Pulmonary hyperinflation due to gas trapping and pulmonary artery size: The MESA COPD Study

• Published in: PloS one 2017-05, Vol.12 (5), p.e0176812-e0176812
• Main Authors: Poor, Hooman D, Kawut, Steven M, Liu, Chia-Ying, Smith, Benjamin M, Hoffman, Eric A, Lima, João A, Ambale-Venkatesh, Bharath, Michos, Erin D, Prince, Martin R, Barr, R Graham
• Format: Article
• Language: English
• Subjects: Abnormalities; Acidosis; Adults; Age; Aged; Air flow; Alveoli; Aorta; Apnea; Arteriosclerosis; Asthma; Atherosclerosis; Biology and Life Sciences; Blood; Blood circulation; Blood flow; Blood pressure; Blood volume; Bronchitis; Cancer; Cardiovascular disease; Cardiovascular diseases; Causes of; Chronic obstructive lung disease; Chronic obstructive pulmonary disease; Cohort Studies; Computation; Computed tomography; Coronary artery disease; Critical care; Cross-Sectional Studies; Destruction; Emphysema; Epidemiology; Female; Forced Expiratory Volume; Gadolinium; Gas exchange; Health aspects; Health care; Heart; Heart - diagnostic imaging; Heart diseases; Hemodynamics; Humans; Hypercapnia; Hypertension; Hypertension, Pulmonary - diagnostic imaging; Hypertension, Pulmonary - physiopathology; Hyperventilation; Hypoxia; Lung - diagnostic imaging; Lung - physiopathology; Lung diseases; Lungs; Magnetic resonance; Magnetic Resonance Imaging; Male; Maneuvers; Medical imaging; Medicine; Medicine and Health Sciences; Middle Aged; Morbidity; Mortality; NMR; Nuclear magnetic resonance; Organ Size; Oxygen; pH effects; Physical Sciences; Physiological aspects; Plethysmography, Whole Body; Pulmonary arteries; Pulmonary artery; Pulmonary Artery - diagnostic imaging; Pulmonary Disease, Chronic Obstructive - diagnostic imaging; Pulmonary Disease, Chronic Obstructive - physiopathology; Pulmonary Emphysema - diagnostic imaging; Pulmonary Emphysema - physiopathology; Pulmonary hypertension; Quantitation; Radiology; Research and Analysis Methods; Residual Volume; Resonance; Respiration; Respiratory function; Sleep; Smoking; Tomography; Tomography, X-Ray Computed; Transplantation; Transplants & implants; Trapping; Vasoconstriction; Ventricle
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0176812

Pulmonary hypertension is associated with increased morbidity and mortality in chronic obstructive pulmonary disease (COPD). Since pulmonary artery (PA) size increases in pulmonary hypertension, we measured PA cross-sectional area using magnetic resonance imaging (MRI) to test the hypothesis that pulmonary hyperinflation due to gas trapping is associated with PA cross-sectional area in COPD. The MESA COPD Study recruited participants with COPD and controls from two population-based cohort studies ages 50-79 years with 10 or more pack-years and free of clinical cardiovascular disease. Body plethysmography was performed according to standard criteria. Cardiac MRI was performed at functional residual capacity to measure the cross-sectional area of the main PA. Percent emphysema was defined as the percentage of lung voxels less than -950 Hounsfield units as assessed via x-ray computed tomography. Analyses were adjusted for age, gender, height, weight, race-ethnicity, the forced expiratory volume in one second, smoking status, pack-years, lung function, oxygen saturation, blood pressure, left ventricular ejection fraction and percent emphysema. Among 106 participants, mean residual volume was 1.98±0.71 L and the mean PA cross-sectional area was 7.23±1.72 cm2. A one standard deviation increase in residual volume was independently associated with an increase in main PA cross-sectional area of 0.55 cm2 (95% CI 0.18 to 0.92; p = 0.003). In contrast, there was no evidence for an association with percent emphysema or total lung capacity. Increased residual volume was associated with a larger PA in COPD, suggesting that gas trapping may contribute to pulmonary hypertension in COPD.