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.

Endobronchial coils for emphysema: Dual mechanism of action on lobar residual volume reduction

BACKGROUND AND OBJECTIVE

The RENEW trial demonstrated that bronchoscopic lung volume reduction using endobronchial coils improves quality of life, pulmonary function and exercise performance. In this post hoc analysis of RENEW, we examine the mechanism of action of endobronchial coils that drives improvement in clinical outcomes.

METHODS

A total of 78 patients from the RENEW coil-treated group who were treated in one or both lobes that were deemed as the most destroyed were included in this retrospective analysis. Expiratory and inspiratory HRCT scans were used to assess lobar volume change from baseline to 12 months post coil treatment in treated and untreated lobes.

RESULTS

Reduction in lobar RV in treated lobes was significantly associated with favourable clinical improvement. Independent predictor of the change in RV and FEV₁ was the change in lobar RV reduction in the treated lobes and for change in 6MWD the absence of cardiac disease and the change in SGRQ, while the independent predictor of change in SGRQ was the change in 6MWD.

CONCLUSION

Our results suggest that residual lobar volume reduction in treated lobes measured by QCT is the driving mechanism of action of endobronchial coils leading to positive clinical outcomes. However, the improvement in exercise capacity and quality of life seems to be affected by the presence of cardiac disease.

Predictors of Response to Endobronchial Coil Therapy in Patients With Advanced Emphysema

BACKGROUND

The Lung Volume Reduction Coil Treatment in Patients With Emphysema (RENEW) trial reported improvements in quality of life, pulmonary function, and exercise performance following endobronchial coil treatment.

OBJECTIVES

The purpose of this post hoc analysis was to identify baseline predictors, including quantitative CT measures, that identify patients most likely to significantly benefit from endobronchial coil therapy.

METHODS

Quantitative CT analysis by an independent radiology laboratory and a qualitative evaluation by five blinded experts of the baseline thoracic CT imaging were performed. Univariate and multivariate logistic regression analyses were performed to elucidate characteristics associated with clinical response.

RESULTS

In total, 125 patients underwent coil treatment and had evaluable 12-month follow-up results. Of these, 78 patients received treatment of lobes with the highest emphysematous destruction determined by quantitative CT analysis (quantitative visual match [QVM]+), and 47 received treatment in at least one lobe that was not the most destroyed (QVM-). From the 78 patients with QVM+ treatment, a subgroup of 50 patients (64%) was identified with baseline residual volume > 200% predicted, emphysema score > 20% low attenuation area, and absence of airway disease. In this subgroup, greater lobar residual volume reduction in the treated lobes was achieved, which was associated with significant mean ± SE improvement in FEV₁ (15.2 ± 3.1%), St. George's Respiratory Questionnaire (-12 ± 2 points), and residual volume (-0.57 ± 0.13 L).

DISCUSSION

This post hoc analysis found that both significant hyperinflation (residual volume ≥ 200% predicted) and CT analysis are critical for patient selection and treatment planning for endobronchial coil therapy. Quantitative CT analysis is important to identify optimal lobar treatment and to exclude patients with insufficient emphysema (< 20% low attenuation area), whereas visual assessment identifies patients with signs of airway disease associated with worse outcomes.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01608490; URL: www.clinicaltrials.gov.

History of lung volume reduction procedures

Lung volume reduction (LVR) procedures for emphysematous patients were firstly introduced in the second half of the twentieth century. Over time, from the first invasive surgical procedures, new less invasive techniques have been conceived. In regards to the surgical approach, the adoption of VATS and the execution, in selected centers, of a non-resectional approach, with folding of less functional lung tissue, reduced mortality and adverse events risks. As regards to the bronchoscopic approach, endobronchial valves (EBV) and intrabronchial valves (IBV) were initially proposed in the early 2000s to obtain segmental or lobar atelectasis of the more compromised lung parenchyma. Despite showing promising results with respect to improvement of pulmonary function tests, particularly forced expiratory volume in 1st second (FEV₁), and quality of life, and a good safety profile, valves showed disappointing results in presence of collateral ventilation, such as in cases of incomplete fissures. To overcome this technical issue, in the last 10 years, endobronchial coils have been designed and used. Having a compressive effect on the lung parenchyma where they are located, they are not affected by collateral ventilation. Randomized control trials (RCTs) on endobronchial coils showed a significant improvement in FEV₁ and quality of life, however this technique was not immune to side effects, particularly low respiratory tract infections and pneumothoraces. Besides bronchial valves (BV) and coils, airway by-pass stents have also been evaluated in a RCT but without reaching the desired endpoints. Other innovative procedures recently considered and delivered through bronchoscopy regards thermal energy, with vapour therapy, to achieve a scarring reaction of the emphysematous lung parenchyma, and polymeric foams used as lung sealants to achieve absorptive atelectasis. In conclusion, LVR procedures may be considered in carefully selected patients with symptomatic emphysema and severe lung hyperinflation, and might be personalized according to the anatomical characteristics of emphysematous area.

Clinical and quantitative computed tomography predictors of response to endobronchial lung volume reduction therapy using coils

Objectives

Bronchoscopic lung volume reduction using coils (LVRC) is a well-known treatment option for severe emphysema. The purpose of this study was to identify quantitative computed tomography (QCT) and clinical parameters associated with positive treatment outcome.

