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Abstract
Rationale Endoscopic lung volume reduction improves lung function, quality of life and exercise capacity in severe emphysema patients. However, its effect on the diaphragm function is not well understood. We hypothesised that endoscopic lung volume reduction increases its strength by modifying its shape.
Objectives To investigate changes in both diaphragm shape and strength induced by the insertion of endobronchial valves.
Methods In 19 patients, both the diaphragm shape and strength were investigated respectively by 3D Slicer software applied on CT scans acquired at functional residual capacity and by transdiaphragmatic pressure measurements by bilateral magnetic stimulation of the phrenic nerves before and 3 months after unilateral valves insertion.
Measurements and main results After lung volume reduction (median (IQR), 434 mL (−597 to −156], p<0.0001), diaphragm strength increased (transdiaphragmatic pressure: 3 cmH2O (2.3 to 4.2), p<0.0001). On the treated side, this increase was associated with an increase in the coronal (16 mm (13 to 24), p<0.0001) and sagittal (26 mm (21 to 30), p<0.0001) lengths as well as in the area of the zone of apposition (62 cm2 (3 to 100), p<0.0001) with a decrease in the coronal (8 mm (−12 to −4), p<0.0001) and sagittal (9 mm (−18 to −2), p=0.0029) radii of curvature.
Conclusions Endoscopic lung volume reduction modifies the diaphragm shape by increasing its length and its zone of apposition and by decreasing its radius of curvature on the treated side, resulting in an increase in its strength.
Trial registration number NCT05799352.
- Emphysema
- Respiratory Muscles
Data availability statement
Data are available upon reasonable request. All data relevant to the study are included in the article or uploaded as supplementary information.
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Data availability statement
Data are available upon reasonable request. All data relevant to the study are included in the article or uploaded as supplementary information.
Footnotes
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Contributors OT, BB, SVL and DL performed the endoscopic procedures and patients’ follow-up. OT and PAG performed the radiological examination of this study. AVM performed the mathematical model of the thorax segmentation and the statistical analyses. OT, SVL and DL performed the transdiaphragmatic pressure evaluation. All authors declare substantial contributions to the conception, design, acquisition, analysis and interpretation of the data of this research. They have all participated to writing and revising important intellectual content and approved the final version of this manuscript to be submitted for consideration for publication. They all agree to be accountable for every aspect of their work by ensuring that questions related to the accuracy or integrity of any part of this research were appropriately investigated and resolved. OT is the guarantor of this study and accepts full responsibility for the finished work and/or the conduct of the study, had access to the data and controlled the decision to publish.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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