Upfront ECMO Disappoints for Cardiogenic Shock

CHICAGO -- Unexpectedly, early extracorporeal membrane oxygenation (ECMO) did not help outcomes in severe or rapidly progressing cardiogenic shock, the ECMO-CS randomized trial found.

What appeared to be an early benefit in the first few days ultimately turned into a null clinical result at 30 days, when the combined endpoint of all-cause death, resuscitated circulatory arrest, or implementation of another mechanical circulatory support (MCS) came out even between the strategies of early ECMO and initial conservative therapy (63.8% vs 71.2%, HR 0.72, 95% CI 0.46-1.12).

There was no benefit in individual components of the primary endpoint except for a lesser need for subsequent MCS in the ECMO group, as nearly 40% of controls relying on inotropes and vasopressors ultimately wound up getting ECMO, according to Petr Ostadal, MD, PhD, of Na Homolce Hospital in Prague, at the American Heart Association (AHA) annual meeting. His group's ECMO-CS report was published simultaneously in Circulation.

"Even in patients with severe or rapidly deteriorating cardiogenic shock, early hemodynamic stabilization using inotropes and vasopressors with implementation of MCS only in case of further hemodynamic worsening is a therapeutic strategy comparable to the immediate insertion of ECMO," Ostadal concluded based on ECMO-CS.

This 117-person trial does not, however, suggest that it's time to retire ECMO for cardiogenic shock, clinicians emphasized.

"The general thought is that ECMO is important for people with cardiogenic shock and is actually very helpful even though this randomized trial did not show that it was effective," said American College of Cardiology vice president B. Hadley Wilson, MD, of Atrium Health's Sanger Heart & Vascular Institute in Charlotte, North Carolina, in an interview.

Larger trials are ongoing, namely the EuroSHOCK and ANCHOR trials both trying to prove a clinical benefit to early ECMO in people with cardiogenic shock following acute coronary syndrome. Researchers are also testing whether ECMO recipients have better outcomes with additional insertion of the Impella device for left ventricular unloading.

The appeal of ECMO is its "capacity to abort multi-organ failure, to stabilize patients going into shock, and further their care and give us time for decision-making in these critically ill patients," said Larry Allen, MD, of UCHealth University of Colorado Hospital in Aurora, speaking at an AHA press conference.

In current practice, clinicians start people in cardiogenic shock with oxygen and ventilatory support, and then consider inotropes and vasopressors or short-term MCS (e.g., ECMO) for further hemodynamic stabilization.

Allen and Wilson both cautioned that although ECMO is becoming easier to deploy in practice, the logistics remain complicated even if future evidence supports this technology for cardiogenic shock.

Wilson told MedPage Today that ECMO is not only costly, but requires manpower for one-on-one and multiple-on-one care. This includes a perfusionist, similar to open-heart surgery, and attendants checking the patient periodically and troubleshooting issues that may occur along the way.

The question is how worthwhile and justifiable this is considering the ongoing healthcare staffing shortages and the potential for clinician burnout, two issues made more acute by the COVID-19 pandemic.

For their trial, Ostadal and colleagues recruited people with severe (SCAI Stage D) or rapidly progressing (SCAI stage D-E) cardiogenic shock at four centers in the Czech Republic.

The 117 participants were enrolled from 2014 to 2022 and randomized to initial ECMO or early conservative therapy, the latter allowing downstream ECMO in case of hemodynamic worsening. Mean age was 66 years, and nearly three-quarters were men in both groups.

At randomization, lactate levels averaged 5 mmol/L and MAP was 64 mmHg. Most individuals were already on mechanical ventilation, norepinephrine, and dobutamine. The cause of cardiogenic shock was ST-segment elevation myocardial infarction in half of cases, and decompensation of congestive heart failure in less than a quarter.

Early ECMO was associated with numerically more bleeding (31.0% vs 20.3%), leg ischemia (13.8% vs 5.1%), and stroke (5.2% vs 0%), none of which reached statistical significance.

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