Ticagrelor and Intracoronary Morphine in Patients Undergoing Primary Percutaneous Coronary Intervention

Overview

A 2 by 2 factorial, multicenter, prospective, randomized, open-label, blinded endpoint trial. Patients undergoing primary PCI for STEMI will be eligible. Enrolled patients will be randomly assigned to the ticagrelor group or the clopidogrel group in a 1:1 ratio. After emergent coronary angiography, patients who have thrombolysis in myocardial infarction (TIMI) flow grade \<2 in coronary angiogram will be randomized again, to either bolus intracoronary injection of morphine sulfate or saline in a 1:1 ratio. Randomization will be stratified by infarct location (anterior vs. non-anterior), and morphine use for pain control before study enroll (for only intracoronary morphine).

1.1. Ticagrelor versus Clopidogrel 1. In spite of timely and successful reperfusion with primary percutaneous coronary intervention (PCI), the mortality rate still remains high1 and substantial numbers of patients suffer from subsequent left ventricular dysfunction or heart failure after ST-segment elevation myocardial infarction (STEMI). 2. One of limitations of primary PCI is distal embolization and effective antiplatelet therapy is needed in patients with STEMI. 3. Clopidogrel is a representative P2Y12 receptor antagonist and has shown consistent efficacy in patients with acute coronary syndromes. However, clopidogrel is a prodrug and has to be converted to an active metabolite to inhibit P2Y12 receptor. Therefore, onset of effect is relatively slow, antiplatelet effect is moderate, and response to clopidogrel shows wide individual variability. 4. Ticagrelor is a new, direct, reversible P2Y12 receptor antagonist, which has rapid and potent antiplatelet effect. In patients who have an acute coronary syndrome with or without ST-segment elevation, treatment with ticagrelor as compared with clopidogrel significantly reduced the rate of death from vascular causes, myocardial infarction, or stroke without an increase in the rate of overall major bleeding. 5. However, there has been no data whether ticagrelor can reduce infarct size compared with clopidogrel in patients undergoing primary PCI. 1.2. Intracoronary morphine administration 1. Lethal reperfusion injury accounts for up to 50% of the final size of a myocardial infarct.5,6 Therefore, adjunctive therapy that is effective in preventing lethal reperfusion injury is needed to potentiate the benefits of primary PCI. 2. During the past few decades, a large number of animal studies demonstrated that commonly used opioids could provide cardioprotection against ischemia-reperfusion injury. Opioid-induced preconditioning or postconditioning mimics ischemic preconditioning or ischemic postconditioning. 3. Recent small clinical trial demonstrated the cardioprotective effect of remote ischemic preconditioning and morphine during primary PCI. But this study was small and did not demonstrate the separate effect of morphine-induced cardioprotection. 2\. Study Objective 1. To investigate the effects of ticagrelor on myocardial infarct size in patients with STEMI undergoing primary PCI compared with clopidogrel 2. To investigate the effects of morphine-induced cardioprotection during primary PCI in patients with STEMI