Endoscopic lung volume reduction coils for patients with severe emphysema—a single-centre retrospective analysis

Abstract

 

OBJECTIVES

Patients with chronic obstructive pulmonary disease and lung emphysema may benefit from surgical or endoscopic lung volume reduction (ELVR). Previously reported outcomes of nitinol coil-based ELVR techniques have been ambiguous. The analysis was done to analyse outcomes of ELVR with nitinol coils in patients with severe pulmonary emphysema.

METHODS

From September 2013 to November 2014, our centre performed a total of 41 coil implantations on 29 patients with severe emphysema. Coils were bronchoscopically placed during general anaesthesia. Twelve out of 29 patients received staged contralateral treatments up to 112 days later to avoid bilateral pneumothorax. Lung function and 6-min walking distance were assessed 1 week prior, 1 week after as well as 6–12 months after the procedure. Patients were followed up to 48 months after ELVR and overall mortality was compared to a historic cohort.

RESULTS

While coil-based ELVR led to significant short-term improvement of vital capacity (VC, +0.14 ± 0.39 l, P = 0.032) and hyperinflation (Δ residual volume/total lung capacity −2.32% ± 6.24%, P = 0.022), no significant changes were observed in 6-min walking distance or forced expiratory volume in 1 s. Benefits were short-lived, with only 15.4% and 14.3% of patients showing sustained improvements in forced expiratory volume in 1 s or residual volume after 6 months. Adverse events included haemoptysis (40%) and pneumothorax (3.4%), major complications occurred in 6.9% of cases. Overall survival without lung transplant was 63.8% after 48 months following ELVR, differing insignificantly from what BODE indices of patients would have predicted as median 4-year survival (57%) at the time of ELVR treatment.

CONCLUSIONS

ELVR with coils can achieve small and short-lived benefits in lung function at the cost of major complications in a highly morbid cohort. Treatment failed to improve 4-year overall survival. ELVR coils are not worthwhile the risk for most patients with severe emphysema.

INTRODUCTION

The health burden of chronic obstructive pulmonary disease (COPD) is increasing world-wide [1–3]. COPD pathogenesis is triggered mostly be inhaled irritants, e.g. tobacco smoke, causing airway remodelling and consecutive obstruction. Progressive air trapping leads to the development of emphysema, further deteriorating ventilatory mechanics in COPD patients [4].

Pharmacologic treatments alone are often insufficient to palliate symptoms and terminate the downwards spiral of dyspnoea and inactivity in emphysema patients. The idea of lung volume reduction surgery (LVRS) as a treatment for advanced emphysema was first described more than 60 years ago [5]. The high early postoperative mortality initially prevented a widespread clinical acceptance of LVRS despite encouraging results. Advantages in perioperative intensive care unit treatment and surgical techniques enabled Cooper and colleagues [6] to reintroduce and refine the procedure in 1995. The most comprehensive study evaluating LVRS was the National Emphysema Treatment Trial (NETT) including 1218 patients with severe emphysema [7]. This prospective randomized controlled multicentre trial compared optimal medical treatment with optimal medical treatment plus LVRS. The NETT showed a survival advantage for patients with predominantly upper-lobe emphysema and low baseline exercise capacity and improvement of health status and exercise capacity but not survival for those with high post-rehabilitation exercise capacity [7]. To reduce the supposedly high morbidity and mortality associated with LVRS, endoscopic techniques were more and more used and studied. Both, surgical and endoscopic lung volume reduction (ELVR), apart from lung transplantation, have been proven effective in improving exercise capacity and quality of life [7, 8]. However, data about long-term outcome are still rare. ELVR procedures are appealing to many patients due to the seemingly less invasive nature compared to open surgery. Basically, 2 ELVR treatment modalities are mainly used, endobronchial valves (EBV) and coils. Coils are memory-shaped nitinol implants, deployed endoscopically in emphysematous areas of the lung. ELVR using endobronchial coils have been shown to improve exercise tolerance, quality of life and lung function as compared to optimal medical therapy [9–11]. Since the introduction of ELVR techniques into clinical routine, our centre has collected extensive experience performing both valve- and coil-based ELVR procedures. The aims of this analysis were 2-fold:

1. to investigate short- and long-term effects of ELVR on lung function, exercise capacity and all-cause mortality and

2. to assess the safety of ELVR by implantation of nitinol coils in patients with advanced emphysema in a real-word setting.

