REMAP ECMO is a registry based platform in which multiple response adaptive randomized clinical trials (trial domains) will be embedded. These trial domains will, in a perpetual way, study the effects of a range of patient management strategies which aim to improve VA ECMO weaning success. A first trial domain will address the effects of left ventricular (LV) unloading through intra-aortic balloon pumping on weaning succes in VA ECMO supported patients.

ExtraCorporeal Membrane Oxygenation (ECMO) is increasingly used but remains associated with high weaning failure- and mortality- rates. This seems in part attributable to a knowledge gap on how to properly manage ECMO and its related therapies as current knowledge and treatment protocols are based on observational studies and expert opinions. The "Randomized Embedded Multifactorial Adaptive Platform in ECMO" (REMAP ECMO) study was developed to study, in an efficient and randomized way, different ECMO related patient management issues and will consist of two parts:

1. A patient registry that will serve for quality monitoring and observational studies of ECMO patients being treated in participating centers.

2. Embedded within the registry, multiple response adaptive randomized clinical trials (trial domains) which aim to evaluate the effectiveness of a range of therapeutic interventions on ECMO weaning success. These interventions all have in common that they are all already used in ECMO care but their use depends on center and/or doctors preferences as no high quality (randomized) evidence guiding their indication, timing and management exists.

   • LV unloading trial A first trial domain to be initiated within the REMAP ECMO platform will address the effects of left ventricular (LV) unloading, through application of an intra-aortic balloon pump (IABP), on weaning success in the setting of venoarterial (VA) ECMO. The rationale of this trial domain is based on the increase in LV loading conditions, as induced by VA ECMO, which could lead to pulmonary edema, intracardiac thrombosis and even death. These serious sequelae could possibly be prevented by adding IABP as adjunct to VA ECMO therapy.
   • Physiological substudy on IABP as adjunct to V-A ECMO

A nested physiological observational substudy within the ongoing REMAP ECMO RCT, using the trial arms where patients are randomized between receiving V-A ECMO with or without IABP in the Erasmus Medical Center Rotterdam. The substudy aims to evaluate the physiological effects of IABP in conjunction with V-A ECMO on respiratory and hemodynamic parameters. The substudy consists of two parts:

1. Microcirculation and Macrocirculation: This part investigates the impact of IABP on both microcirculation and macrocirculation in the setting of V-A ECMO.
2. PEEP as an Unloading Modality: This part examines the effect of Positive End-Expiratory Pressure (PEEP) as an unloading modality during a decremental PEEP trial in patients receiving V-A ECMO, either with or without IABP.

Endpoints in both substudies that can be assessed blindly will be evaluated by an assessor who is blinded to the assigned treatment arm and the objectives of the substudy

Inclusion criteria for the registry backbone:

• Having received ECMO support for severe circulatory and/or respiratory insufficiency

Inclusion Criteria for the LV unloading trial domain (VA ECMO + IABP vs VA ECMO alone):

• Cardiogenic shock
• Having received VA ECMO support for severe circulatory (and respiratory insufficiency).
• Age ≥ 18 years
• Initiation of LV unloading (IABP or Impella) possible ≤ 8 hours after ECMO initiation

Exclusion criteria for the registry backbone

• Objection to participation in the registry by the patient and/or proxy
• VA ECMO usage confined to the period during surgery or another intervention (the VA ECMO was removed at the end of the intervention in the operation room).

Exclusion criteria for the LV unloading trial domain (VA ECMO + IABP vs VA ECMO alone)

• No (deferred) informed consent provided by the patient and/or proxy.
• Pregnancy
• ECMO usage confined to the period during surgery or another intervention (the ECMO was removed at the end of the intervention).
• Isolated right ventricular failure (e.g. due to pulmonary embolism).
• Left ventricular assist device (LVAD), Impella or IABP in situ.
• Ventricular septal defect or papillary muscle rupture as the cause of shock.
• Thoracic or abdominal aortic dissection.
• Moderate or severe aortic regurgitation
• Mechanical prosthesis in mitral valve position

No masking is possible as the device is visible after placement.