Clinical Relevance of Platelet-Leukocyte Aggregates and Platelet P-Selectin Expression During Venovenous Extracorporeal Membrane Oxygenation

Thrombosis continues to be a significant complication during venovenous extracorporeal membrane oxygenation (V-V ECMO). Platelet activation markers might serve as indicators of inflammation and thrombogenesis. The aim was to identify these markers in ECMO patients. Blood from 10 ECMO patients (before, during, after ECMO) and 11 healthy volunteers were collected to determine platelet-neutrophil-aggregates (PNAs), platelet-monocyte-aggregates (PMAs), fibrinogen-binding, and P-selectin-expression on platelets by flow cytometry. Critical illness was associated with significantly elevated levels of PNAs and PMAs, increased P-selectin expression, reduced fibrinogen-binding, and restricted activation of platelets. Although PNAs and PMAs decreased significantly within 2 hours after the initiation of ECMO and remained at those levels, ECMO did not affect basal P-selectin expression and fibrinogen-binding. These results correlated with coagulation activation. Platelet markers before ECMO were not indicators for an imminent system exchange and end of therapy. In conclusion, platelet dysfunction during ECMO was mainly attributed to the critical illness. Extracorporeal membrane oxygenation support strengthened the restricted response of platelets to exogenous agonists (P-selectin). Furthermore, a decrease in PNAs/PMAs after ECMO started identified a reduced inflammatory response. There was no correlation of analyzed platelet parameters with the incidence of thrombotic complications.