METHODS

Ethics approval and consent to participate

The necessity for informed consent was waived for the retrospective, anonymous analysis and publication of the data by the local ethics committee (Ärztekammer des Saarlandes). Patients gave written informed consent for the intervention.

From September 2013 to November 2014, 29 patients received a total of 41 ELVR coil implantations. All patients had COPD in advanced stage (spirometrically Global Initiative for Chronic Obstructive Lung Disease; GOLD III or IV) and considerable symptoms despite optimal medical therapy. All patients were screened prior to ELVR by lung function testing and 6-min walking distance (6-MWD) test. Chest computer tomography (CT) and ventilation/perfusion (V/Q) scans were analysed by the interdisciplinary emphysema board (comprising of consultants in radiology/thoracic surgery/pneumology) to analyse emphysema distribution and to select target lung lobes suitable for coil placement. The emphysema treatment centre has access to intensive care unit beds and extracorporeal lung support at all times.

After patients gave informed consent for the intervention, bronchoscopy and periprocedural preparations were performed according to our internal standard. Nitinol coils were obtained from PneumRX, Inc., Santa Monica, CA, USA. The interventionalist placed the bronchoscope at the ostium of the target subsegmental airway, a catheter was then advanced to measure the distance to the pleura, and the most appropriate coil length (100, 125 or 150 mm) based on subsegmental airway length was chosen. Once loaded into the application cartridge, the implanter advanced the coil into the target airway. The endobronchial coil returned to its original shape once fully deployed, thus coiling up the surrounding airway and tensioning the adjacent parenchyma. The goal was to place a minimum of 10 endobronchial coils in the target lobe to achieve maximum lung tissue decompression. Coil deployment was done under fluoroscopic guidance. Twelve out of 29 patients underwent a second procedure on the contralateral side after up to 112 days later in the same fashion. Patients were hospitalized for 1–3 days after coil implantation and discharged when their clinical state was stable. The patients were regularly reassessed on every visit at our outpatient clinic.

Statistical analysis of patient lung function parameters and 6-MWDs was performed with SPSS (IBM SPSS Statistics 26) using 2-sided t-testing. We did not correct for multiple testing for the different hypotheses tested. BODE indices at the time of ELVR treatment were calculated for each patient as proposed by Celli et al. [12]. Data on overall survival 48 months after ELVR was collected and Kaplan–Meier plots were compared to survival data of Celli et al.’s [12] historic COPD cohort from 2003. Kaplan–Meier plots were generated using the software Prism 5 (GraphPad Software, San Diego, CA, USA). We did not correct for multiple testing.

To exclude that failure to improve a patient’s clinical condition was due to misjudgement of the investigator as to which lung lobe should be selected for coil placement, patient chest CT scans were submitted to 2 independent commercial providers of CT analysis software and analyses were compared to interventionalist’s decision. Program A was provided by PneumRX GmbH (Düsseldorf, Germany), program B was provided by PulmonX (Redwood City, CA, USA). Program A was not deemed specific for coil implantation but was developed rather for the deployment of EBV.

RESULTS

The patients had a median age of 63.8 years, 65.5% of them were male. Average forced expiratory volume in 1 s (FEV₁) was 0.77 ± 0.3 l before ELVR, mean 6-MWD was 255.5 ± 142.8 m. All patients had relevant emphysema on their chest CT scan and showed elevated fraction of RV/total lung capacity (TLC) (mean 71.5% ± 8.1%) in lung function testing. Six of the 29 patients had previously received EBV for ELVR, as they had a target lobe according to CT and V/Q-scan without collateral ventilation. Lung function improved slightly after EBV for most patients (mean Δ forced vital capacity +0.18 l, P = 0.4, mean ΔFEV₁ + 0.14 l, P = 0.049, mean ΔRV −0.41 l, P = 0.32). There was no overall improvement in RV/TLC (mean Δ −0.3%, P = 0.94). Except for 1 patient, all others had minor improvements in 6-MWD (mean Δ +31 m, P = 0.3) up to 3 months after EBV implantation. The median time from EBV treatment to coil implantation was 210 days (IQ-range 231 days). Table 1 provides an overview of patient baseline characteristics.

