Chronic Lung Allograft Dysfunction: More Than Meets the Eye?

• Published in: The Journal of heart and lung transplantation Vol. 41; no. 4; p. S288
• Main Authors: Beeckmans, H., Sacreas, A., Vanstapel, A., Kaes, J., Geudens, V., Bart, V.M., Bos, S., Van Slambrouck, J., Orlitova, M., Ceulemans, L.J., Van Raemdonck, D.E., Neyrinck, A.P., Dupont, L.L., Godinas, L., Verleden, G.M., Vos, R.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.04.2022
• ISSN: 1053-2498; 1557-3117
• DOI: 10.1016/j.healun.2022.01.708

Currently, chronic lung allograft dysfunction (CLAD) is defined as the presence of an irreversible or partly reversible (to ≤ 80% of baseline) decline in FEV1 compared with baseline FEV1 values, persistent for at least 3 months. In established CLAD, total lung capacity (TLC) and chest computed tomography (CT) are required to determine the CLAD phenotype, as this has therapeutic and prognostic significance. Current CLAD phenotypes comprise bronchiolitis obliterans syndrome (BOS), restrictive allograft syndrome (RAS), Mixed, or Undefined (in patients who do not fit in either of the other phenotypes). However, some patients may present with persistent (> 3 months) chest CT abnormalities suggestive for chronic lung allograft injury/remodelling, without clear spirometric evidence of physiologic lung allograft impairment. We report a series of 7 lung transplant recipients demonstrating chronic radiological abnormalities comparable to that seen in CLAD (RAS/mixed), after exclusion of other underlying causes for the observed radiological abnormalities, yet without (significant) pulmonary function decline. All patients had clear, persistent (> 3 months) radiological signs of chronic lung allograft injury/remodelling, however, not qualifying for formal CLAD diagnosis (i.e. FEV1 decline ≥ 20% from baseline), but instead looming in the potential CLAD area (FEV1 decline ≥ 10% from baseline) or even presenting with normal spirometry on regular pulmonary function testing. A subgroup of lung transplant recipients may atypically present with chronic parenchymal/interstitial (‘RAS-like’) abnormalities on chest CT, without qualifying for the phenotypic definition of CLAD, according to current consensus. This warrants further reflection on the role of spirometry for detection of interstitial lung disease after lung transplantation, the potential need for regular chest CT during post-transplant follow-up, and accuracy of the current CLAD definition regarding physical lung allograft characteristics.