of prospectively collected data from the German Lung Emphysema Registry.

Results

In total, 121 patients treated with ELVR were analysed. Thirty-four patients with a D_LCO ≤20% and 87 patients with a D_LCO >20% showed similar baseline characteristics. After ELVR, there was a decrease of residual volume (both p<0.001 to baseline) in both groups, and both demonstrated better quality of life (p<0.01 to baseline). Forced expiratory volume in 1 s (FEV₁) improved significantly only in patients with a D_LCO >20% (p<0.001 to baseline). Exercise capacity remained almost unchanged in both groups (p=0.3). The most frequent complication for both groups was a pneumothorax (D_LCO ≤20%: 17.6% versus D_LCO >20%: 16.1%; p=0.728). However, there were no significant differences in other adverse events between both groups.

Conclusions

ELVR improves lung function as well as quality of life in patients with D_LCO >20% and D_LCO ≤20%. Adverse events did not differ between groups. Therefore, ELVR should be considered as a treatment option, even in patients with a very low D_LCO.

Endoscopic lung volume reduction with endobronchial valves can be safely performed in patients with a very low diffusing capacity of the lung (D_LCO). Clinical effectiveness is comparable to patients with higher D_LCO.https://bit.ly/3cOgDK1

Endobronchial Valves for the Treatment of Advanced Emphysema

Bronchoscopic lung volume reduction with one-way endobronchial valves is a guideline treatment option for patients with advanced emphysema that is supported by extensive scientific data. Patients limited by severe hyperinflation, with a suitable emphysema treatment target lobe and with absence of collateral ventilation, are the responders to this treatment. Detailed patient selection, a professional treatment performance, and dedicated follow up of the valve treatment, including management of complications, are key ingredients to success. This treatment does not stand alone; it especially requires extensive knowledge of COPD for which the most appropriate treatment is discussed in a multidisciplinary approach. We discuss the endobronchial valve treatment for emphysema and provide a guideline for patient selection, treatment guidance, and practice tools, based on our own experience and literature.

Endobronchial valve therapy for severe emphysema: an overview of valve-related complications and its management

INTRODUCTION

Bronchoscopic lung volume reduction treatment with one-way valves is an effective guideline treatment option for patients with severe emphysema. However, important challenges and adverse reactions may occur after treatment.

AREAS COVERED

This review summarizes the complications after endobronchial and intrabronchial valve treatment that have been described by the currently published randomized controlled trials and other relevant papers regarding the complications and its management. In case there was no relevant literature regarding these subjects, recommendations are based on expert opinion. Complications include pneumothorax, post-obstruction pneumonia and hemoptysis. Also, the treatment may not be effective due to the presence of collateral ventilation or misplaced valves. Furthermore, an initial beneficial effect may vanish due to granulation tissue formation, valve dysfunction or valve migration. Careful follow-up after treatment with valves is important. Evaluation with a CT-scan and/or bronchoscopy is needed if there is no improvement after treatment, loss of benefit, or occurrence of important adverse events during follow-up.

EXPERT OPINION

Treating severe emphysema patients with one-way valves requires continuous dedication and expertise, especially to achieve an optimal outcome and elegantly deal with the various complications after treatment.