Table 1:

Baseline characteristics and pre-interventional lung function test results from all 29 patients included in the study cohort.

General characteristics
Median age (years)	63.8
Male	19 (65.6%)
Female	10 (34.4%)
Height (m)	1.68 ± 0.095
Weight (kg)	67.9 ± 17.35
BMI (kg/m²)	23.8 ± 4.98
Previous lung volume reduction treatment
Endobronchial valves	6
Endobronchial coils	0
Lung function parameters
FEV1 (l)	0.77 ± 0.31
FEV1 (% of predicted)	28.85 ± 9.76
FVC (l)	1.84 ± 0.58
FVC (% of predicted)	55.42 ± 15.30
TLC (l)	7.76 ± 1.30
TLC (% of predicted)	132.32 ± 26.01
RV (l)	5.58 ± 1.26
RV (% of predicted)	249.55 ± 65.60
RV/TLC (%)	71.52 ± 8.07
RAWtot (kPa*s/l)	7.40 ± 4.01
sRAWtot (kPa*s)	5.89 ± 2.70
6-min walk test (m)	292.91 ± 89.56
DLCO (ml/min/kPa)	2.28 ± 1.08
DLCO (% of predicted)	26.9% ± 11.8%

BMI: body mass index; FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity; RAW_tot: measured airway resistance; RV: residual volume; sRAW_tot: specific airway resistance; TLC: total lung capacity.

Twelve out of 29 patients underwent a second implantation of coils on the contralateral side. Contralateral coils were offered whenever CT scans showed possible target lobes on the other side and V/Q scans revealed no relevant side difference in ventilation or perfusion. The interval between procedures varied between 28 and 112 days (mean 77 ± 26 days), giving patients enough time to recover.

Between 8 and 12 coils were implanted in a single lobe in 1 session (average 10.3), most frequently in the right upper lobe (62.1%), followed by the left upper lobe (21.4%). During the second ELVR, the left upper lobe was chosen most frequently (50%) followed by the right upper lobe (25%). The lower lobes were targeted in 13.7% of cases during the first and 25% during the second procedure. The middle lobe was completely neglected.

Two of 29 patients had major complications. Limited haemoptysis was observed relatively frequently following ELVR (40%), 1 patient required interventional bronchoscopy and intensive care treatment for relevant bleeding. Another patient developed unilateral pneumothorax, which required drainage. Post-interventional pneumonia was not observed. All 29 patients recovered and could be discharged. The frequency of acute exacerbation following ELVR was not recorded.

First and second ELVR (if performed) taken together, coil implantation led to limited short-term improvements in lung function. There was no difference in FEV₁ measurable (average increase of 0.04 ± 0.19 l, P = 0.21). Inspiratory vital capacity (VC_in) increased significantly only when first and second intervention were taken into account (increase on average 0.14 ± 0.39 l, P = 0.032), A significant decrease in RV/TLC was detectable after the first ELVR (mean Δ −2.32% ± 6.24%, P = 0.022). The 6-MWD following ELVR did not change significantly (mean Δ −14.03 ± 73.52 m, P = 0.27). Patients had to take the same number of breaks during testing (mean of 0.76). Baseline DLCO in the general study population was 2.24 ± 1.08 ml/min/kPa, equalling 26.9% of normal. Altogether, lung volume reduction coils led to a small and insignificant increase in DLCO (2.24 ml/min/kPa equalling 26.9% of normal vs 2.34 ml/min/kPa equalling 27.5% of normal, P = 0.78). The amount of oxygen supplementation during exercise did not change (mean Δ 0.25 ± 1.14 l/min, P = 0.21) (Table 2). Regarding only the second ELVR procedure alone, no relevant improvement of either lung function parameters or 6-MWD were detectable.

