 Diagnosis and Main Criteria for Selection: Adult subjects 18 years with an onset of symptoms of 20 minutes min and 12 h will be enrolled based on a diagnosis of STEMI with ST segment elevation of 1 mm in 2 contiguous precordial leads, or presumably new left bundle branch block and who have Thrombolysis in Myocardial Infarction TIMI 0 or 1 flow in the infarct related artery IRA and fulfill angiographic criteriascore for a large infarction and are candidates for PPCI. All subjects should receive as soon as logistically feasible: aspirin 150-325 milligrams mg orally, or 250 500 mg intravenously IV and a loading dose of any approved P2Y12 inhibitor unless already on maintenance dose. 