Study population The study will include 600 patients with acute myocardial infarction with ST elevation (STEMI) who are eligible for treatment with primary percutaneous coronary intervention (PPCI) within 12 hours from the onset of symptoms. Enrollment started on January 2017 . Recruitment will continue until 600 patients have been randomized. The end of the recruitment period is planned for January 2020. The trial will continue until all available survivors have been followed for at least 4 years.