Small airway dysfunction is associated to excessive bronchoconstriction in asthmatic patients

Research

Veronica Alfieri¹, Marina Aiello¹, Roberta Pisi¹, Panagiota Tzani¹, Elisa Mariani¹, Emilio Marangio¹, Dario Olivieri¹, Gabriele Nicolini² and Alfredo Chetta^1*

• *Corresponding author: Alfredo Chetta chetta@unipr.it

Author Affiliations

¹Clinical & Experimental Medicine Department, University of Parma, Padiglione Rasori, via G. Rasori 10, Parma, 43125, Italy

²Corporate Clinical Development, Chiesi Farmaceutici S.p.A, Parma, Italy

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Respiratory Research 2014, 15:86  doi:10.1186/s12931-014-0086-1

The electronic version of this article is the complete one and can be found online at:http://respiratory-research.com/content/15/1/86

Received:	1 April 2014
Accepted:	20 July 2014
Published:	27 August 2014

© 2014 Alfieri et al.; licensee BioMed Central Ltd. 

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Abstract

Background

We 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.

Methods

63 (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).

Results

All 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 PD₂₀values 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.

Conclusions

Our 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.

Keywords: 

Bronchial hyperresponsiveness; Small airways; Asthma

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