Endothelial injury is usually considered as a major com-ponent of the systemic inflammatory response observed during veno-arterial extracorporeal membrane oxygena-tion (VA-ECMO) support. Yet, few data are avail-able to support this common belief, mostly inferred from observations in trauma, sepsis or cardiac surgery patients. Better characterization of endothelial injury during ECMO support is essential to understand the pathophysiological mechanisms underlying organ injury, to identify new therapeutic targets, or to develop pre-vention strategies. The main objective of this pilot study was to evaluate the extent of endothelial injury within the first 72h after VA-ECMO initiation in patients with refractory non-surgical cardiogenic shock (CS). We hypothesized that VA-ECMO would be associated with significant endothelial injury.