Dual Antiplatelet Therapy (DAPT) with acetylsalicylic acid (ASA) and oral P2Y12 inhibitor (Clopidogrel, Ticagrelor or Prasugrel) is recommended in STEMI or NSTEMI patients undergoing primary Percutaneous Coronary Intervention (PCI). There is evidence for an increased risk of stent thrombosis after PCI despite administration of DAPT in patients resuscitated from a cardiac arrest with STEMI/NSTEMI who undergo primary PCI, in particular for those treated with hypothermia. Point of Care Aggregometry represents an emerging tool to measure platelet reactivity in patient treated with antiplatelets drugs. Among patients with Acute Coronary Syndrome (ACS), those requiring Veno-Arterial Extracorporeal Membrane Oxygenation (VA-ECMO) for refractory Cardiogenic Shock or Cardiac Arrest represent a growing population burdened by more profound metabolic, pharmacokinetic, hemostatic and physiological alterations due to increased clinical severity and ECMO itself. In addition, profound platelet inhibition can result in a higher risk of bleeding complication, since these patients have to be simultaneously anticoagulated with unfractioned heparin (UFH) and ECMO itself can cause coagulopathy. We aimed to perform an observational prospective cohort study to investigate platelet reactivity in a population of ACS patients with different clinical severity.