title: Effect of endobronchial valve therapy on pulmonary perfusion and ventilation distribution.
abstract: BACKGROUND
  Endoscopic lung volume reduction (ELVR) is an emerging therapy for emphysematous COPD. However, any resulting changes in lung perfusion and ventilation remain undetermined. Here, we report ELVR-mediated adaptations in lung perfusion and ventilation, as investigated by means of pulmonary scintigraphy.
  
  
  METHODS
  In this observational study, we enrolled 26 patients (64.9 ± 9.4 yrs, 57.7% male) with COPD heterogeneous emphysema undergoing ELVR with endobronchial valves (Zephyr, Pulmonx, Inc.). Mean baseline FEV1 and RV were 32.9% and 253.8% predicted, respectively. Lung scintigraphy was conducted prior to ELVR and eight weeks thereafter. Analyses of perfusion and ventilation shifts were performed and complemented by correlation analyses between paired zones.
  
  
  RESULTS
  After ELVR, target zone perfusion showed a mean relative reduction of 43.32% (p<0.001), which was associated with a significant decrease in target zone ventilation (p<0.001). Perfusion of the contralateral untreated zone and of the contralateral total lung exhibited significant increases post-ELVR (p = 0.002 and p = 0.005, respectively); both correlated significantly with the corresponding target zone perfusion adaptations. Likewise, changes in target zone ventilation correlated significantly with ventilatory changes in the contralateral untreated zone and the total contralateral lung (Pearson's r: -0.42, p = 0.04 and Pearson's r: -0.42, p = 0.03, respectively). These effects were observed in case of clinical responsiveness to ELVR, as assessed by changes in the six-minute walk test distance.
  
  
  CONCLUSIONS
  ELVR induces a relevant decrease in perfusion and ventilation of the treated zone with compensatory perfusional and ventilatory redistribution to the contralateral lung, primarily to the non-concordant, contralateral zone.
authors.affiliation: Department of Internal Medicine II, Cardiology, Pneumology and Angiology, University Hospital Bonn, Bonn, Germany.
authors.forename: Carmen
authors.initials: C
authors.lastname: Pizarro
authors.affiliation: Department of Nuclear Medicine, University Hospital Bonn, Bonn, Germany.
authors.forename: Hojjat
authors.initials: H
authors.lastname: Ahmadzadehfar
authors.affiliation: Department of Nuclear Medicine, University Hospital Bonn, Bonn, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Essler
authors.affiliation: Department of Internal Medicine II, Cardiology, Pneumology and Angiology, University Hospital Bonn, Bonn, Germany.
authors.forename: Izabela
authors.initials: I
authors.lastname: Tuleta
authors.affiliation: Institute for Medical Biometry, Informatics and Epidemiology, University Hospital Bonn, Bonn, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Fimmers
authors.affiliation: Department of Internal Medicine II, Cardiology, Pneumology and Angiology, University Hospital Bonn, Bonn, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Nickenig
authors.affiliation: Department of Internal Medicine II, Cardiology, Pneumology and Angiology, University Hospital Bonn, Bonn, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Skowasch
mesh_terms: D000368:Aged; D001999:Bronchoscopy / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011013:Pneumonectomy / Q000009:adverse effects* / Q000379:methods; D029424:Pulmonary Disease, Chronic Obstructive / Q000628:therapy*; D011877:Radionuclide Imaging; D014692:Ventilation-Perfusion Ratio
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