The current European Society of Cardiology (ESC) guidelines for cardiogenic shock (CS) management recommend using Oxygen for early hemodynamic stabilization (Class I recommendation).¹ The guidelines also stated that ventilatory support, administration of inotropes, and vasopressors should be considered for Class IIa and Class IIb recommendations, respectively; while short-term mechanical circulatory support (MCS) should be considered for Class IIa recommendation.¹ Yet, there is still inadequate data to justify the immediate usage of extracorporeal membrane oxygenation (ECMO) as an MCS in this regard.¹ Therefore, the ECMO-CS trial has been conducted to investigate if a less aggressive initial approach, early conservative therapy using inotropes and vasopressors, maybe effective for patients with CS by comparing it with immediate ECMO implantation in patients having rapidly deteriorating or severe CS.¹ Dr. Petr Ostadal from the Na Homolce Hospital of the Czech Republic presented the results in the American Heart Association (AHA) Scientific Sessions 2022.¹ 

ECMO-CS was a multicenter, randomized, investigator-initiated, academic clinical trial, with no industry participation.¹ The trial enrolled participants from September 2014 to January 2022.¹ Patients with rapidly deteriorating CS corresponding to the Society for Cardiovascular Angiography and Interventions (SCAI) stage D-E, with evidence of cardiac pump failure and required repeated bolus of vasopressors to maintain a mean arterial pressure (MAP) >50mmHg; or patients with severe CS corresponding to SCAI stage D, with evidence of pump failure even with high doses of inotropes and vasopressors, evidence of tissue hypoperfusion and exclusion of hypovolemia were included in the trial.¹ The eligible patients were randomized 1:1 to receive either immediate ECMO implantation (n=58) or early conservative therapy (n=59).¹ Patients in the conservative arm were allowed to have ECMO in case of hemodynamic worsening, which was defined by a rise of lactate by 3mmol/L.¹

The primary outcome was a composite of all-cause mortality, resuscitated circulatory arrest, or the use of a different MCS (including ECMO in the conservative arm) at day 30.¹ The baseline characteristics between the 2 arms were well-balanced.¹ There was no difference between the 2 groups in the primary composite endpoint (HR=0.72; 95% CI: 0.46-1.12; p=0.21).¹ The incidence of the primary composite endpoint was 63.8% in the immediate ECMO arm and 71.2% in the conservative arm.¹ There was no difference in death from any cause and resuscitated cardiac arrest between the 2 arms (50% vs. 47.5%; 10.3% vs. 13.6%).¹ Fewer patients in the immediate ECMO arm required another MCS compare with the conservative arm (17.2% vs. 42.4%).¹ Downstream ECMO in the early conservative arm was required in 39% of the cases.¹ The overall serious adverse events (SAEs) were comparable in the 2 arms (60.3% in the immediate ECMO arm vs. 61.0 % in the conservative arm). There was no significant difference between the 2 arms in the incidence of bleeding, leg ischemia, stroke, pneumonia, and sepsis.¹ When the analysis of the primary endpoint was done based on the types of shock, it was surprising to find that there were lower incidences in the rapidly deteriorating patient group (60.0%) compared with patients in the severe CS group (72.2%). Similarly, the incidences of all-cause death were lower in the rapidly deteriorating patient group (40.0%) compared with patients in the severe CS group (54.4%).¹ However, there was no difference in these outcomes where either the immediate ECMO or conservative strategy was used.¹ 

In conclusion, for patients with rapidly deteriorating or severe CS, immediate ECMO implantation did not enhance the clinical outcomes as compared with an early conservative strategy that allowed for the downstream use of ECMO in the event of hemodynamic deterioration.¹ Although it was observed that a significant percentage of patients on the conservative treatment required the downstream use of ECMO or another MCS because of the deterioration of their hemodynamic state, the early hemodynamic stabilization with inotropes and vasopressors followed by MCS only, if hemodynamic deterioration persists, could be a treatment strategy comparable to immediate ECMO insertion, even in patients with rapidly deteriorating or severe CS (i.e., SCAI stage D-E).¹