Computed Tomographic Measures of Pulmonary Vascular Morphology in Smokers and Their Clinical Implications.
Estepar, Raul San Jose 1,2,3; Kinney, Gregory L. 6; Black-Shinn, Jennifer L. 6; Bowler, Russell P. 7; Kindlmann, Gordon L. 9; Ross, James C. 3,7; Kikinis, Ron 1,2; Han, MeiLan K. 10; Come, Carolyn E. 4; Diaz, Alejandro A. 4; Cho, Michael H. 7,9; Hersh, Craig P. 7,9; Schroeder, Joyce D. 8; Reilly, John J. 11; Lynch, David A. 8; Crapo, James D. 12; Wells, Michael J. 13; Dransfield, Mark T. 13; Hokanson, John E. 6; Washko, George R. 7; for the COPDGene Study
[Miscellaneous Article]
American Journal of Respiratory & Critical Care Medicine.
188(2):231-239, July 15, 2013.
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Rationale: Angiographic investigation suggests that pulmonary vascular remodeling in smokers is characterized by distal pruning of the blood vessels.
Objectives: Using volumetric computed tomography scans of the chest we sought to quantitatively evaluate this process and assess its clinical associations.
Methods: Pulmonary vessels were automatically identified, segmented, and measured. Total blood vessel volume (TBV) and the aggregate vessel volume for vessels less than 5 mm2 (BV5) were calculated for all lobes. The lobe-specific BV5 measures were normalized to the TBV of that lobe and the nonvascular tissue volume (BV5/TissueV) to calculate lobe-specific BV5/TBV and BV5/TissueV ratios. Densitometric measures of emphysema were obtained using a Hounsfield unit threshold of -950 (%LAA-950). Measures of chronic obstructive pulmonary disease severity included single breath measures of diffusing capacity of carbon monoxide, oxygen saturation, the 6-minute-walk distance, St George's Respiratory Questionnaire total score (SGRQ), and the body mass index, airflow obstruction, dyspnea, and exercise capacity (BODE) index.
Measurements and Main Results: The %LAA-950 was inversely related to all calculated vascular ratios. In multivariate models including age, sex, and %LAA-950, lobe-specific measurements of BV5/TBV were directly related to resting oxygen saturation and inversely associated with both the SGRQ and BODE scores. In similar multivariate adjustment lobe-specific BV5/TissueV ratios were inversely related to resting oxygen saturation, diffusing capacity of carbon monoxide, 6-minute-walk distance, and directly related to the SGRQ and BODE.
Conclusions: Smoking-related chronic obstructive pulmonary disease is characterized by distal pruning of the small blood vessels (<5 mm2) and loss of tissue in excess of the vasculature. The magnitude of these changes predicts the clinical severity of disease.
(C) 2013 American Thoracic Society