Table 2:

Lung functional assessment of short-term effects of ELVR coils in 29 patients with severe emphysema 4–6 weeks after first coil treatment (n = 41 measurements)

	Before	After	Mean Δ	P-value
FEV1 (l)	0.77 ± 0.31	0.81 ± 0.31	+0.04 ± 0.19	0.21
FEV1 (% of pr.)	28.85 ± 9.76	30.71 ± 10.73	+1.86 ± 6.92	0.093
FVC (l)	1.84 ± 0.58	1.94 ± 0.61	+0.10 ± 0.40	0.12
FVC (% of pr.)	55.42 ± 15.30	58.89 ± 16.56	+3.46 ± 12.58	0.086
VCin	2.16 ± 0.73	2.29 ± 0.61	+0.14 ± 0.39	0.032
VCin (% of pr.)	63.22 ± 17.75	66.56 ± 16.68	+3.35 ± 10.95	0.061
RV (l)	5.58 ± 1.26	5.28 ± 1.45	−0.30 ± 1.27	0.14
RV (% of pr.)	249.55 ± 65.60	233.34 ± 57.67	−16.21 ± 54.69	0.065
RV/TLC (%)	71.53 ± 8.07	69.21 ± 7.96	−2.32 ± 6.24	0.022
SRtot (% of pr.)	687.88 ± 409.17	612.77 ± 313.70	−75.11 ± 256.81	0.068
SReff (% of pr.)	545.30 ± 279.00	278.90 ± 43.56	−47.62 ± 182.07	0.10
DLCO (ml/min/kPa)	2.28 ± 1.08	2.34 ± 1.09	0.19 ± 0.92	0.78
DLCO (% of pr.)	26.9% ± 11.8%	27.5% ± 11.7%	+0.67% ± 14.6%	0.82

FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity; RAW_tot: measured airway resistance; RV: residual volume; sRAW_tot: specific airway resistance; SR_eff: effective specific airway resistance; SR_tot: total specific airway resistance; TLC: total lung capacity.

At the 12-month follow-up, only few of the mentioned benefits lasted, with FEV₁, VC_in and 6-MWD having decreased below patient performances before ELVR in most cases. In comparison, VC_in had decreased by 0.05 ± 0.44 l, P = 0.56 and FEV₁ by 0.06 ± 0.16 l, P = 0.10. While RV/TLC turned out lower than before the procedure, the drop was insignificant (−1.21% ± 12.30%, P = 0.63). After 6–12 months, patients had walked 294.03 m on average during 6-MWD testing, 14.03 m less on average than before ELVR (P = 0.27). We checked for any correlation between emphysema distribution and long-term response after coil implantation in at least one of the following categories: (i) FEV₁, (ii) RV and (iii) 6-MWD. Interestingly, out of 12 patients qualifying as responders, 8 had homogenous and only 4 had heterogeneous emphysema. Table 3 provides a summary of relevant long-term outcomes.

Table 3:

Lung functional assessment of long-term effects of ELVR coils in patients with severe emphysema at least 6 months after the first coil treatment

