Figures
- FIGURE 1
Illustration of intraparenchymal pulmonary vascular pruning in bronchiectasis. Axial computed tomography images of the right lower lobe (RLL) from subjects a) without and b) with bronchiectasis. c and d) Three-dimensional reconstructions of the intraparenchymal pulmonary vascular tree of the right lung from the same subjects. Note the lack of pulmonary vessels in the RLL from the subject with bronchiectasis (d). e) Plot of RLL blood vessel volume to the vessel size for both subjects. Note a lower peak in blood vessel volume of small, distal pulmonary vessels in the RLL of bronchiectatic lung compared with nonbronchiectatic lung.
- FIGURE 2
a) Forced expiratory volume in 1 s (FEV1) and b) 6-min walk test (6MWT) distance by bronchiectasis in any lobe/vascular pruning in the lower lobes groups (n=485). Group 0: bronchiectasis−/vascular pruning− (n=187); group 1: bronchiectasis+/vascular pruning− (n=82); group 2: bronchiectasis−/vascular pruning+ (n=143); group 3: bronchiectasis+/vascular pruning+ (n=73). Note that group 3 had lower FEV1 and 6MWT distance than group 1. p-values are from univariate models. See the main text for the results of the adjusted models. One subject was excluded from these analyses because of a missing right lower lobe ratio of blood vessel volume in vessels <5 mm2 in cross-section to total blood vessel volume, leaving a sample size of 485. The 6MWT distance measurement was missing in two additional subjects.
Tables
- TABLE 1
Demographic and clinical characteristics of the subjects by bronchiectasis status
Subjects without bronchiectasis Subjects with bronchiectasis p-value Subjects 331 155 Age years 60±9 64±9 <0.0001 Females 57% 68% 0.02 Non-Hispanic white race 78% 78% 0.98 Height cm 168±9 166±8 0.009 Body mass index kg·m−2 29±6 29±6 0.86 Current smoking status 41% 37% 0.33 Smoking history pack-years 45±25 45±23 0.93 Chronic heart failure 1.8% 0.7% 0.44 Coronary artery disease 10% 15% 0.12 FEV1 L 2.2±0.8 2.0±0.8 0.006 FEV1 % predicted 77±24 77±26 0.73 FVC L 3.3±0.9 3.0±0.9 0.002 FVC % predicted 88±17 88±19 0.84 TLCCT L 5.5±1.4 5.3±1.2 0.29 TLCCT % predicted 97±17 99±14 0.32 6-min walk test distance m 428±119 403±117 0.03 Resting SaO2 % 96±3 96±3 0.32 Spirometric COPD 47% 50% 0.52 Whole-lung TBV mL 277±61 275±59 0.68 Whole-lung BV5 mL 167±41 164±39 0.46 Whole-lung BV5/TBV % 60±6 60±7 0.45 Whole-lung %LAA−950 % 6.9±9.8 7.3±9.0 0.72 Upper-lobe %LAA−950 % 7.8±10.8 7.9±9.3 0.90 Lower-lobe %LAA−950 % 5.5±8.0 6.3±8.8 0.31 Data are presented as mean±sd, unless otherwise stated. Missing data: total lung capacity determined by computed tomography (TLCCT), n=4; TLCCT % predicted, n=4; 6-min walk test, n=2; whole-lung percentage of low-attenuation areas below −950 Hounsfield units (%LAA−950), n=4; %LAA−950 of the upper and lower lobes, n=4. FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; SaO2: arterial oxygen saturation; COPD: chronic obstructive pulmonary disease; TBV: total blood vessel volume; BV5: blood vessel volume in vessels <5 mm2 in cross-section.
