CARdiAc Mri and BiOLogical samplEs at the Acute Phase of a Myocardial Infarction (CARAMBOLE)

Myocardial infarction is one of the leading causes of morbi-mortality, causing 75% of cases of sudden death in adults over 35 years of age and more than half of chronic heart failure. Despite the progress made, based on French data from the CIRCUS study and the FAST-MI registry, all-cause mortality at 1 year remained high at around 8% and the rate of occurrence of composite events (death, heart failure, myocardial infarction, revascularization, stroke) estimated around 25%. ST-segment elevation myocardial infarction (STEMI) is the most severe form of ischemic myocardial disease. The recommended treatment is the quickest possible unblocking of the coronary artery responsible for STEMI, by coronary angioplasty (treatment of choice if time limits are compatible) or, more rarely, thrombolysis. However, this revascularization causes undesirable collateral effects with tissue edema, intra-myocardial hemorrhages, microvascular obstruction and local inflammation which contribute to significantly aggravate myocardial damage. These "reperfusion injuries" increase the risk of Left Ventricular (LV) dysfunction. Thus, immediate mortality decreases but the incidence of heart failure following STEMI increases. Several other parameters associated with a poor prognosis remain to this day incompletely understood and treated: deleterious left ventricular remodeling (LVR), post-infarction inflammation, no-reflow.

Furthermore, performing a systematic MRI at the acute phase of STEMI will allow to assess the real prevalence of intra LV thrombi and to treat them before hospital discharge. Indeed, the prevalence of intraLV thrombi is estimated around 20% but only 16% are diagnosed during the stay in the Cardiology Intensive Care Unit (CICU) (low sensitivity of echocardiography, lack of availability of cardiac MRI) . These patients must be treated with anticoagulants to limit the embolic phenomena of intra LV thrombi, in particular strokes, but most patients therefore do not benefit from this treatment when leaving the hospital since MRI is not performed in the acute phase in most centers due to lack of availability.

The organization of prospective cohorts with well-documented biological and imaging collections, in particular the systematic use of myocardial MRI, and monitoring of events at 1 year, will thus make it possible to better understand the complex pathophysiology of these deleterious phenomena, their clinical consequences, to propose research hypotheses and ultimately, to developp innovative and personalized treatments.

Inclusion criteria

• Patient ≥18 years old, hospitalised in cardiology departments at the C.H.U. of Poitiers
• Myocardial infarction type 1, 2 or 3 according to the 4th universal definition, with elevation of ST segment ≥0.2 milliVolt in two contiguous derivations of the ECG.
• Patient able to comply with study procedures
• Patient legally free and not subject to any custody, guardianship, tutelage or subordination measures
• Informed consent signed by the patient/relative or trusted person after clear and complete information about the clinical investigation.

Exclusion criteria

• Subject with contraindication to MRI : pregnancy, ocular metallic foreign body (accidental or other chips), pace-maker incompatible with MRI, foreign ferromagnetic ocular or cerebral bodies, cochlear implants and in general all electronic medical material immovably implanted and incompatible with MRI; metallic heart valve of 1st generation, vascular clips formerly implanted on cranial aneurysm, severe renal insufficiency
• Patient suffering from claustrophobia
• Hypersensitivity to gadoteric acid, to meglumine or to a drug containing gadolinium
• patients with insufficient venous access for contrast medium injection.
• Participation in another interventional study with an investigational drug or device, which, in the judgment of the investigator, could interfere with the present study
• Patients not benefiting from a Social Security scheme or not benefiting from it through a third party
• Persons benefitting from enhanced protection, namely minors, pregnant women, persons deprived of their liberty by a judicial or administrative decision, patients staying in a health or social establishment, adults under legal protection