Biomolecular Phenotyping of Lung Transplant Recipients: a Prospective Observational Study

Primary graft dysfunction (PGD) is the most common complication after lung transplant (LUTX). PGD is an acute form of lung injury with an incidence of 30%, defined upon alteration of oxygenation and radiographic criteria occurring <72 hours after graft reperfusion.

The PGD definition does not consider the heterogeneity of clinical manifestations of ischemia-reperfusion (I/R) injury. First, PGD severity may vary from mild radiographic signs to life-threatening lung injury. Second, duration may differ: most patients manifest transient hypoxia, but a minority have persistent respiratory failure. Finally, PGD is associated with hemodynamic and renal failure, suggesting that it might be considered a heterogeneous syndrome characterized by multisystemic widespread endothelial barrier damage and inflammation activation due to I/R injury rather than an alteration of the sole lung function.

Following the new paradigm of precision medicine, the investigators hypothesize that predictive enrichment may allow for detecting different - and potentially treatable - traits (i.e., hypo vs. hyperinflammatory) of PGD and applying targeted treatments to sub-cohorts. As for other critical illnesses (i.e., acute respiratory distress syndrome - ARDS, sepsis), the investigators envision the possibility of carrying out biological subtyping of LUTX patients to select the patients with the lowest chance of harm for treatment. In the similar -but not equivalent- context of ARDS, it has been proven that treatments (e.g., positive end-expiratory pressure, fluid management, simvastatin) that disappointingly failed to benefit the overall patients' population provided benefit in specific patients' subcohorts. Biological phenotyping of LUTX recipients has never been carried out, and literature is ample but sparse regarding early PGD plasmatic biomarkers.

With this prospective observational study, the investigators aim to assess: 1/ whether LUTX recipients can be clustered based on early plasma concentration of biomarkers of inflammation, coagulation, and endothelial activation, and 2/ whether these clusters could be associated with clinical outcomes (and specifically PGD).