Immediate Use of ECMO Did Not Improve Outcomes in Patients with Cardiogenic Shock

Petr Ostadal, MD, PhD

The immediate implementation of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) in adults with rapidly deteriorating or severe cardiogenic shock was not associated with improved clinical outcomes compared with no immediate VA-ECMO, according to new findings.

The research indicated a substantial proportion (39%) of patients in the early conservative therapy group required VA-ECMO at a later point during their hospital stay, due to further hemodynamic deterioration.

“We expected to see a significant improvement in outcomes for patients with severe or rapidly progressing cardiogenic shock who underwent early ECMO treatment, and we were surprised to find that immediate use of ECMO was actually not superior to early conservative therapy,” said study author Professor Petr Ostadal, MD, PhD, Cardiovascular Center, Na Homolce Hospital in an accompanying press release.

The findings were presented in a late-breaking session at the American Heart Association Scientific Sessions 2022 in Chicago.

Advances have been made in cardiovascular acute and intensive care, but early mortality from cardiogenic shock still remains high. Clinicians are increasingly using ECMO in patients with severe circulatory collapse, as it can provide full circulatory support.

The objective of the Extracorporeal Membrane Oxygenation in the Therapy of Cardiogenic Shock (ECMO-CS) trial was to consider the immediate implementation of VA-ECMO against an initially conservative strategy. It is the first multicenter, randomized clinical trial focused on the use of ECMO in patients with severe or rapidly progressing cardiogenic shock.

The randomized, investigator-initiated, academic clinical trial was conducted at four centers in the Czech Republic. Patients were eligible for randomization if they had rapidly deteriorating or severe cardiogenic shock and those who fulfilled trial entry criteria were randomly assigned in a 1:1 ratio of immediate VA-ECMO or early conservative therapy.

Standard of care was provided for those in the early conservative group, but VA-ECMO was allowed downstream in the case of worsening hemodynamic status. The primary trial endpoints were the composite of death from any cause, resuscitated circulatory arrest, and implementation of another mechanical circulatory support at 30 days.

A total of 122 patients were randomized between September 2014 and January 2022. After exclusion of 5 patients due to the absence of informed consent, the study included 58 subjects to the immediate VA-ECMO group and 59 subjects to the no immediate VA-ECMO.

Data show the composite primary endpoint occurred in 37 (63.8%) patients in the immediate VA-ECMO group and 42 (71.2%) in the early conservative group. The Kapaln-Meier probability estimate at 30 days was reported as 68.9% in the immediate VA-ECMO group and 71.8% in the early conservative group (hazard ratio [HR], 0.72; 95% confidence interval [CI], 0.46 to 1.12; P = .21).

Moreover, the all-cause mortality at 30 days was comparable between the two groups (50.0% vs. 47.5%; HR, 1.110; 95% CI, 0.660 to 1.866). Serious adverse events, including bleeding, leg ischemia, stroke, pneumonia and sepsis was reported to have occurred in 60% of individuals in the ECMO group and 61% in the early conservative group.

Investigators observed fewer patients in the ECMO group required another form of mechanical circulatory support when compared to those in the early conservative group (17% vs. 42%, respectively). The findings indicate 23 (39%) patients in the early conservative required downstream VA-ECMO support, of whom 12 (52.2%) died.

The reported limitations of the study included the lack of comparison of VA-ECMO with conversative therapy, but instead, its comparison of immediate VA-ECMO with early conservative strategy permitting “bail-out” VA-ECMO therapy in the case of worsening hemodynamic status. Investigators suggested the results should “be interpreted accordingly” as a result.

The study, “Extracorporeal Membrane Oxygenation in the Therapy of Cardiogenic Shock: Results of the ECMO-CS Randomized Clinical Trial,” was published in Circulation.