Early Initiation of Low Dose Tirofiban for PPCI in STEMI Patients.

Early Initiation of Low Dose Tirofiban for Primary Percutaneous Coronary Intervention in Patients With ST-segment Elevation Myocardial Infarction.

Anti-platelet therapy is a key point of acute myocardial infarction (AMI) treatment. Nowadays, dual anti-platelet therapy based on aspirin and ADP-P2Y12 receptor inhibitor is the preferred treatment before primary percutaneous coronary intervention (PPCI). Restricted by pharmacokinetic and pharmacodynamic characteristics, ADP-P2Y12 receptor inhibitors cannot take effect immediately after oral administration. However, platelet glycoprotein Ⅱb / Ⅲa inhibitors take effect faster. Previous clinical trials indicated that combination of full dose of glycoprotein Ⅱb / Ⅲa inhibitor and dual anti-platelet therapy reduced AMI related ischemia events but increased bleeding events significantly. The high dose of glycoprotein Ⅱb / Ⅲa inhibitor may be the key factor contributing to the increased bleeding events. Therefore, this study aims to evaluate the effectiveness and security of triple anti-platelet therapy based on a small dose of glycoprotein Ⅱb / Ⅲa inhibitor, aspirin and ADP-P2Y12 receptor inhibitor in AMI patients receiving PPCI.

Upon being diagnosed as ST Elevation Myocardial Infarction, if informed consent is obtained, patients start to receive Tirofiban(0.05mg/ml) intravenous drip in a dosage of 4ml/hour (patients weight<50kg) or 6ml/hour (patients weight > 50kg) lasting for 24 hours.

Upon being diagnosed as ST Elevation Myocardial Infarction, if informed consent is obtained, patients start to receive normal saline intravenous drip in a dosage of 4ml/hour (patients weight<50kg) or 6ml/hour (patients weight > 50kg) lasting for 24 hours.

TFG(TIMI flow grades) grade III: complete myocardial perfusion immediately after primary percutaneous coronary intervention detected by DSA(Digital Substraction Angiography).

TMP(TIMI myocardial perfusion grades) grade III: complete myocardial perfusion immediately after primary percutaneous coronary intervention detected by DSA(Digital Substraction Angiography).

Major adverse cardiovascular events(MACE), including a composite of all-cause death, nonfatal myocardial infarction, stroke, target vessel revascularization.

Major adverse cardiovascular events, including a composite of all-cause death, nonfatal myocardial infarction, stroke, target vessel revascularization.

All the bleeding events assessed by bleeding academic research consortium(BARC) definition for bleeding)

All the bleeding events assessed by bleeding academic research consortium(BARC) definition for bleeding)

Any intracranial bleeding (excluding microhemorrhages <10 mm evident only on gradient-echo MRI); Clinically overt signs of hemorrhage associated with a drop in hemoglobin of ≥ 5 g/dL; Fatal bleeding (bleeding that directly results in death within 7 d).

GUSTO bleeding criteria:Severe or life-threatening : Intracerebral hemorrhage ; Resulting in substantial hemodynamic compromise requiring treatment. Moderate: Requiring blood transfusion but not resulting in hemodynamic compromise. Mild : Bleeding that does not meet above criteria.

Major bleeding events assessed by international society on thrombosis and haemostasis(ISTH) bleeding criteria.

Fatal bleeding and/or symptomatic bleeding in a critical area or organ such as intracranial, intraspinal, intraocular, retroperitoneal, intra-articular or pericardial, or intramuscular with compartment syndrome, and/or bleeding causing hemoglobin drop of 20 g/L or more, and/or blood transfusion of 2 units or more

Inclusion Criteria: Time after onset of chest pain: ≥ 30 minutes and ≤ 24 hours; ST segment elevated ≥ 0.1mV in adjacent two or more leads; Scheduled for primary percutaneous coronary intervention without contraindications; Written informed consent is obtained. Exclusion Criteria: Life expectancy ≤ 1 year; History of cerebral hemorrhage; History of stroke in 6 months; Active hemorrhage; Severe hepatic and renal dysfunction(ALT > 3 folds of upper limit of normal, eGFR < 30ml/min/1.73mm^2 or Scr > 200 mmol/L); Known hemorrhagic diseases; Known malignant tumour diseases； Active peptic ulcer disease; Blood platelet counts < 100×10^9/L; Blood hemoglobin < 90g/L; Pregnancy or lactation period； Take part in other intervention clinical trials； Investigators think not suitable to participate in this trial.