Two-year follow-up after endobronchial coil treatment in emphysema: results from the REVOLENS study

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.

Which Endoscopic Procedure to Use and in What Patient? Valves, Coils, Foam, and Heat in COPD and Asthma

Despite the latest developments in therapeutic agents targeting airway endotypes, a significant proportion of patients with asthma and chronic obstructive pulmonary disease (COPD) remain symptomatic. Endoscopic therapies have a complementary role in the management of these airway diseases. The sustained efficacy of bronchial thermoplasty (BT) among patients with asthma over 10 years has been encouraging, as it has been shown to improve symptom control and reduce hospital admissions and exacerbations. Studies suggest that BT helps ameliorate airway inflammation and reduce airway smooth muscle thickness. While studies suggest that it is as effective as biologic agents, its role in the management of severe asthma has yet to be clearly defined and GINA 2022 still suggests limiting its use to patients with characteristics of the various populations studied. Conversely, bronchoscopic lung volume reduction has shown promise among patients with advanced COPD. Rigorous patient selection is important. Patients with minimal collateral ventilation (CV) and higher heterogeneity index have shown to benefit the most from endobronchial valve (EBV) therapy. For those with ongoing CV, endobronchial coils would be more appropriate. Both therapeutic modalities have demonstrated improved quality of life, effort tolerance, and lung function indices among appropriately selected patients. The emerging evidence suggests that endoscopic procedures among airway disease still have a substantial role to play despite the development of new therapeutic options.

Effect of Endobronchial Coils on Exercise Tolerance and Lung Functions in Patients with Severe Emphysema - A Retrospective Cohort Study of 48 Patients

Background

Lung volume reduction with endobronchial coils treatment (ECT), for patients with severe emphysema, has shown modest improvement in exercise capacity and lung functions in clinical trials, yet the benefit of this procedure is still unclear.

Methods

We conducted a multicenter retrospective cohort study including all patients who underwent ECT in Israel and a propensity score matched control group of patients with chronic obstructive pulmonary disease (COPD) that were treated with usual care. The primary outcome was six-minute walk test distance (6MWTD), secondary outcomes were lung function tests and patient survival.

Results

Overall, 46 patients were included in the ECT group. Their mean 6MWTD at baseline and at 6 and at 24 months post procedure was 331.0±101.4, 372.9±76.8 and 338.8±104.8, respectively (overall P=0.04, pairwise comparison: baseline to 6 months (P=0.1), baseline to 24 months (P=1.0)). Mean FEV1 values at baseline and at 6 and at 24 months post procedure were 0.86±0.38, 0.92±0.37 and 0.82±0.36 liters, respectively (overall P=0.003, pairwise comparison: baseline to 6 months (P=0.04), baseline to 24 months (P=0.75)). The median 6MWTD for the ECT and control groups at 24 months were 333.0 (262.5–390) and 280 (210–405), respectively (P=0.16). There was no difference in overall survival (P=0.84). Heterogenous emphysema was a significant predictor of treatment success in univariate analysis (p=0.004).

Conclusion

Lung volume reduction with endobronchial coils may improve the exercise capacity and FEV1 of COPD patients. However, the majority of the effect was diminished after 24 months. The current state of evidence does not support regulatory approval of ECT and warrant its use only after consideration of the benefit-harm ratio in a highly selected patient population.

Future Treatment of Emphysema with Roles for Valves, Novel Strategies and Lung Volume Reduction Surgery

Although there are multiple pharmacologic and nonpharmacological options to alleviate symptoms of emphysema, none of these treatment modalities halts disease progression. The expanding disease burden has led to development of innovative therapeutic strategies that also aim to induce lung volume reduction. Bronchoscopic lung volume reduction originated in 2001 and has continued to grow rapidly ever since. This article discusses more recent developments in bronchoscopic and novel interventions and speculates on how these novel strategies may impact the future of lung reduction interventions.

Bronchoscopic management of asthma, COPD and emphysema

In recent years, many bronchoscopic techniques have been developed in chronic obstructive airway inflammatory diseases, including asthma, COPD and emphysema. The main techniques with available data from randomised controlled trials are: 1) bronchial thermoplasty in asthma; 2) valves, coils and thermal vapor ablation in emphysema; and 3) targeted lung denervation in COPD. The objectives of this article are to describe the levels of evidence for efficacy and safety, long-term follow-up results beyond 1 year, and current recommendations for clinical practice from international guidelines for each technique.

Bronchoscopic interventions for emphysema: Current status

Chronic obstructive pulmonary disease is a prevalent and progressive disease. The recently developed bronchoscopic lung volume reduction (BLVR) techniques offer personalized therapeutic options in subgroups of patients with severe emphysema. Endobronchial and intrabronchial valves (EBV/IBV) achieve lung volume reduction by lobar atelectasis. The lung volume reduction coils (LVRCs) and bronchoscopic thermal vapor ablation (BTVA) induce tissue compression, either mechanically or through inflammatory processes. While the effects of EBV/IBV are reversible by removing the implants, the effects of LVRC are partially reversible and that of BTVA is irreversible. The presence of interlobar collateral ventilation (CV) impacts on EBV/IBV treatment outcome due to its mechanism of action. Therefore, using radiological and endoscopic techniques to assess CV has a vital importance. Current evidence of BLVR demonstrates acceptable safety and short-term clinical efficacy. However, head-to-head trials are lacking, and further research is needed to establish long-term clinical benefit, durability, and cost-effectiveness of these techniques.

