COPD beyond proximal bronchial obstruction: phenotyping and related tools at the bedside. (8th July 2019)

• Record Type: Journal Article
• Authors: Capron, Thibaut; Bourdin, Arnaud; Perez, Thierry; Chanez, Pascal
• Is Part Of: European respiratory review. Volume 28:Number 152(2019)
• Publication Date: 2019-07-08
• Subjects: Respiratory organs -- Diseases -- Periodicals; Respiratory Tract Diseases; Respiratory organs -- Diseases; Respiratory organs -- Diseases -- Treatment; Electronic journals; Periodical; Periodicals; Periodicals; 616.2
• DOI: 10.1183/16000617.0010-2019
• Languages: English
• ISSNs: 0905-9180

Abstract

Chronic obstructive pulmonary disease (COPD) is characterised by nonreversible proximal bronchial obstruction leading to major respiratory disability. However, patient phenotypes better capture the heterogeneously reported complaints and symptoms of COPD. Recent studies provided evidence that classical bronchial obstruction does not properly reflect respiratory disability, and symptoms now form the new paradigm for assessment of disease severity and guidance of therapeutic strategies. The aim of this review was to explore pathways addressing COPD pathogenesis beyond proximal bronchial obstruction and to highlight innovative and promising tools for phenotyping and bedside assessment. Distal small airways imaging allows quantitative characterisation of emphysema and functional air trapping. Micro-computed tomography and parametric response mapping suggest small airways disease precedes emphysema destruction. Small airways can be assessed functionally using nitrogen washout, probing ventilation at conductive or acinar levels, and forced oscillation technique. These tests may better correlate with respiratory symptoms and may well capture bronchodilation effects beyond proximal obstruction. Knowledge of inflammation-based processes has not provided well-identified targets so far, and eosinophils probably play a minor role. Adaptative immunity or specific small airways secretory protein may provide new therapeutic targets. Pulmonary vasculature is involved in emphysema through capillary loss, microvascular lesions or hypoxia-induced remodelling, thereby impacting respiratory disability. COPD bronchial obstruction poorly reflects respiratory disability; this review addresses pathways for pathogenesis beyond proximal obstruction through small airways imaging and function, inflammation processes and pulmonary vascular involvement. bit.ly/30JlKVi