- TABLE 2
Description of the computed tomography (CT) findings in subjects with bronchiectasis (n=155)
Bronchiectasis type Cylindric 146 (94%) Varicose 8 (5)% Cystic 1 (1%) Bronchiectasis location# Right upper lobe 19 (12%) Right middle lobe 97 (63%) Right lower lobe 81 (52%) Left upper lobe 53 (34%) Left lower lobe 62 (40%) Number of lobes with bronchiectasis¶ 1 62 (40%) 2 38 (25%) 3 26 (17%) ≥4 29 (19%) CT bronchiectasis score median (IQR) 3 (2.0–5.0) IQR: interquartile range. #: percentages do not sum to 100% as some subjects had more than one lobe involved; ¶: percentages do not sum to 100% due to rounding.
- TABLE 3
Ratio of blood vessel volume in vessels <5 mm2 in cross-section (BV5) to total blood vessel volume (TBV) by lung lobe and bronchiectasis status
Lung lobe Subjects without bronchiectasis Subjects with bronchiectasis p-value Right upper lobe 64±7 65±8 0.90 Right middle lobe 54±9 54±10 0.91 Right lower lobe 58±7 55±9 0.004 Left upper lobe 62±7 61±7 0.87 Left lower lobe 55±9 51±10 0.0008 Data are presented as mean±sd, unless otherwise stated. Results are from univariate comparisons of BV5/TBV×100 between subjects with bronchiectasis in a specific lobe only and those without bronchiectasis in any lobe. Missing values: one subject had no lobar vascular measurements and one subject had no vascular measurement in the right middle lobe.
- TABLE 4
Multivariable analysis for the differences in the ratio of blood vessel volume in vessels <5 mm2 in cross-section (BV5) to total blood vessel volume (TBV) between subjects with lower-lobe bronchiectasis and without bronchiectasis
Cohort/subcohort Difference in lower-lobe BV5/TBV se p-value Entire cohort −1.5 0.35 <0.0001 Emphysema status subcohort Subjects with emphysema −1.8 0.52 0.0008 Subjects without emphysema −1.6 0.46 0.0005 The differences in lower-lobe BV5/TBV×100 are from a multivariable regression model where the presence of lower lobes bronchiectasis is the main predictor. Analyses were adjusted for age, sex, race, pack-years smoked, forced expiratory volume in 1 s % predicted, total lung capacity determined by computed tomography % predicted, resting arterial oxygen saturation, percentage of low-attenuation areas below −950 Hounsfield units (%LAA−950) of the lower lobes and coronary artery disease. For the analysis stratified by emphysema of the lower lobes, %LAA−950 was omitted as a covariate.
- TABLE 5
Multivariable analysis for the differences in the ratio of blood vessel volume in vessels <5 mm2 in cross-section (BV5) to total blood vessel volume (TBV) between subjects with lower lobes bronchiectasis and without bronchiectasis using alternate definitions of the disease
Alternate definition Difference in lower-lobe BV5/TBV se p-value 1) Two or more bronchial paths involved Entire cohort −1.8 0.40 <0.0001 Emphysema status subcohort Subjects with emphysema −1.8 0.57 0.002 Subjects without emphysema −1.3 0.49 0.009 2) Lack of airway lumen tapering+airway seen within 1 cm of the pleura Entire cohort −2.1 0.58 0.0003 Emphysema status subcohort Subjects with emphysema −1.9 0.77 0.01 Subjects without emphysema −2.4 0.80 0.003 The differences in lower-lobe BV5/TBV×100 are from a multivariable regression model where the presence of bronchiectasis in the lower lobes is the main predictor. Analyses were adjusted for age, sex, race, pack-years smoked, forced expiratory volume in 1 s % predicted, total lung capacity determined by computed tomography % predicted, resting arterial oxygen saturation, percentage of low-attenuation areas below −950 Hounsfield units (%LAA−950) of the lower lobes and coronary artery disease. For the analysis stratified by emphysema of the lower lobes, %LAA−950 was omitted as a covariate.
Supplementary Material
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TABLE E1 Reading for bronchiectasis on 486 baseline CT scans 00044-2018_tableE1