Lung Volume Reduction in Pulmonary Emphysema

Severe emphysema with hyperinflation presents a therapeutic challenge. Inhaled medication has limited efficacy in individuals with mechanical constraints to the respiratory pump and impaired gas exchange. Lung volume reduction surgery (LVRS) reestablishes some semblance of normal physiology, resecting grossly expanded severely diseased tissue to restore the function of compromised relatively healthy lung, and has been shown to significantly improve exercise capacity, quality of life, and survival, especially in individuals with upper-lobe predominant emphysema and low-baseline exercise capacity, albeit with higher early morbidity and mortality. Bronchoscopic lung volume reduction achieved by deflating nonfunctioning parts of the lung is promoted as a less invasive and safer approach. Endobronchial valve implantation has demonstrated comparable outcomes to LVRS in selected individuals and has recently received approvals by the National Institute of Clinical Excellence in the United Kingdom and the Food and Drug Administration in the United States of America. Endobronchial coils are proving a viable treatment option in severe hyperinflation in the presence of collateral ventilation in selected cases of homogeneous disease. Modalities including vapor and sealant are delivered using a segmental strategy preserving healthier tissue within the same target lobe-efficacy and safety-data are, however, limited. This article will review the data supporting these novel technologies.

Bronchoscopic interventions for severe emphysema: Where are we now?

Patients with severe emphysema have limited treatment options and only derive a small benefit from optimal medical treatment. The only other therapy to have significant clinical beneficial effect in emphysema is LVRS but the perceived risk and invasiveness of surgery has fuelled bronchoscopic approaches to induce lung volume reduction. There are multiple bronchoscopic methods for achieving volume reduction in severe emphysema: EBV, airway bypass procedure, endobronchial coils, thermal (vapour) sclerosis and chemical sclerosis (sealants). Optimal patient selection is key to successful patient outcomes. This review discusses bronchoscopic approaches for emphysema treatment which has progressed through clinical trials to clinical practice.

Protocol of a Randomized Controlled Study of the PneumRx Endobronchial Coil System versus Standard-of-Care Medical Management in the Treatment of Subjects with Severe Emphysema (ELEVATE)

BACKGROUND

The PneumRx endobronchial coil system for patients with severe emphysema has been shown to improve quality of life, exercise capacity, and pulmonary function in patients with emphysema. A post hoc analysis of the RENEW trial has identified patient characteristics and lobar selection methods associated with improved outcomes, which have to be confirmed prospectively.

METHODS

The ELEVATE trial is a prospective, multicenter, open label, randomized (2:1), controlled trial comparing outcomes in patients treated with endobronchial coils (treatment) to a medically managed control group (control). The trial aims to enroll 210 patients (140 in the treatment group and 70 in the control group) with severe emphysema. Control patients will be eligible to crossover to coil treatment after 6 months of follow-up. The co-primary effectiveness endpoints are percent change in forced expiratory volume in 1 s and quality of life measured by change in St. George's Respiratory Questionnaire from baseline to 6 months. Secondary objectives are determination of responder rates of clinical endpoints and mean change in other functional and physiologic endpoints. All patients will be followed for 24 months after initial treatment. Adverse events will be collected on an ongoing basis throughout the trial.

DISCUSSION

The primary objective of the ELEVATE trial is to prospectively confirm the safety and effectiveness profile of the coil system for the treatment of severe emphysema in consideration of the findings of previous randomized controlled trials. Secondary objectives are the determination of responder rates in all clinical endpoints and mean change in physiologic endpoints.

Importance of bronchoscopic lung volume reduction coil therapy in potential candidates for lung transplantation

Bronchoscopic lung volume reduction (BLVR) coil treatment is a alternative and promising treatment modality for selected severe emphysema patients. The main indication of this treatment modality is a forced expiration volume in one second (FEV1) of 15-45% and a residual volume (RV) > 175%. The aim of this study was to investigate the efficacy of BLVR coil therapy in patients with end-stage emphysema who were potential candidates for lung transplantation and had FEV1 values less than 25%. Twenty-one patients who underwent bilateral BLVR coil therapy between September 2013 and May 2015 were retrospectively reviewed. We compared the changes in clinical and laboratory parameters at the baseline and 12 months after the treatment. Twelve months after the bilateral BLVR coil treatment, we observed an average increase in FEV1 (110 mL and 4.6%), a decrease in residual volume (660 mL and 33%), and an increase in 6-minute walk tests (67 m). The most common complications were chronic obstructive pulmonary disease exacerbation (47.6%) and pneumonia (23.8%). All patients tolerated the general anesthesia and procedure very well. BLVR coil therapy is safe and effective in patients with end-stage emphysema, who are potential candidates for lung transplantation within a short to medium period. The complication rates of this treatment were not different from those of the other coil treatments, and the improvements in the clinical parameters after the treatment resulted in gaining time for lung transplantation. Future research for evaluating the long-term efficacy of BLVR coil therapy in these patients is essential.