COPD phenotypes by high resolution computed tomography (HRCT) and ventilatory response to exercise:

Aim: To ascertain whether a relationship between HRCT phenotyping and the ventilatory response during an incremental cardiopulmonary exercise testing (CPET) occurs in COPD patients. Methods: The extent of emphysema (EE %), airway disease (quantified as wall area percent, WA %) on HRCT as well as the ratio of inspiratory capacity/total lung capacity (IC/TLC) at rest and peak of exercise and the slope and intercept of the minute ventilation/carbon dioxide output (VE/VCO2) linear relationshipduring a CPET were measured in 51 COPD patients. Spirometry, plethysmography and lung diffusion capacity were also measured. Results: Patients were classified in 4 HRCT phenotypes: HighEE&LowWA (HL), HighEE&HighWA (HH); LowEE&LowWA (LL); LowEE&HighWA (LH). Demographic, lung function and exercise data are listed in the table. Conclusions: In COPD patients, the HRCT phenotype with high EE and WA was associated with poor resting lung function and ventilatory response to exercise, as assessed by changes in the end-expiratory lung volume but not as VE/VCO2 slope and intercept.