	Before	After	Mean Δ	P-value
Lung function (n = 29)
FEV1 (l)	0.77 ± 0.31	0.72 ± 0.26	−0.06 ± 0.16	0.10
FEV1 (% of pr.)	28.32 ± 9.43	26.92 ± 9.00	1.40 ± 5.92	0.24
FVC (l)	1.83 ± 0.55	1.69 ± 0.55	−0.14 ± 0.35	0.058
FVC (% of pr.)	53.47 ± 14.09	50.12 ± 14.97	−3.35 ± 10.21	0.11
VCin	2.16 ± 0.76	2.11 ± 0.64	−0.05 ± 0.44	0.56
VCin (% of pr.)	62.47 ± 16.79	61.03 ± 17.27	−1.44 ± 10.66	0.51
RV (l)	5.68 ± 0.97	5.83 ± 1.29	0.15 ± 1.08	0.51
RV (% of pr.)	253.74 ± 53.26	257.52 ± 56.18	3.77 ± 50.11	0.71
RV/TLC (%)	72.28 ± 7.77	71.07 ± 14.85	−1.21 ± 12.30	0.63
SRtot (% of pr.)	708.86 ± 440.73	704.84 ± 413.92	−4.02 ± 271.87	0.94
SReff (% of pr.)	563.35 ± 296.74	556.88 ± 273.73	—6.47 ± 183.13	0.86
Exercise capacity (n = 29)
6-min WT (m)	308.06 ± 89.56	294.03 ± 104.04	−14.03 ± 73.52	0.27
Breaks	0.76 ± 1.58	0.76 ± 1.42	0.00 ± 1.04	1.00
O2-suppl. (lpm)	1.57 ± 1.52	1.82 ± 1.64	0.25 ± 1.14	0.21
HR before	87.18 ± 14.63	92.88 ± 18.84	5.71 ± 20.80	0.76
HR after	100.85 ± 19.14	99.56 ± 21.76	−1.29 ± 24.32	0.76
SO2 before	93.82 ± 1.98	94.32 ± 2.06	0.49 ± 2.00	0.16
SO2 after	88.77 ± 6.87	88.48 ± 7.07	−0.29 ± 4.53	0.71

FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity; HR: heart rate; RAW_tot: measured airway resistance; RV: residual volume; sRAW_tot: specific airway resistance; SR_eff: effective specific airway resistance; SR_tot: total specific airway resistance; TLC: total lung capacity; WT: walk test.

The median BODE index of patients immediately prior to ELVR was 5, predicting a 48-month survival rate of 57% [12]. Figure 1 shows Kaplan–Meier plots for our study cohort. Three patients received lung transplants during follow-up. Primary outcome was defined as ‘survival without transplant’. Kaplan–Meier plots reveal a 48-month survival of 63.8%. Comparison to Celli et al.’s [12] historic COPD cohort revealed no significant difference, implying that ELVR treatment did not increase survival above what would be projected by BODE indices at the time of ELVR.

Figure 1:

Patient survival without lung transplant following endoscopic lung volume reduction—long-term survival 48 months after endoscopic lung volume reduction treatment is plotted in a Kaplan–Meier curve together with a 95% confidence interval. Three patients received lung transplant during follow-up. Overall survival without transplant after 48 months was 63.8%. Patient BODE indices at the time of endoscopic lung volume reduction predicted an overall survival of 57% after 4 years [12] (marked with dotted lines), which fits well inside the 95% confidence interval of the actual survival curve.

In order to exclude that failure to improve a patient’s clinical condition by ELVR was due to misjudgement of the investigator as to which lung lobe should be targeted for coil placement, patient chest CT scans were submitted to 2 independent commercial providers of CT analysis software (A, PneumRX GmbH, Düsseldorf, Germany/B, PulmonX, Redwood City, CA, USA). Since both providers required CT slice thicknesses be no more than 1 mm, only 16 out of 29 CTs could be included in the analysis. When target lung lobes were determined by computed algorithms, the selected lobes differed from clinician’s choice in 18.75% and 30% of cases, respectively. We therefore checked for any correlation between not-responding to ELVR in any category and software-clinician-mismatch. Patients responded more frequently in 6-MWD (50% vs 30%) and RV (66.7% vs 38.5%) but less frequently in FEV₁ (33.3% vs 38.5%) when the investigator had treated a different lung lobe than suggested by software A. The opposite was true for Software B. Patients had benefitted less frequently in 6-MWD and FEV₁ (40% vs 33.3% and 57.1% vs 33.3%, respectively) when computed target lobes diverged from investigator’s choice. Response in RV in turn was observed more often in case of software-investigator-mismatch (33.3% vs 16.7%).

DISCUSSION

The main results of this study are: (i) the implantation of coils for ELVR does not result in a clinically relevant or sustained benefit for patients with severe COPD and (ii) there is no long-term survival benefit after 48 months.

