Healthy (n=8) | Asthma (n=26) | Significance of difference* (p value) | ||||
---|---|---|---|---|---|---|
ND (n=9) | AD (n=17) | HV vs ND | HV vs AD | ND vs AD | ||
Subject demographics | ||||||
Age years (±SD) | 34 (11) | 27 (8) | 39 (11) | 0.19 | 0.29 | 0.01 |
Male/Female | 4/4 | 2/7 | 10/7 | – | – | – |
Pulmonary function tests | ||||||
FEV1%pred (±SD) | 102 (10) | 91 (13) | 81 (14) | 0.09 | 0.001 | 0.08 |
FVC %pred (±SD) | 103 (10) | 92 (10) | 94 (11) | 0.04 | 0.06 | 0.71 |
FEV1/FVC % (±SD) | 81 (6) | 84 (7) | 69 (10) | 0.36 | 0.003 | 0.0003 |
sRaw cmH2O·s (±SD) | 2.96 (0.53) | 3.42 (1.22) | 8.51 (4.95) | 0.36 | 0.003 | 0.004 |
FeNO ppb (±SD) | 18† | 17 (9)‡ | 60 (50)§ | – | – | 0.03 |
PC20 mg/mL (±SD) | 42.3 (19.2) | 14.3 (16.8) | 1.4 (3.9) | 0.02 | <0.0001 | 0.008 |
Dyspnoea | ||||||
mMRC score (±SD) | 0.0 (0.0) | 0.7 (0.7) | 0.8 (1.0) | 0.02 | 0.04 | 0.79 |
Borg score (±SD) | 0.1 (0.2) | 0.2 (0.3) | 0.7 (0.8) | 0.28 | 0.047 | 0.12 |
3He MRI | ||||||
Whole lung VDP% (±SD) | 1.22 (0.19) | 1.31 (0.32) | 4.26 (3.28) | – | – | – |
Regional VDP% (±SD)¶ | 0.94 (0.28) | 0.95 (0.40) | 2.35 (0.98) | – | – | – |
Whole lung COV (±SD) | 0.22 (0.02) | 0.23 (0.01) | 0.26 (0.03) | 0.11 | 0.007 | 0.046 |
Regional CT¶ | ||||||
WA% (±SD) | 62 (2) | 66 (3) | 69 (3) | 0.03 | 0.001 | 0.08 |
WT% (±SD) | 24 (4) | 25 (2) | 29 (4) | 0.61 | 0.04 | 0.02 |
LA mm2 (±SD) | 18 (3) | 14 (6) | 11 (4) | 0.19 | 0.002 | 0.12 |
LA/BSA mm2/m2 (±SD) | 10 (2) | 8 (3) | 6 (2) | 0.26 | 0.0003 | 0.04 |
*Significance of difference (p<0.05) determined using a t test. All statistically significant p values are bold.
†n=1; ‡n=8; §n=13; ¶HV: n=5; ND: n=9; AD: n=9.
%pred, per cent predicted; AD, subjects with asthma with ventilation defects; BSA, body surface area; COV, coefficient of variation; FeNO, fraction of exhaled nitric oxide; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; HV, healthy volunteers; LA, lumen area; mMRC, modified Medical Research Council; ND, subjects with asthma with no ventilation defects; PC20, provocative concentration of methacholine sufficient to induce a 20% decrease in FEV1; sRaw, specific airways resistance; VDP, ventilation defect per cent; WA%, wall area per cent; WT%, wall thickness per cent.