Effect of Peripheral VA-ECMO Flow Variations on the Pulmonary Arterial Occlusion Pressure (PAPO) in Patients With Refractory Cardiogenic Shock.

This study focuses on a population of adult patients placed under peripheral Veno-Arterial Extracorporeal Membrane Oxygenation (VA-ECMO) for refractory cardiogenic shock. Cardiogenic shock, primarily caused by myocardial infarction, is associated with a high mortality rate that remains around 50%, despite advancements in the field of coronary reperfusion. VA-ECMO is a rapidly growing cardiac support technique worldwide. Its goal is to improve peripheral organ perfusion even as myocardial damage continues, thereby enhancing the prognosis of patients with severe multiorgan failure. VA-ECMO is a temporary cardio-respiratory support technique based on the principle of extracorporeal circulation. However, patients under VA-ECMO are at risk of experiencing various complications, including infectious, thromboembolic, hemorrhagic complications, or malfunctions of the ECMO machine itself, with the incidence increasing with the duration of assistance. Numerous authors and scientific reviews highlight the increased risk of Acute Pulmonary Edema (APE) in patients under peripheral VA-ECMO, attributing it to the elevation of afterload induced by retrograde arterial reinfusion against the residual native blood flow, hypothetically leading to an increase in Pulmonary Artery Occlusion Pressure (PAOP). This phenomenon is presumed to intensify as the VA-ECMO reinfusion rate increases. Furthermore, APE under ECMO-VA represents a turning point in the patient's course. Brechot et al. demonstrated that patients who developed APE under VA-ECMO had a prolonged ECMO duration, a higher reliance on mechanical ventilation, an extended stay in critical care, and a higher mortality rate compared to patients who had previously undergone a left ventricular unloading technique (aimed at reducing PAOP and the risk of APE). However, until now, no physiological study has assessed the specific effect of the variation in peripheral VA-ECMO flow on the change in PAOP during a dedicated protocol. It is w