Quantitative Chest Computed Tomography in Chronic Obstructive Pulmonary Disease: Assessing the Role of Emphysema Severity and its Correlation with Clinical Characteristics, Lung Function, and Plasma Levels of VEGF and IL-1β

Objective: This study aimed to evaluate the characteristics of emphysema in patients with Chronic Obstructive Pulmonary Disease (COPD) using quantitative computed tomography (QCT) and to investigate the relationship between the extent of emphysema, clinical phenotypes, lung function, and plasma concentrations of Vascular Endothelial Growth Factor (VEGF) and Interleukin-1β (IL-1β) in COPD patients. Methods: A prospective cross-sectional study was conducted on 30 male patients with stable COPD at Military Hospital 175. The emphysema index (EI) was quantified using QCT of the chest and categorized into levels from 0 to 4. Data on acute exacerbation frequency, COPD Assessment Test (CAT) scores, modified Medical Research Council (mMRC) dyspnea scale, pulmonary function indices (FEV1%, FEV1/FVC%), arterial blood gas measurements, and plasma concentrations of VEGF and IL-1β were collected and analyzed to determine their relationship with EI. Results: The study found an average EI of 12.8 ± 11.64%, with 96.7% of patients exhibiting a bronchitis-dominant phenotype (EI < 35%). Among the patients, 46.7% had level 2 emphysema, 16.6% had level 1, and 36.7% had level 0. The severity of airflow obstruction, as classified by the Global Initiative for Chronic Obstructive Lung Disease (GOLD), along with blood PaCO ₂ levels, mMRC scores, and the number of exacerbations per year, increased with the degree of emphysema. Conversely, FEV ₁ % and the FEV ₁ /FVC ratio significantly decreased with increasing emphysema severity. A significant inverse relationship was observed between EI and lung function (p < 0.01). Additionally, plasma VEGF concentration was inversely correlated with the EI (r = -0.5, p = 0.02), suggesting that reduced VEGF may play a critical role in pulmonary vascular destruction and remodeling, leading to more severe emphysema. Conclusion: The emphysema index (EI) determined by QCT is a valuable tool for identifying COPD phenotypes and assessing disease severity. It can also provide insights into the prognosis regarding the risk of exacerbations, clinical symptom burden, and lung function decline. The significant inverse correlation between plasma VEGF concentration and EI indicates that decreased VEGF levels may be a crucial factor in the pathogenesis of emphysema, suggesting a potential target for research on "treatable" factors in COPD management. Trial Registration: The study was approved by an independent ethics committee (Ethics Committee of Military Hospital 175, No. 003/QĐ-IRB-VN01.055) and conducted in accordance with the Declaration of Helsinki and Guidelines for Good Clinical Practice.