Avoid Routine Early ECMO in Severe Cardiogenic Shock: ECMO-CS

November 06, 2022

Routine early, expeditious use of extracorporeal membrane oxygenation (ECMO) is a common strategy in patients with severe cardiogenic shock, but a less aggressive initial approach may be just as effective, a randomized trial suggests.

In the study that assigned patients with "rapidly deteriorating or severe" cardiogenic shock to one or the other approach, clinical outcomes were no better for those who received immediate ECMO than for those initially managed with inotropes and vasopressors, researchers said.

The conservative strategy, importantly, allowed for downstream ECMO in the event of hemodynamic deterioration, which occurred in a substantial 39% of cases, observed Petr Ostadal, MD, PhD, when presenting the results November 6 at the American Heart Association (AHA) Scientific Sessions 2022, held in Chicago and virtually.

Ostadal, of Na Homolce Hospital, Prague, Czech Republic, is also first author on the published report of the study, called Extracorporeal Membrane Oxygenation in the Therapy of Cardiogenic Shock (ECMO-CS), which was published the same day in Circulation.

The trial makes a firm case for preferring the conservative initial approach over routine early ECMO in the kind of patients it entered, Larry A. Allen, MD, MHS, University of Colorado School of Medicine, Aurora, told theheart.org | Medscape Cardiology.

More than 60% of the trial's 117 patients had shock secondary to an acute coronary syndrome; another 23% were in heart failure decompensation.

A preference for the conservative initial approach would be welcome, he said. The early aggressive ECMO approach is resource-intensive and carries some important risks, such as stroke or coagulopathy, said Allen, who is not connected with ECMO-CS. Yet it is increasingly the go-to approach in such patients, based primarily on observational data.

Although early ECMO apparently didn't benefit patients in this study in their specific stage of cardiogenic shock, Allen observed, it would presumably help some, but identifying them in practice presents challenges. "Defining where people are in the spectrum of early versus middle versus late cardiogenic shock is actually very tricky."

It will therefore be important, he said, to identify ways to predict which conservatively managed patients do well with the strategy, and which are most at risk for hemodynamic deterioration and for whom ECMO should be readily available.

"I think part of what ECMO-CS tells us is that, if a patient is stable on intravenous inotropic and vasopressor support, you can defer ECMO while you're thinking about the patient — about their larger context and the right medical decision-making for them."

The trial randomly assigned 122 patients with rapidly deteriorating or severe cardiogenic shock to the immediate ECMO or the conservative strategy at four centers in the Czech Republic. The 117 patients for whom informed consent could be obtained were included in the analysis, 58 and 59 patients, respectively. Their mean age was about 65 years and three-fourths were male.

The primary endpoint, the only endpoint for which the study was powered, consisted of death from any cause, resuscitated circulatory arrest, or use of a different form of mechanical circulatory support (MCS) by 30 days.

It occurred in 63.8% of patients assigned to immediate ECMO and 71.2% of those in the conservative strategy group, for a hazard ratio (HR) of 0.72 (95% CI, 0.46 - 1.12; P = .21).

As individual endpoints, rates of death from any cause and resuscitated arrest did not significantly differ between the groups, but conservatively managed patients more often used another form of MCS. The HRs were:

  • 1.11 (95% CI, 0.66 - 1.87) for death from any cause

  • 0.79 (95% CI, 0.27 - 2.28) for resuscitated cardiac arrest      

  • 0.38 (95% CI, 0.18 - 0.79) for use of another MCS device

The rates for serious adverse events — including bleeding, ischemia, stroke, pneumonia, or sepsis — were similar at 60.3% in the early-ECMO group and 61% in group with conservative initial management, Ostadal reported.

Other than the 23 patients in the conservative initial strategy group who went on to receive ECMO (1.9 days after randomization, on average), 1 went on to undergo implantation with a HeartMate (Abbott, Abbott Park, Illinois) ventricular assist device and 3 received an Impella pump (Abiomed, Danvers, Massachusetts).

Six patients in the early-ECMO group were already receiving intra-aortic balloon pump (IABP) support at randomization, 2 underwent temporary implantation of with a Centrimag device (Abbott), and 3 went on to receive a HeartMate device, the published report notes.

ECMO is the optimal first choice for MCS in such patients with cardiogenic shock who need a circulatory support device, especially because it also oxygenates the blood, Ostadal told theheart.org | Medscape Cardiology.

But ECMO doesn't help with ventricular unloading. Indeed, it can sometimes reduce ventricular preload, especially if right-heart pressures are low. So MCS devices that unload the ventricle, typically an IABP, can complement ECMO.

Ostadal speculates, however, that there may be a better pairing option. "Impella plus ECMO, I think, is the combination which has a future," he said, for patients in cardiogenic shock who need a short-term percutaneous hemodynamic support device. Impella "supports the whole circulation" and unloads the left ventricle.

"A balloon pump in combination with ECMO is still not a bad choice. It's very cheap in comparison with Impella." But in his opinion, Ostadal said, "The combination of Impella plus ECMO is more efficient from a hemodynamic point of view."

As the published report notes, ongoing randomized trials looking at ECMO plus other MCS devices in cardiogenic shock include ECLS-SHOCK, with a projected enrollment of 420 patients, and EURO-SHOCK, aiming for a similar number of patients; both compare routine ECMO to conservative management.

In addition, ANCHOR, in which ECMO is combined with IABP, and DanShock, which looks at early use of Impella rather than ECMO, are enrolling patients with shock secondary to acute coronary syndromes.

Ostadal discloses consulting for Getinge, Edwards, Medtronic, Biomedica, and Xenios/Fresenius and receiving research support from Xenios/Fresenius. Allen discloses modest or significant relationships with ACI Clinical, Novartis, UpToDate, Boston Scientific, and Cytokinetics.

American Heart Association (AHA) Scientific Sessions 2022. LBS.03. Presented November 6, 2022.

Circulation. Published online November 6, 2022.  Abstract

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