Patients and methods

The CT scans, pulmonary function tests (PFT), and 6-minute walk test (6-MWT) data were collected from 72 patients with advanced emphysema prior to and at 3 months after LVRC treatment. The procedure involved placing 10 coils unilaterally. Various QCT parameters were derived using Apollo imaging software (VIDA). Independent predictors of clinically relevant outcome (Δ6-MWT ≥ 26 m, ΔFEV₁ ≥ 12%, ΔRV ≥ 10%) were identified through stepwise linear regression analysis.

Results

The response outcome for Δ6-MWT, for ΔFEV₁ and for ΔRV was met by 55%, 32% and 42%, respectively. For Δ6-MWT ≥ 26 m a lower baseline 6-MWT (p = 0.0003) and a larger standard deviation (SD) of low attenuation cluster (LAC) sizes in peripheral regions of treated lung (p = 0.0037) were significantly associated with positive outcome. For ΔFEV₁ ≥ 12%, lower baseline FEV₁ (p = 0.02) and larger median LAC sizes in the central regions of treated lobe (p = 0.0018) were significant predictors of good response. For ΔRV ≥ 10% a greater baseline TLC (p = 0.0014) and a larger SD of LAC sizes in peripheral regions of treated lung (p = 0.007) tended to respond better.

Conclusion

Patients with lower FEV₁ and 6-MWT, with higher TLC and specific QCT characteristics responded more positively to LVRC treatment, suggesting a more targeted CT-based approach to patient selection could lead to greater efficacy in treatment response.

Bronchoscopic lung volume reduction: recent updates

Emphysema causes significant morbidity and mortality, incurring both financial and psychosocial costs. Alternatives to medical therapy and surgical lung volume reduction surgery (LVRS) have increased interest in bronchoscopic techniques. Bronchoscopic lung volume reduction (BLVR) is still in its infancy and additional trials and follow-up are critical. However, several new randomized clinical trials (RCTs) have demonstrated improvement in lung function, quality of life and exercise capacity in select patients receiving endobronchial valves and coil therapy. This article highlights recent data regarding bronchoscopic treatment of emphysema.

Efficacy and safety of bronchoscopic lung volume reduction therapy in patients with severe emphysema: a meta-analysis of randomized controlled trials

BACKGROUND

Increasing randomized controlled trials (RCTs) indicate that bronchoscopic lung volume reduction (BLVR) is effective for severe emphysema. In this meta-analysis, we investigated the efficacy and safety of BLVR in patients with severe emphysema.

METHODS

PubMed, Embase and the Cochrane Library and reference lists of related articles were searched, and RCTs that evaluated BLVR therapy VS conventional therapy were included. Meta-analysis was performed only when included RCTs ≥ 2 trials.

RESULTS

In total, 3 RCTs for endobronchial coils, 6 RCTs for endobronchial valves (EBV) and 2 RCTs for intrabronchial valves (IBV) were included. Compared with conventional therapy, endobronchial coils showed better response in minimal clinically important difference (MCID) for forced expiratory volume in 1s (FEV1) (RR = 2.37, 95% CI = 1.61 - 3.48, p < 0.0001), for 6-min walk test (6MWT) (RR = 2.05, 95% CI = 1.18 - 3.53, p = 0.01), and for St. George's Respiratory Questionnaire (SGRQ) (RR = 2.32, 95% CI = 1.77 - 3.03, p < 0.00001). EBV therapy also reached clinically significant improvement in FEV1 (RR = 2.96, 95% CI = 1.49 - 5.87, p = 0.002), in 6MWT (RR = 2.90, 95% CI = 1.24 - 6.79, p = 0.01), and in SGRQ (RR = 1.53, 95% CI = 1.22 - 1.92, p = 0.0002). Both coils and EBV treatment achieved statistically significant absolute change in FEV1, 6MWT, and SGRQ from baseline, also accompanied by serious adverse effects. Furthermore, subgroup analysis showed there was no difference between homogeneous and heterogeneous emphysema in coils group. However, IBV group failed to show superior to conventional group.

CONCLUSIONS

Current meta-analysis indicates that coils or EBV treatment could significantly improve pulmonary function, exercise capacity, and quality of life compared with conventional therapy. Coils treatment could be applied in homogeneous emphysema, but further trials are needed.

Successful Late Removal of Endobronchial Coils

Although endobronchial coils for the treatment of severe emphysema are associated with an acceptable safety profile, adverse events such as pneumothorax and thoracic pain may occur. The coils are indicated as a permanent implant and are deemed very difficult to remove. We describe the first successful removal of two coils 10 months after placement in a patient who experienced persistent thoracic pain. This case report highlights that very distal (subpleural) coil placement may induce pneumothorax and subsequent thoracic pain and that nonsurgical removal of coils up to 10 months after implantation is feasible.

Interventional Options for COPD- LVRS, Bronchoscopic Therapies and the Future

This article serves as aCME available, enduring material summary of the following COPD9_USA presentations: "Lung Volume Reduction Surgery" Presenter: William A. Bulman, MD "Bronchoscopic Approaches to Lung Volume Reduction" Presenter: Frank Sciurba, MD "Stem Cell Therapies for Advanced Emphysema" Presenter: Edward P. Ingenito, MD, PhD "Lung Transplantation for COPD" Presenter: Daniel Dilling, MD, FACP, FCCP.