Super Saturated Oxygen (SSO2) Therapy in Patients With ST-segment Elevation Myocardial Infarction (STEMI) and Action on Coronary Microcirculation Dysfunction

Ten patients with acute anterior STEMI undergoing primary PCI will be enrolled. After successful PCI of a proximal lesion or middle left anterior descending artery (LAD), the patient will be informed and emergency consent will be obtained.

SSO2 therapy will then be performed. Blood is drawn from a femoral artery sheath and circulated via a roller pump through an extracorporeal oxygenator located in a polycarbonate chamber to achieve a PaO2 of 760 to 1000 mmHg. The overoxygenated blood is then delivered to the origin of the LAD at a flow rate of 100 ml/min for 60 minutes via a dedicated catheter.

Improvement in CMD will be assessed by comparing angio-IMR before and after 60 minutes of SSO2 therapy measured on conventional angiographic images. Then, conventional follow-up of previous STEMI will be performed by imaging and functional assessment.

The primary endpoint will be analyzed using a paired Student's t test, to take into account the evolution "before/after" implementation of SSO2 therapy on CMD.

The demonstration of the beneficial effect of SSO2 therapy on CMD will allow the development of a care strategy based on CMD measurement by angio-IMR. Thus, this new treatment could be reserved for patients with severe CMD for which our management arsenal is still lacking, even though we know that CMD is a major prognostic factor in STEMI patients.

Inclusion criteria

• Age >18 years and <80 years
• ST-segment elevation myocardial infarction within 6 hours of symptom onset with ≥1 mm ST-segment elevation in ≥2 contiguous leads in V1-V4 or new left bundle branch block.
• Successful PCI of a proximal or medial LAD lesion with commercially available coronary stents and achievement of residual stenosis <50% diameter and thrombolysis-in-myocardial-infarction (TIMI) flow grade 2 or 3.
• Systemic arterial pO2 greater than or equal to 10.7 kPa or 80 mmHg with or without oxygen supplementation.
• Patient enrolled in a social security plan or beneficiary of such a plan
• Consent obtained from the patient before inclusion (Emergency consent)

Exclusion criteria

• History of anterior coronary artery bypass grafting (CABG)
• Previous myocardial infarction
• History of PCI on the LAD
• New LAD PCI planned within 30 days.
• Mechanical complications of STEMI (Patients with ventricular pseudoaneurysm, ventricular septal defect (VSD), or severe mitral valve regurgitation (with or without papillary muscle rupture)), cardiogenic shock, or Presence of an intra-aortic counterpulsation balloon.
• Valvular stenosis or heart failure, pericardial disease, or nonischemic cardiomyopathy.
• Known prior left ventricular ejection fraction (LVEF) < 40%,
• Use of thrombolytic therapy
• Patients with a contraindication to anticoagulant therapy.
• Creatinine clearance <30 ml/min/1.73 m2,
• Hemoglobin <10 g/dL
• Gastrointestinal or urogenital bleeding within the last two months or any major surgery (including CABG) within six weeks prior to surgery.
• Female of childbearing age
• Patient on deferral or participating in another clinical investigation,
• Protected populations: pregnant women, parturients, nursing mothers; persons deprived of liberty by a judicial or administrative decision; protected adults