Veno-arterial extracorporeal membrane oxygenation for acute myocardial infarction-associated cardiogenic shock: can we predict survival before decision of implantation?

Acute myocardial infarction (AMI) with subsequent ventricular dysfunction is the most frequent cause of cardiogenic shock (CS) accounting for about 80% of cases (1). CS remains the leading cause of death in AMI with mortality rates still approaching 40–50% (2,3). The treatment of AMI-induced CS principally consists of early revascularization and intensive care treatment with inotropes, vasopressors, sedation and mechanical ventilation. The most severe cases of CS can be treated with mechanical circulatory support, as a bridge to recovery of cardiac function, or sometimes as a bridge to heart transplantation. According to Guidelines of the European Society of Cardiology (4), short-term mechanical circulatory support should be considered (as a ‘bridge to recovery’) in patients remaining severely hypoperfused despite inotropic therapy and with a potentially reversible cause (e.g., viral myocarditis) or a potentially surgically correctable cause (e.g., acute interventricular septal rupture) (class IIa/level C recommendation) and may be considered (as a ‘bridge to decision’) in patients deteriorating rapidly before a full diagnostic and clinical evaluation can be made (class IIb/level C recommendation). Among available devices, veno-arterial (VA)-Extracorporeal Membrane Oxygenation (ECMO) technique, also called Extracorporeal Life Support (ECLS), has been increasingly used (5) since it is easy to implant in referring centers and has an acceptable cost. Main limitations of these devices are large cannula sizes potentially causing lower limb ischaemia and bleeding complications, lack of direct left-ventricular unloading, rise in afterload, and a limited support time. In a recent meta-analysis including 20 studies and 1,866 patients, complications were frequent with lower extremity ischaemia (16.9%), compartment syndrome (10.3%), amputation (4.7%), stroke (5.9%), major bleeding (40.8%), and significant infection (30.4%) (6). To date, there are no randomized controlled trials comparing ECMO with other mechanical support systems in AMI-associated CS, but several nonrandomized studies suggest a survival advantage from the early use of ECMO in such circumstances. In a previous observational study conducted in 81 patients given ECMO support for medical (n=55), postcardiotomy (n=16), or posttransplantation (n=10) CS, Combes et al. (7) found that independent predictors of intensive care unit (ICU) death were device insertion under cardiac massage [odds ratio (OR) =20.68], 24 h urine output <500 mL (OR =6.52), prothrombin activity <50% (OR =3.93), and female sex (OR