Small airway dysfunction is associated to excessive bronchoconstriction in asthmatic patients

Abstract

BackgroundWe investigated whether a relationship between small airways dysfunction and bronchial hyperresponsiveness (BHR), expressed both in terms of ease of airway narrowing and of excessive bronchoconstriction, could be demonstrated in asthma.Methods63 (36 F; mean age 42 yr ± 14) stable, mild-to-moderate asthmatic patients (FEV1 92% pred ±14; FEV1/FVC 75% ± 8) underwent the methacholine challenge test (MCT). The degree of BHR was expressed as PD20 (in μg) and as ∆FVC%. Peripheral airway resistance was measured pre- and post-MCT by impulse oscillometry system (IOS) and expressed as R5-R20 (in kPa sL−1).ResultsAll patients showed BHR to methacholine (PD20 < 1600 μg) with a PD20 geometric (95% CI) mean value of 181(132–249) μg and a ∆FVC% mean value of 13.6% ± 5.1, ranging 2.5 to 29.5%. 30 out of 63 patients had R5-R20 > 0.03 kPa sL−1 (>upper normal limit) and showed ∆FVC%, but not PD20 values significantly different from the 33 patients who had R5-R20 ≤ 0.03 kPa sL−1 (15.8% ± 4.6 vs 11.5% ± 4.8, p < 0.01 and 156(96–254) μg vs 207 (134–322) μg, p = 0.382). In addition, ∆FVC% values were significantly related to the corresponding pre- (r = 0.451, p < 0.001) and post-MCT (r = 0.376, p < 0.01) R5-R20 values.ConclusionsOur results show that in asthmatic patients, small airway dysfunction, as assessed by IOS, is strictly associated to BHR, expressed as excessive bronchoconstriction, but not as ease of airway narrowing.

Usefulness of impulse oscillometry for the assessment of airway hyperresponsiveness in mild-to-moderate adult asthma

“…12,13 In line with previous studies, 12 the authors found significant effects on small airway measurements (R5eR20) during standardized bronchial challenge testing. Small airway dysfunction within asthma is becoming recognized as a distinct clinical phenotype associated with poor asthma control.…”

Association of FEF25-75% Impairment with Bronchial Hyperresponsiveness and Airway Inflammation in Subjects with Asthma-Like Symptoms

“…Small airways disease, assessed by peripheral airway resistance, has recently been associated with excessive bronchoconstriction in asthmatic patients [42]. Our data support the role of FEF 25-75% as a marker of early airway obstruction and as a risk factor for BHR positivity and severity in agreement with previous reports on allergic [43,44,45] and rhinitic subjects [10]; therefore, in clinical practice a more rational approach should also include measurements of FEF 25-75% [46].…”

Small airway dysfunction and bronchial asthma control : the state of the art

“…Furthermore, ΔFVC% correlated to asthma treatment in adult patients and to the presence of symptoms in children with asthma [98, 99]. Recently, Alfieri et al provide the first evidence that in asthmatic patients excessive bronchoconstriction expressed by ΔFVC% is strictly associated to small airway dysfunction, as assessed by IOS [100]. As compared to patients with R5–R20 ≤ 0.030 kPa s l −1 , patients with R5–R20 > 0.030 kPa s l −1 had a high likelihood to be associated to a ΔFVC% greater than 14.5 % during a methacholine-induced bronchoconstriction.…”