Pulmonary Vascular Volume by Quantitative CT in Dyspneic Smokers with Minor Emphysema. (31st December 2023)

• Record Type: Journal Article
• Authors: Elbehairy, Amany F.; Vincent, Sandra G.; Phillips, Devin B.; James, Matthew D.; Veugen, Jenna; Parraga, Grace; O'Donnell, Denis E.; Neder, J. Alberto
• Is Part Of: COPD. Volume 20:Number 1(2023)
• Page Start: 135
• Page End: 143
• Publication Date: 2023-12-31
• Subjects: Smoking -- pulmonary vascular volume -- DLCO -- dyspnea -- CT -- emphysema; Lungs -- Diseases, Obstructive -- Periodicals; 616.24
• DOI: 10.1080/15412555.2023.2169121
• Languages: English
• ISSNs: 1541-2555

Abstract

Abstract: Reduced lung diffusing capacity for carbon monoxide (DLCO ) at rest and increased ventilation (⩒ E )-carbon dioxide output (⩒ CO2 ) during exercise are frequent findings in dyspneic smokers with largely preserved FEV1 . It remains unclear whether low DLCO and high ⩒ E -⩒ CO2 are mere reflections of alveolar destruction (i.e. emphysema) or impaired pulmonary perfusion in non-emphysematous tissue contributes to these functional abnormalities. Sixty-four smokers (41 males, FEV1 = 84 ± 13%predicted) underwent pulmonary function tests, an incremental exercise test, and quantitative chest computed tomography. Total pulmonary vascular volume (TPVV) was calculated for the entire segmented vascular tree (VIDA Vision™). Using the median % low attenuation area (-950 HU), participants were dichotomized into "Trace" or "Mild" emphysema (E), each group classified into preserved versus reduced DLCO . Within each emphysema subgroup, participants with abnormally low DLCO showed lower TPVV, higher ⩒ E -⩒ CO2, and exertional dyspnea than those with preserved DLCO ( p < 0.05). TPVV ( r = 0.34; p = 0.01), but not emphysema ( r = −0.05; p = 0.67), correlated with lower DLCO after adjusting for age and height. Despite lower emphysema burden, Trace-E participants with reduced DLCO had lower TPVV, higher dyspnea, and lower peak work rate than the Mild-E with preserved DLCO ( p < 0.05). Interestingly, TPVV (but not emphysema) correlated inversely with both dyspnea-work rate ( r = −0.36, p = 0.004) and dyspnea-⩒ E slopes ( r = −0.40, p = 0.001). Reduced pulmonary vascular volume adjusted by emphysema extent is associated with low DLCO and heightened exertional ventilation in dyspneic smokers with minor emphysema. Impaired perfusion of non-emphysematous regions of the lungs has greater functional and clinical consequences than hitherto assumed in these subjects.