The efficacy of ELVR treatment has been investigated in detail during the past 10 years, both in uncontrolled [13, 14] and controlled [11, 15, 16] clinical trials. While some investigators have come to favourable conclusions regarding the benefits of coil placement, many results have questioned its clinical value, especially since it appears to come with higher complication rates compared to optimal medical treatment [10, 15].

Given current literature, 29 patients can be considered as a relatively large cohort for a single-centre analysis, as a total of 60 patients were included in a European multicentre randomized controlled trial at the same time and the Swiss National Registry comprises 64 patients treated over a period of 3 years [15, 16]. Since all procedures were performed by the same interventionalist, variance in procedure quality is unlikely to affect patient’s outcomes. There was no statistically significant overall improvement in either lung function or exercise capacity 6 months after ELVR. Singling out distinct patients, some achieved greater improvements of FEV₁, RV and 6-MWD than others. Donohue [13] has previously defined ‘responders’ from ELVR as patients achieving an increase in FEV₁ by at least 100 ml. Similar propositions have been made for RV (at least −430 ml) [9] as well as 6-MWD [10] (at least +23 m) and are commonly employed as ELVR response criteria. In this study, 48.3% of patients showed short-term increases in FEV₁ of at least 100 ml or more thus potentially qualifying as short-term responders. Response in RV was less frequently observed (31.03%). Only 7 out of 29 patients benefited in both categories. Only 4 out of 25 patients had increases in 6-MWD of more than 26 m (4 patients lost to follow-up), but only 2 of them also qualified as responders in FEV₁ or RV, suggesting that response in lung function does not sufficiently correlate to changes in exercise capacity or symptom burden.

CT scans were submitted to 2 independent commercial providers of CT analysis software to exclude that failure to improve by ELVR was due to misjudgement of the investigator. When target lung lobes were determined by computed algorithms, the selected lobes differed from clinician’s choice in 18.75% and 30% of cases, respectively. Judging from both comparisons, determination of target lung lobes for ELVR coils by 2 commercially available software products was not superior to investigator’s choice. Mismatch occurred most often in patients with homogenous distribution of emphysema. Admittedly, one software was not designed to guide coil implantation and the number of properly analysed CT scans is low, so a definite conclusion if software guided coil deployment is superior to investigator guided is not possible from the data presented here. In all non-obvious cases, data from both structural analysis (X-ray, CT) and functional investigations (V/Q scans) should be combined when selecting target lung lobes for either coil or EBV implantation.

Results from this single-centre cohort study indicate that ELVR coils did not benefit most patients with severe emphysema. Since most published randomized controlled trials investigating ELVC come to more optimistic conclusions, we first compared the results to the patient baseline characteristics. The patient populations were very comparable regarding age, sex distribution, body mass index and FEV₁ [14–16], while average forced vital capacity and 6-MWD were slightly more severely impaired in our study population. Residual volume (RV) as well as RV/TLC on the other hand were quite congruent, indicating that our patient collective mostly represented that of larger RCTs investigating ELVR coils. In addition, the number of placed coils per sitting was also 10 on average per procedure. We therefore conclude that a possible beneficial effect was neither disguised by a more morbid cohort, nor by a difference in the procedure itself or the interventionalist’s experience.

In May 2019, Slebos et al. [17] proposed computed analysis of patient chest CT scans and RV >200% as predictors of response to coils. Interestingly, 60% of long-term responders in our study had baseline RV below 200% of expected. Additionally, subgroup comparison revealed that response rate was not higher in those cases when investigator’s CT analysis overlapped with software-based analysis. We conclude that response criteria as suggested by Slebos et al. did not translate to our study cohort, as they did not identify those patients who ended up benefitting from ELVR.

Comparing the rate of major complications in our study, 6.9% ranked well below what was reported from most above-mentioned clinical trials. It should be noted though that 40% of our patients had haemoptysis to varying degrees postintervention, in one case requiring intensive care. Survival without transplant after 48 months was well comparable to what was predicted by BODE indices, indicating that ELVR coils had no relevant effect on patient long-term prognosis.

