Spirometry: FEV1 decline from baseline in the ISHLT 2019 CLAD definition

Summary

An open-access 2026 validation study (Gerckens and colleagues) restates the 2019 ISHLT definition: CLAD is a sustained loss of at least 20 percent in FEV1 from the post-transplant baseline, after other identifiable causes such as infection, airway complications or pleural effusion have been excluded and treated. In the methods of that study, baseline FEV1 was defined as the mean of the two highest post-transplant FEV1 values recorded at least 3 weeks apart, and the states were applied as follows: Potential CLAD, a single FEV1 below 90 percent of baseline; Possible CLAD, one or more values below 80 percent of baseline within 3 weeks; Probable CLAD, two or more values below 80 percent of baseline more than 3 weeks and less than 3 months apart; Definite CLAD, two or more values at or below 80 percent of baseline at least 3 months apart. These thresholds are quoted from that study as it applied the 2019 criteria; the consensus text itself was not opened. In that study 69 of its recipients were excluded from classification because they never reached a measurable baseline FEV1, and the introduction notes that baseline allograft dysfunction, defined by subnormal baseline FEV1, may predispose to earlier or more severe CLAD progression. An open-access review (Yoshiyasu and Sato 2020, as tabulated on the RAS record) describes the restrictive phenotype by a decline in total lung capacity of at least 10 percent from baseline, so spirometry alone does not distinguish phenotypes. This record describes the literature and gives no clinical advice.

Sources and links

• Gerckens et al. 2026 (open access, Europe PMC) (primary)
• Verleden et al. 2019 consensus (DOI; not opened)

Related

Links from this record

• full text opened: Prognostic validation of the 2019 International Society for Heart and Lung Transplantation chronic lung allograft dysfunction states in lung allograft recipients
• definition source (not opened): Chronic lung allograft dysfunction: Definition, diagnostic criteria, and approaches to treatment: A consensus report from the Pulmonary Council of the ISHLT
• secondary source: Chronic lung allograft dysfunction post-lung transplantation: The era of bronchiolitis obliterans syndrome and restrictive allograft syndrome
• earlier criteria: Bronchiolitis obliterans syndrome 2001: an update of the diagnostic criteria
• measures: ISHLT 2019 CLAD states: Potential, Possible, Probable and Definite
• measures: CLAD stages 0 to 4 by FEV1 relative to baseline
• used to define: Bronchiolitis obliterans syndrome (BOS)
• used to define: Restrictive allograft syndrome (RAS)

Linked from (derived)

• compares with: Intra-subject variability in oscillometry correlates with acute rejection and CLAD post-lung transplant
• affects: CLAD is recognised late and no biomarker is validated for early warning
• affects: CLAD care and measurement vary between centres

Known gaps in this record

• thresholds in the 2019 consensus text itself (not opened; values above are as applied in Gerckens 2026)
• definition of baseline allograft dysfunction in the ISHLT baseline consensus (not read)
• accuracy figures for FVC in diagnosing restrictive phenotypes (a Toronto paper by Levy 2021 was found but has no indexed abstract and was not included)