Title : Heroic measures: Mechanical circulatory support with VA-ECMO in acute MI complicated by cardiogenic shock
Abstract:
Cardiogenic shock in the context of acute myocardial infarction (AMI-CS) remains a highly morbid presentation with high associated mortality, despite significant advances in early institution of reperfusion and multiple available modalities for mechanical circulatory support. Contemporary trials of cardiogenic shock complicating AMI continue to demonstrate mortality greater than 40% in this patient population. Rapid institution of hemodynamic support veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has shown promise in multiple registry settings but with mixed results in randomized trials for attenuating myocardial damage and improving survival in this patient population. Most recently VA-ECMO was evaluated in the ECLS-Shock Trial, a randomized investigation of this support modality in the AMI-CS population, without demonstration of a mortality benefit and with some increase in bleeding complications. Demonstrating the efficacy of this complex modality in the inherently heterogenous population of shock patients is a challenge. More precise profiling of patient inclusion criteria using the frame work of the SCAI Cardiogenic Shock stages has led to progress in trial design but remains limited due to staging being performed at one time stamp, while shock is often a progressive and evolving state. Additional variables include institution of VA-ECMO during cardio-pulmonary resuscitation (termed E-CPR), versus prior to revascularization therapy, versus post-revascularization. VA-ECMO is fraught with several complications unique to this modality of mechanical circulatory support including imposed high left ventricular afterload, paradoxical emboli and cerebrovascular accidents, pulmonary vasculature thrombosis and hemorrhage, and Harlequin syndrome resulting from poorer perfusion to upper extremities and coronary and cerebral circulation compared to lower extremities that are supplied by the ECMO circuit.
The physiology, unique challenges of implementation, complications and randomized data for the use of VA-ECMO for AMI-CS will be reviewed. The mechanisms for LV off-loading or venting while on ECMO support will also be reviewed.
Audience Take Away:
- Review the historical development of ECMO technology
- Delineate the physiology of the VA-ECMO circuit
- Understand the complications unique to VA-ECMO technology
- Review the data supporting VA-ECMO for AMI-CS
- Delineate a workflow to select the optimal LV unloading strategies for patients on VA-ECMO support
- Determine algorithms to select patients most likely to benefit from robust MCS with VA-ECMO
