Diffusion capacity as a predictor of prognosis after onset of CLAD

Abstract

Introduction: For the diagnosis of Restrictive CLAD (rCLAD), a subtype of Chronic Lung Allograft Dysfunction (CLAD), a persistent decline in FEV1 with a concomitant decline in TLC >10% or a decline in FVC>20% is required. This study aims describe the changes in DLCo and propose a cutoff value for decline in DLCo. Methods: This is a retrospective 2 centre study comprising all double lung transplant recipients with onset of CLAD between 2010 and 2014 in Leuven and 2007-2014 in Copenhagen Including all pulmonary function variables Results: A total of 101 patients were included. 52 had BOS, 49 had rCLAD (based on either TLC and/or FVC decline). The change in DLCo from baseline to CLAd was different in the two groups with a median decline of -0.440±1.10 mmol/min/kPa in patients with BOS and a median of -1.280±1.01 mmol/min/kPa in all patients with rCLAD, p=0.006. ROC analysis demonstrated an area under the curve of 0.674 with an optimal threshold of 20% decline in DLCO. Survival after onset of CLAD stratified for DLCO decline ≥than 20% showed an impaired survival when DLCo has declined ≥20% at the onset of CLAD (p=0.012). Conclusion: This study demonstrates that recipients with rCLAD had a significantly larger decline in DLCo at the onset of CLAD compared to those with BOS. At a proposed cut-off value of 20% decline in DLCo there was an impaired survival after onset of CLAD, suggesting that the use of DLCo might be helpful diagnosing CLAD.