Coronary Microcirculation Assessment After Primary Angioplasty in Myocardial Infarction

All patients presenting for STEMI by occlusion of a proximal coronary artery, vascularizing a large volume of myocardium corresponding to an APPROACH score\> 21, in the first 12 hours following the onset of chest pain, will be included. Data relating to medical history, lifestyle (sedentary lifestyle, smoking, drug use), cardiovascular risk factors will be collected. The management of acute coronary syndrome will be carried out in accordance with the European Society of Cardiology guidelines of 2015. An emergency coronary angiography will be used to revascularise the patient as indicated. Thromboaspiration, stenting, antithrombotic agents and other treatments will be administered according to angiographic and clinical criteria. The FFR guide (PressureWire® Certus® from St Jude Medical Abbott) will be used to make pressure and temperature measurements. It has been used in daily practice since the FAME study in 2011 to guide the therapeutic decision in patients with an intermediate lesion. An injected cardiac magnetic resonance imaging (MRI) will be performed between 48 hours and 7 days following the infarction in accordance with current practices.The initial trans-thoracic ultrasonography as well as the various blood samplings will be performed according to standard practice. The Rayflow® microcatheter will be used to allow the optimal delivery of physiological saline solution into the studied artery. It will be mounted on the FFR guide already in place as part of the angioplasty procedure. Bayer's Medrad® Mark 7 Arterion® infuser will be used to deliver saline continuously at a flow rate of 15-20 mL/min through the Rayflow® microcatheter