Mechanical circulatory support (MCS) is increasingly utilized as a means of hemodynamic support among cardiogenic shock (CS) patients refractory to optimal medical management. MCS modalities include using either an intra-aortic balloon pump (IABP), Impella®, or ECMO, each with unique benefit/harm profiles. Among the various MCS devices, extracorporeal membrane oxygenation (ECMO) is described as the highest level of support, capable of providing 5+ liters per minute of oxygenated blood flow but is the most invasive. Despite the benefit of maximal cardiopulmonary support, ECMO increases afterload in a failing heart. Left ventricular (LV) unloading or decompression (using simultaneous IABP or Impella®) has been suggested as potential improvement. Observational studies suggest a benefit with LV unloading during VA ECMO for CS, but the mechanisms underlying the association are poorly understood. Prior to trials, a mechanistic understanding of the effect of different LV unloading strategies on key physiologic abnormalities in CS is needed, as the physiologic effects of LV unloading during VA ECMO for CS remain insufficiently defined.~The objective of this study is to define serial changes in common clinical variables routinely obtained during management of patients in CS. These clinical variables are readily accessible to clinicians, but are not typically collected in a sufficiently granular serial manner to characterize their utility as clinical biomarkers. By obtaining scheduled assessments, repeated in a prospective cohort over the clinical course of CS, the investigators will define the physiologic effects of different LV unloading strategies in cardiogenic shock. We will examine a) echocardiographic measures of ventricular distension, and b) blood biochemical measures of peripheral perfusion.
Aim 1: Prospective, observational analysis of the association between echocardiographic measures of cardiac function and left ventricular unloading on VA ECMO.~Aim 2: Prospective, observational analysis of the association between clinical laboratory biomarkers and left ventricular unloading on VA ECMO.