Predictors of pneumothorax following endoscopic valve therapy in patients with severe emphysema

Abstract

Background

Endoscopic valve implantation is an effective treatment for patients with advanced emphysema. Despite the minimally invasive procedure, valve placement is associated with risks, the most common of which is pneumothorax. This study was designed to identify predictors of pneumothorax following endoscopic valve implantation.

Methods

Preinterventional clinical measures (vital capacity, forced expiratory volume in 1 second, residual volume, total lung capacity, 6-minute walk test), qualitative computed tomography (CT) parameters (fissure integrity, blebs/bulla, subpleural nodules, pleural adhesions, partial atelectasis, fibrotic bands, emphysema type) and quantitative CT parameters (volume and low attenuation volume of the target lobe and the ipsilateral untreated lobe, target air trapping, ipsilateral lobe volume/hemithorax volume, collapsibility of the target lobe and the ipsilateral untreated lobe) were retrospectively evaluated in patients who underwent endoscopic valve placement (n=129). Regression analysis was performed to compare those who developed pneumothorax following valve therapy (n=46) with those who developed target lobe volume reduction without pneumothorax (n=83).

Finding

Low attenuation volume% of ipsilateral untreated lobe (odds ratio [OR] =1.08, P=0.001), ipsilateral untreated lobe volume/hemithorax volume (OR =0.93, P=0.017), emphysema type (OR =0.26, P=0.018), pleural adhesions (OR =0.33, P=0.012) and residual volume (OR =1.58, P=0.012) were found to be significant predictors of pneumothorax. Fissure integrity (OR =1.16, P=0.075) and 6-minute walk test (OR =1.05, P=0.077) were also indicative of pneumothorax. The model including the aforementioned parameters predicted whether a patient would experience a pneumothorax 84% of the time (area under the curve =0.84).

Interpretation

Clinical and CT parameters provide a promising tool to effectively identify patients at high risk of pneumothorax following endoscopic valve therapy.

Keywords:

• endoscopic lung volume reduction
• COPD
• emphysema
• pneumothorax
• valve therapy

Acknowledgments

The authors thank Dr Filippos Filippidis, Lecturer in Public Health at Imperial College, London, UK, for providing statistical advice.

Author contributions

All authors participated in trial coordination and study design and contributed toward data analysis, drafting and revising the paper, and agree to be accountable for all aspects of the work. The final submitted version was approved by all the authors.

Disclosure

DG: Lecture and travel fees from Pulmonx, Novartis, Astra Zeneca, Munidpharma, and Grifols. HL and VG: No conflicts of interest. RE: Lecture and travel fees from Pulmonx and Olympus. FJFH: Consultant and lecture fee from Astra, Allmirall, Berlin Chemie, Boehringer, Roche, GSK, Pulmonx, PneumRx, Boston Scientific, Medupdate, Grifols, CSL Behring, Omniamed, Lilly, Novartis, Teva, Uptake, and Vital Air. CPH: Stock ownership in medical industry (Stada, GSK); Patents Method and Device for Representing the Microstructure of the Lungs. IPC8 Class: AA61B5055FI, PAN: 20080208038, Inventors: W Schreiber, U Wolf, AW Scholz, CP Heussel; Consultation or other fees (Schering-Plough 2009, 2010, Pfizer 2008–2014, Basilea 2008, 2009, 2010, Boehringer Ingelheim 2010–2014, Novartis 2010, 2012, Roche 2010, Astellas 2011, 2012, Gilead 2011–2014, MSD 2011–2013, Lilly 2011, Intermune 2013–2014, Fresenius 2013, 2014); Expert testimony (no); Research funding (Siemens 2012–2014, Pfizer 2012–2014, MeVis 2012, 2013, Boehringer Ingelheim 2015); Lecture fees (Gilead 2008–2014, Essex 2008, 2009, 2010, Schering-Plough 2008, 2009, 2010, AstraZeneca 2008–2012, Lilly 2008, 2009, 2012, Roche 2008, 2009, MSD 2009–2014, Pfizer 2010–2014, Bracco 2010, 2011, MEDA Pharma 2011, Intermune 2011–2014, Chiesi 2012, Siemens 2012, Covidien 2012, Pierre Fabre 2012, Boehringer Ingelheim 2012, 2013, 2014, Grifols 2012, Novartis 2013, 2014); Tobacco industry (no relationship). ME: Consultation fee Roche, 2015 and Novartis, 2015. The authors report no other conflicts of interest in this work.