Increased residual volume is associated with a larger pulmonary artery in patients with COPD, according to a study published in Plos One. The results suggest that gas trapping may contribute to pulmonary hypertension among patients with COPD, Clinical Advisor reports.

The participants underwent body plethysmography, and a cardiac MRI was performed to measure the cross-sectional area of the main pulmonary artery. The investigators assessed percent emphysema, which was defined as “the percentage of lung voxels less than -950 Hounsfield units as assessed via X-ray computed tomography.”

The researchers found that the mean residual volume was 1.98 ± 0.71 L and the mean pulmonary artery cross-sectional area was 7.23 ± 1.72 cm2. They noted that one standard deviation increase in residual volume was associated with an increase in main pulmonary artery cross-sectional area of 0.55 cm2. However, there was no evidence of an association with percent emphysema or total lung capacity.