Chronic lung allograft dysfunction

Chronic lung allograft dysfunction (CLAD) is one of the late-stage post lung transplant complications. It is a clinical spirometric diagnosis characterized by an irreversible decline in the FEV1 of 20% or more relative to the highest post-transplant baseline representing one of the significant limitations in the survival of post-lung transplant patients. It is considered an umbrella term that encompasses two different phenotypes:

• obstructive, which represents the bronchiolitis obliterans syndrome (BOS) with a picture of small airway obstruction
  • on imaging (HRCT), the major finding would be the presence of mosaic attenuation pattern and air trapping on an expiratory acquisition
• restrictive, also termed as restrictive allograft syndrome (RAS) or rCLAD, clinically showing restrictive functional lung changes due to a fibrotic process
  • on imaging (HRCT), it demonstrates persistent pleuroparenchymal infiltrates associated with marked lung volume loss compared to the baseline scans

These two phenotypes may evolve one to another along the post-transplant period .