Assessment of ECMO in Acute Myocardial Infarction Cardiogenic Shock

Scientific background

• Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is used more and more frequently in patients with acute myocardial infarction (AMI) and refractory cardiogenic shock despite the absence of high level scientific evidence to recommend the use of temporary circulatory support devices (TCS) in this setting.TCS support may also benefit to cardiogenic shock patients not initially refractory to conventional medical management since their mortality exceeds 40% and most of deaths are due to the development of refractory cardiogenic shock and multiple organ failure.

The ANCHOR trial is therefore designed to test the hypothesis that VA-ECMO support associated with IABP results in improved outcomes in comparison with optimal medical treatment alone in patients with AMI and cardiogenic shock. An ethical rescue option to VA-ECMO will however be provided to control patients with cardiogenic shock refractory to conventional medical treatment since recent data suggested survival up-to 50% with ECMO support in this setting.

Main objective - To determine if early VA-ECMO combined with IABP support and optimal medical treatment would improve the outcomes of patients with acute myocardial infarction complicated by cardiogenic shock as compared with optimal medical treatment alone.

Scope of the study

• Patients satisfying all of the Inclusion and Exclusion Criteria will be classified as 'Eligible'. Consent to research will be obtained from a close relative or surrogate for all eligible patients prior to randomization.

Should such a person be absent, eligible patients will be randomized according to the specifications of emergency consent and the patient will be asked to give his/her consent for the continuation of the trial when his/her condition will allow.

Randomization will be possible in centers with robust experience in the management of AMI and cardiogenic shock but no on-site ECMO capability providing that an ECMO retrieval team from the nearest ECMO center can establish ECMO no later than 2 hours after randomization.

Before randomization, physicians at the non-ECMO center will check that the ECMO team is immediately available and that an ICU/CCU bed is available at the ECMO center. Thereafter, if the patient is randomized to the ECMO arm, the mobile ECMO retrieval team will travel to the center, initiate VA-ECMO and will rapidly transfer the patient on VA-ECMO to the ECMO center.

Description of experimental ECMO + IABP Arm

• Protocolized conventional management of cardiogenic shock
• VA-ECMO will be started as soon as possible
• For patients randomized at non-ECMO centers, a mobile ECMO team will initiate ECMO at the non-ECMO center and transport the patient to the ECMO center immediately
• IABP inserted in the contralateral femoral artery (unless technically not possible)
• ECMO management according to protocol
• ECMO weaning according to protocol

Description of conventional treatment Arm

• Protocolized conventional management of cardiogenic shock
• IABP not recommended. No other TCS device (e.g., ECMO, Impella, Thoratec PHP, TandemHeart) permitted
• Rescue VA-ECMO only if one of 1 or 2 or 3 applies:
• 1. Refractory cardiogenic shock defined as

• Cardiac index <1.2 l/min/m² or VTI <6 cm AND
• Assessment and correction of hypovolemia AND
• (dobutamine ≥15 microg/kg/min + norepinephrine ≥1.5 microg/kg/min) OR epinephrine ≥ 0.75 microg/kg/min
• Serum lactate >5 mmol/L or serum lactate increased >50% in the last 6 hours
• 2. Uncontrolled lethal arrhythmia despite K >4.5 mmol/l AND Mg >1.0 mmol/l AND Intubation and mechanical ventilation with deep sedation AND IV Loading of amiodarone AND IV xylocaine
• 3. Refractory cardiac arrest

Mandatory validation of rescue VA-ECMO by an independent adjudicator.

Inclusion criteria

• Cardiogenic shock complicating acute myocardial infarction (STEMI or NSTEMI)
• Revascularization by PCI for acute myocardial infarction has been performed or is planned in the following 60 minutes
• Systolic blood pressure <90 mmHg for >30 min or catecholamine support required to maintain systolic blood pressure >90 mmHg
• Signs of pulmonary congestion
• Signs of impaired organ perfusion with at least one of the following:

Altered mental status OR cold, clammy skin and extremities OR oliguria with urine output <30 ml/h OR serum lactate >2.0 mmol/l

Exclusion criteria

• Age <18 years
• Pregnancy
• Onset of shock >24 Hours
• Shock of other cause (hypovolemic, anaphylactic or vagal shock)
• Shock due to massive pulmonary embolism
• Resuscitation >30 minutes
• No intrinsic heart activity
• Patient moribund on the day of randomization or SAPS II >90
• Surgical revascularization for AMI (CABG) planned or already performed prior to randomization
• Cerebral deficit with fixed dilated pupils or Irreversible neurological pathology
• Mechanical infarction complication (massive mitral regurgitation, pericardium drainage required, septal ventricular defect)
• Severe peripheral artery disease or previous aortic or ilio-femoral surgery precluding ECMO and IABP insertion
• Aortic regurgitation > II
• Other severe concomitant disease with limited life expectancy < 1 year
• Proven heparin-induced thrombocytopenia
• ECMO device not immediately available