PT - JOURNAL ARTICLE AU - A Fu AU - A Vasileva AU - N Hanafi AU - N Belousova AU - J Wu AU - S S Rajyam AU - Z Hantos AU - C Chow TI - Characterization of chronic lung allograft dysfunction phenotypes using oscillometry AID - 10.1183/13993003.congress-2022.4370 DP - 2022 Sep 04 TA - European Respiratory Journal PG - 4370 VI - 60 IP - suppl 66 4099 - http://erj.ersjournals.com/content/60/suppl_66/4370.short 4100 - http://erj.ersjournals.com/content/60/suppl_66/4370.full SO - Eur Respir J2022 Sep 04; 60 AB - Background: Chronic lung allograft dysfunction (CLAD) is the major cause of death beyond 2 years after lung transplantation (LTx). Of the two main phenotypes: bronchiolitis obliterans syndrome (BOS) is more common and has a better prognosis than restrictive allograft syndrome (RAS). Oscillometry (Osc) is highly sensitive to lung mechanics. The current study investigated whether spectral and intrabreath Osc can differentiate between CLAD-free, BOS- and RAS-CLAD.Methods: A retrospective, cross-sectional analysis of 289 double LTx recipients from 2017 to 2021 was conducted. Osc was performed and CLAD was diagnosed according to international guidelines. Statistical analysis was conducted using multiple comparisons.Findings: CLAD-free (n=182), BOS (n=28), and RAS (n=6) have different spectral Osc patterns, with BOS and RAS resembling obstructive and interstitial lung disease respectively. Spectral Osc measurements were significantly different between the CLAD and time-matched CLAD-free patients (p<0.05 for all). Post-hoc analysis showed the differences were primarily due to the BOS patients. Intrabreath Osc was also significantly different between the CLAD and CLAD-free patients. In contrast to spectral Osc where no differences were found between CLAD-free and RAS-CLAD, the intrabreath metric of reactance at end-inspiration (XeI) was significantly different between the 2 groups (p=0.015).Conclusions: While both spectral and intrabreath Osc can differentiate CLAD and CLAD-free, intrabreath Osc, specifically XeI, can uniquely distinguish RAS-CLAD from CLAD-free. XeI is a biomarker that could be used for the early identification of RAS.FootnotesCite this article as Eur Respir J 2022; 60: Suppl. 66, 4370.This article was presented at the 2022 ERS International Congress, in session “-”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).