COPD phenotypes by computed tomography and ventilatory response to exercise

Introduction: CT phenotypic patterns of chronic obstructive pulmonary (COPD) defining emphysema-dominant versus airway-dominant groups identify different clinical features of disease. The impact of these variables on the physiological response to exercise has been a great deal of research. Objective: To evaluate the relationship between CT phenotyping of COPD patients and the ventilatory response during cardiopulmonary exercise testing (CPET). Methods: Patients with COPD were classified into 4 phenotypes based on CT using two cut-offs: percentage of low attenuation area (%LAA) less than a threshold of -950 Hounsfield units of 15% and median value of the percentage of bronchial mean wall area (MWA%). Results: Eighty COPD patients (78.8% males, median age 65±1.3 years) were enrolled in the study. Based on CT phenotype, 25 (31,3%) patients were classified as normal, 27 (33,8%) air dominant, 17 (21,3%) emphysema dominant and 11 (13,8%) mixed type. The emphysema dominant phenotype showed the lowest peak aerobic capacity (VO2), the highest ventilatory equivalent for oxygen (VE/VO2) and for carbon dioxide (VE/VCO2) among the four groups (p Conclusion: CPET parameters such as aerobic capacity and ventilatory demands (VE/VO2, VE/VCO2) were associated with emphysematous change. These results suggested that phenotyping of CT may help predicting ventilatory response to exercise in COPD patients.