A major randomised trial showed no mortality difference with extracorporeal membrane oxygenation versus supportive care alone.

Respite great strides in managing acute myocardial infarction (AMI), 30­ day mortality rates remain at 40 to 50% when cardiogenic shock complicates AMI (AMI-CS). Several percutaneous devices can provide sub­stantial, temporary circulatory support to vital organs (about 3 to 5L/min blood flow). Given their relative safety and ease of insertion, short-­term circulatory support with these devices has been hypothesised to offer potential benefit in patients with AMI­-CS as cardiac function recovers.

To assess whether this approach improves survival, investigators rando­mised 420 patients (mean age, 63 years; 19% women) with AMI­-CS who were undergoing planned coronary revascula­risation (almost all with percutaneous coronary intervention) to mechanical circulatory support using extracorporeal membrane oxygenation (ECMO) or supportive care alone (NCT03637205). About 78% of participants had under­ gone cardiopulmonary resuscitation before randomisation.

The primary endpoint – all­cause mortality at 30 days – was virtually identical with ECMO (47.8%) and suppor­ tive care alone (49.0%). The ECMO group had higher rates of moderate­-to­-severe bleeding (23%, vs 10% with supportive care alone) and vascular complications requiring treatment (11% vs 4%, respec­tively). Findings were consistent across age and clinical subgroups.

Comment: These data are a sobering reminder that pathophysiological prin­ciples do not necessarily predict clinical benefit. Despite providing near­-normal cardiac output, ECMO did not improve survival in patients with AMI­-CS. Potential explanations include high rates of bleeding and vascular complications with ECMO (potentially offsetting any benefit of circu­latory support) and the fact that ECMO leads to increased cardiac afterload and ventricular volume overload, which may impair myocardial recovery. Several ongo­ing trials are testing whether a percuta­neous microaxial left ventricular assist device (which does not increase afterload) can improve survival after AMI-­CS. For now, though, we should temper enthu­siasm for use of mechanical circulatory support in these patients, given its cost, associated complications and uncertain benefit.

David J. Cohen, MD, MSc, Director of Clinical and Outcomes Research, Cardiovascular Research Foundation, New York City; Director of Academic Affairs, St. Francis Hospital, Roslyn, USA.

Thiele H, et al. for the ECLS-SHOCK Investigators. Extracorporeal life support in infarct-related cardiogenic shock. N Engl J Med 2023 Aug 26; e-pub (https://doi.org/10.1056/NEJMoa2307227).

This summary is taken from the following Journal Watch titles: Cardiology, Emergency Medicine, Hospital Medicine.