A panel of lung injury biomarkers enhances the definition of primary graft dysfunction (PGD) after lung transplantation

BACKGROUND: We aimed to identify combinations of biomarkers to enhance the definition of PGD for translational research. METHODS: Biomarkers reflecting lung epithelial injury (sRAGE and SP-D), coagulation cascade (PAI-1 and Protein C), and cell adhesion (ICAM-1) were measured in the plasma of 315 subjects derived from the LTOG cohort at 6 and 24 hours after transplantation. We assessed biomarker utility in two ways: first, we tested the discrimination of grade 3 PGD within 72 hours; second, we tested the predictive utility of plasma biomarkers for 90-day mortality. RESULTS: 86/315 subjects (27%) developed PGD. 23 subjects (8%) died within 90 days of transplantation, of which 16 (70%) had PGD. Biomarkers measured at 24 hours had greater discrimination than at 6 hours. Individually, sRAGE (AUC 0.71) and PAI-1 (AUC 0.73) had the best discrimination of PGD. The combinations of sRAGE with PAI-1 (AUC 0.75), PAI-1 with ICAM-1 (AUC 0.75), and PAI-1 with SP-D (AUC 0.76) had the best discrimination. Combinations of greater than 2 biomarkers did not significantly enhance discrimination of PGD. ICAM-1 with PAI-1 (AUC 0.72) and ICAM-1 with sRAGE (AUC of 0.72) had the best prediction for 90-day mortality. The addition of ICAM-1, PAI-1, or sRAGE to the concurrent clinical PGD grade significantly improved prediction of 90-day mortality (p<0.001 each). CONCLUSIONS: Measurement of the combination of a marker of impaired fibrinolysis with an epithelial injury or cell adhesion marker had the best discrimination for PGD and prediction for early mortality, and may provide an alternative outcome useful in future research