Pulmonary Arterial Pruning Associated With Faster Progression of Percent Emphysema

Greater pulmonary vascular pruning, or a lower ratio of small artery volume (<5 mmg² in cross-sectional area [CSA]) to total lung vessel volume, is associated with more rapid progression of percent emphysema as well as faster decline in forced expiratory volume in 1 second (FEV₁)/forced vital capacity (FVC) over 5 years in ever-smokers, according to findings from the COPDGene Study published in CHEST.

Researchers enrolled a total of 10,263 ever-smokers with and without COPD in the COPDGene Study between 2008 and 2011. Only 4227 participants who were included in the emphysema analyses were included in this analysis of the COPDGene study (mean age, 60±9 years). Investigators measured the percent of emphysema-like lung at baseline and at 5-year follow up on noncontrast computed tomography (CT). Additionally, the researchers used an automated CT-based tool to evaluate and classify intrapulmonary arteries and veins.

The median percent emphysema in the population was 2.1 (interquartile range, 0.6-6.3) and progressed 0.24 percentage points per year (95% CI, 0.22-0.26) over a 5.6-year period. Additionally, the mean FEV₁/FVC was 68.5%±14.2% and decreased 0.26% per year (95% CI, -0.30% to -0.23%).

In this study, pulmonary arterial pruning was defined as a lower ratio of vessel volume less than 5 mmg² in CSA to total lung vessel volume. Greater pulmonary arterial pruning was significantly associated with faster progression of percent emphysema (0.11 percentage points/y per standard deviation [SD] increase in arterial pruning; 95% CI, 0.09%-0.13%; P <.001). In addition, arterial pruning was associated with a more rapid decline in FEV₁/FVC (-0.04%/y per SD arterial pruning; 95% CI, -0.08% to -0.001%; P =.042).

Limitations of this study included the lack of microvasculature in noncontrast CT measures of pulmonary vasculature as well as the potential selection bias caused by the loss to follow- up.

The researchers noted that their study “adds to prior data suggesting that the pulmonary vasculature may be important in emphysema and COPD and that “further study of small pulmonary arteries and vascular pruning may yield insights into disease progression.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Pistenmaa CL, Nardelli P, Ash SY, et al; for the COPDGene Investigators. Pulmonary arterial pruning and longitudinal change in percent emphysema and lung function: the COPDGene study CHEST. Published online February 16, 2021. doi:10.1016/j.chest.2021.01.084