Computed Tomography-based Airway Surface Area-to-Volume Ratio for Phenotyping Airway Remodeling in Chronic Obstructive Pulmonary Disease

• Published in: American journal of respiratory and critical care medicine 2021-01, Vol.203 (2), p.185-191
• Main Authors: Bodduluri, Sandeep, Kizhakke Puliyakote, Abhilash, Nakhmani, Arie, Charbonnier, Jean-Paul, Reinhardt, Joseph M, Bhatt, Surya P
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Airway management; Airway Remodeling; Chronic obstructive pulmonary disease; Cone-Beam Computed Tomography; Female; Follow-Up Studies; Genotype & phenotype; Humans; Kaplan-Meier Estimate; Male; Medical research; Middle Aged; Organ Size; Original; Phenotype; Proportional Hazards Models; Pulmonary Disease, Chronic Obstructive - diagnostic imaging; Pulmonary Disease, Chronic Obstructive - pathology; Pulmonary Disease, Chronic Obstructive - physiopathology; Tomography
• ISSN: 1073-449X; 1535-4970
• DOI: 10.1164/rccm.202004-0951OC

Airway remodeling in chronic obstructive pulmonary disease (COPD) is due to luminal narrowing and/or loss of airways. Existing computed tomographic metrics of airway disease reflect only components of these processes. With progressive airway narrowing, the ratio of the airway luminal surface area to volume (SA/V) should increase, and with predominant airway loss, SA/V should decrease. To phenotype airway remodeling in COPD. We analyzed the airway trees of 4,325 subjects with COPD Global Initiative for Chronic Obstructive Lung Disease stages 0 to 4 and 73 nonsmokers enrolled in the multicenter COPDGene (Genetic Epidemiology of COPD) cohort. Surface area and volume measurements were estimated for the subtracheal airway tree to derive SA/V. We performed multivariable regression analyses to test associations between SA/V and lung function, 6-minute-walk distance, St. George's Respiratory Questionnaire, change in FEV , and mortality, adjusting for demographics, total airway count, airway wall thickness, and emphysema. On the basis of the change in SA/V over 5 years, we categorized subjects into predominant airway narrowing [positive ∆(SA/V) more than 0] and predominant airway loss [negative ∆(SA/V) less than 0] and compared survival between the two groups. Airway SA/V was independently associated with FEV /FVC (β = 0.12; 95% confidence interval [CI], 0.09-0.14;