Our study has several important limitations that need to be addressed. The study is a single-centre retrospective real-life assessment of ELVR using coils. While the baseline parameters of treated patients and primary results of the intervention were comparable to those of other studies, our patients seemed to deteriorate earlier than those of other cohorts. However, we did not compare the results of the intervention to a cohort receiving optimal non-interventional therapy only. We therefore cannot say whether patient lung function tests may have been worse at 12 months if no coils at all were inserted. Additionally, we did not perform an analysis of the patient quality of life. This would have been interesting additional information; however, the data had not been consequently collected in this real-world setting for most of the patients. It appears likely that improvement in quality of life can lag behind improvements in lung function after ELVR [18, 19]. Interventionalists should explain this to all patients deciding to undergo interventional lung volume reduction to help build realistic expectations.

Another limitation is the fact that some patients did not receive treatment of the contralateral side and 6 patients had previously received valves, as they had complete lobar fissure without collateral ventilation in a target lobe.

Most importantly, some patients received predominantly coils of 100 mm length, which might have led to less lung tissue compression than what might have been achieved through larger coils. The strategy to implant bigger coils, eventually creating more elastic recoil, was adopted during the study period. However, the impact of coil-size on patient outcome after ELVR is currently unclear.

CONCLUSION

In this retrospective analysis, ELVR coils led to small and short-lived benefits in lung function and/or exercise capacity in some patients with severe emphysema. Benefits could not be sustained longer than 6 months on average. Response in lung function to ELVR does not adequately correlate to benefits in exercise capacity or quality of life. Given a major complication rate of 6.9% (similar to surgical complication rates) in a highly morbid cohort, we deem the changes induced by ELVR with coils not worthwhile the risk for COPD patients with severe emphysema. Patients with severe emphysema should be discussed in an interdisciplinary board consisting of surgeons and interventional pneumologists to define the best strategy regarding lung volume reduction. Coil treatment might be an alternative for patients who do not qualify for either EBV or lunge volume reduction surgery and who are explicitly willing to take the risk of the procedure.

Data availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Conflict of interest: Robert Bals received funding from AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline, Grifols, Novartis, CSL Behring, German Federal Ministry of Education and Research (BMBF) Competence Network, Sander Stiftung, Dr. Rolf M. Schwiete Foundation, German Cancer help (Krebshilfe) and Mukosizidose e.V. All other authors declare no conflict of interest. 

Author contributions

Sebastian Mang: Data curation; Formal analysis; Writing—original draft. Niklas Huss: Data curation; Formal analysis; Writing—review & editing. Hans-Joachim Schäfers: Formal analysis; Supervision; Writing—review & editing. Holger Wehrfritz: Data curation; Writing—review & editing. Alexander Massmann: Methodology; Writing—review & editing. Christian Lensch: Formal analysis; Writing—review & editing; Patient Care. Frank Langer: Formal analysis; Writing—review & editing; Patient Care. Frederik Seiler: Formal analysis; Writing—review & editing; Patient Care. Robert Bals: Formal analysis; Supervision; Writing—review & editing. Philipp M. Lepper: Conceptualization; Data curation; Formal analysis; Supervision; Writing—original draft; Writing—review & editing; Performed the intervention.

Reviewer information

Interactive CardioVascular and Thoracic Surgery thanks Paola Ciriaco and the other anonymous reviewer(s) for their contribution to the peer review process of this article.

Abbreviations

6-MWD

6 minute walking distance

COPD

Chronic obstructive pulmonary disease

CT

Computer tomography

EBV

Endobronchial valves

ELVR

Endoscopic lung volume reduction

FEV₁

Forced expiratory volume in 1 s

LVRS

Lung volume reduction surgery

RV

Residual volume

TLC

Total lung capacity

V/Q

Ventilation/perfusion

VC

Vital capacity

 

An early version of the manuscript has been uploaded to the Preprint Server Research Square and can be found under https://doi.org/10.21203/rs.3.rs-60941/v1.