Enoxaparin versus unfractionated heparin in primary percutaneous coronary intervention of ST-elevation acute coronary syndrome: a randomized controlled single center study

INTERVENTION: Group A:bolus injection of UFH 50‐70U/kg before PCI;Group B:bolus injection of Enoxaparin 50U/kg before PCI ; CONDITION: coronary heart disease, ST‐elevation acute coronary syndrome PRIMARY OUTCOME: Liboratory index;Mortality;Days of hospitalization; SECONDARY OUTCOME: Cardiac events;Re‐admission; INCLUSION CRITERIA: 1. ST elevation ACS criteria: (1)ECG changes: New or presumably new ST‐segment elevation >=0.05 MV or new left bundle branch block in at least 2 contiguous leads, or (2) Abnormal cardiac enzymes defined as elevated troponin I, T or creatine phosphokinase‐MB isoenzyme (CPK‐MB) level greater than double value of upper limit of normal; 2. Patients with ST elevation ACS whose symptom onset is within 12 hours of presentation and eligible to have primary PCI; 3. Willing and able to give informed consent.