Microvesicles Are Associated with Early Veno Venous ECMO Circuit Change during Severe ARDS: A Prospective Observational Pilot Study.

Background: Veno venous Extra Corporeal Membrane Oxygenation (vvECMO) is associated with frequent hematological ECMO-related complications needing ECMO circuit change. Microvesicles (MVs) interplay during the thrombosis-fibrinolysis process. The main objective of the study was to identify subpopulations of MVs associated with indications of early vvECMO circuit change.
Methods: This is a prospective observational monocenter cohort study. Blood gas was sampled on the ECMO circuit after the membrane oxygenator to measure the PO _{2 post oxy} at inclusion, day 3, day 7 and the day of ECMO circuit removal. Blood samples for MV analysis were collected at inclusion, day 3, day 7 and the day of ECMO circuit removal. MV subpopulations were identified by flow cytometry.
Results: Nineteen patients were investigated. Seven patients (37%) needed an ECMO circuit change for hemolysis (n = 4), a pump thrombosis with fibrinolysis (n = 1), persistent thrombocytopenia with bleeding (n = 1) and a decrease of O ₂ transfer (n = 1). Levels of leukocyte and endothelial MVs were significantly higher at inclusion for patients who thereafter had an ECMO circuit change ( p = 0.01 and p = 0.001). The areas under the received operating characteristics curves for LeuMVs and EndoMVs sampled the day of cannulation and the need for ECMO circuit change were 0.84 and 0.92, respectively. PO _{2 post oxy} did not significantly change except for in one patient during the ECMO run.
Conclusions: Our pilot study supports the potential interest of subpopulations of microvesicles early associated with hematological ECMO-related complications. Our results warrant further studies.