title: Air trapping is a major determinant of persistent airway obstruction in asthmatics.
abstract: Chronic persistent airway obstruction has been observed in moderate-to-severe asthmatics despite treatment with inhaled corticosteroids. We investigated which airway changes were associated with this obstruction. High-resolution computed tomography (HRCT) was performed at study entry and reexamined at the time of follow-up when the FEV1 reached a maximally constant level after treatment for 1 year or more with inhaled corticosteroids. Bronchial wall area and air trapping extent were compared in the recovered group (n = 18) and the persistent airway obstruction group (n = 14). Bronchial wall area and air trapping of the initial HRCT were similar between the two groups. On follow-up HRCT, air trapping was markedly decreased in the recovered group compared with that on initial HRCT (P = 0.017), whereas bronchial wall area did not change. In the persistent-airway-obstruction group, these two parameters did not change during follow-up. When follow-up HRCT was compared, air trapping was significantly greater in the persistent-airway-obstruction group than in the recovered group (P = 0.003). Difference post-bronchodilator FEV1 value between at initial and 2nd HRCT exam was correlated with difference air trapping value between at initial and 2nd HRCT exam(%) on the follow-up HRCT (P = 0.017). The presence of persistent airflow obstruction were significantly associated with the air trapping % difference between initial and 2nd time (RR = 1.70, P = 0.018). Persistence of AT could be a main contributing factor to chronic persistent airflow obstruction in asthma.
authors.affiliation: Genome Research Center for Allergy and Respiratory Disease, Soonchunhyang University Bucheon Hospital, 1174, Jung-Dong, Wonmi-Gu, Bucheon, Gyeonggi-Do 420-020, South Korea.
authors.forename: Sung-Woo
authors.initials: SW
authors.lastname: Park
authors.forename: Jai-Soung
authors.initials: JS
authors.lastname: Park
authors.forename: Sun Hye
authors.initials: SH
authors.lastname: Jeong
authors.forename: Yun Nah
authors.initials: YN
authors.lastname: Lee
authors.forename: Young
authors.initials: Y
authors.lastname: Hwangbo
authors.forename: Jong Sook
authors.initials: JS
authors.lastname: Park
authors.forename: June Hyuk
authors.initials: JH
authors.lastname: Lee
authors.forename: An-Soo
authors.initials: AS
authors.lastname: Jang
authors.forename: Do-Jin
authors.initials: DJ
authors.lastname: Kim
authors.forename: Soo Taek
authors.initials: ST
authors.lastname: Uh
authors.forename: Yong Hoon
authors.initials: YH
authors.lastname: Kim
authors.forename: Choon-Sik
authors.initials: CS
authors.lastname: Park
mesh_terms: D000280:Administration, Inhalation; D000368:Aged; D001249:Asthma / Q000150:complications* / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume / Q000502:physiology; D005938:Glucocorticoids / Q000008:administration & dosage / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000209:etiology* / Q000503:physiopathology; D012129:Respiratory Function Tests; D014057:Tomography, X-Ray Computed / Q000379:methods; D014797:Vital Capacity / Q000502:physiology
chemical_list: D005938:Glucocorticoids