To the Editor: In patients with severe refractory cardiogenic shock (CS), mechanical circulatory support is recommended by guidelines to restore critical end-organ perfusion (1). Despite its increasing use, survival of venoarterial extracorporeal membrane oxygenation (VA-ECMO) patients remains dismal at 45%, and no randomized clinical trial has shown improved patient outcomes relative to other strategies. Multiorgan dysfunction remains the primary cause of death in CS supported by VA-ECMO, intensified by a systemic inflammatory response that exacerbates microcirculatory dysfunction (2). Pulsatile flow (PF) VA-ECMO has been shown to increase hemodynamic energy production, which is associated with improved microcirculatory perfusion (3). However, inference from previous evidence is limited by the use of healthy animals and lack of reproducibility, with no previous study investigating sublingual microcirculation using animal models of CS, hindering the translatability of efficacy and safety data into the clinical scenario. In a prospective, randomized, single-blind preclinical trial, we aimed to compare the effects of PF versus continuous flow (CF) VA-ECMO on sublingual microcirculation.