P3AMI Antiplatelet Trial

Major heart attacks are caused by a numerous factors, including sudden clot formation in a coronary artery leading to a blockage and heart muscle death. The clots are largely made of sticky clotting blood cells (platelets). A patient having a major heart attack is treated with emergency primary percutaneous coronary intervention (PPCI) where a wire and balloon are used to reopen the coronary artery and a stent (a slotted metal tube) is placed to keep the artery open. Aspirin, and one of two other antiplatelet drugs (prasugrel or ticagrelor) are given prior to PPCI to prevent further clots formation. Both antiplatelet drugs are taken in tablet form and in healthy stable patients these drugs take at least 30 min to 2 hours to exert an adequate effect. Often PPCI procedures are performed well within this timescale. It is possible that having a major heart attack limits the bodies ability to absorb the drugs also. In this study, patients with major or minor heart attacks will be given either prasugrel or ticagrelor as per licensed indications and guideline recommendations. A 15 ml blood sample will be taken at first balloon inflation to reopen the blocked artery, then after 20 minutes, 60 minutes, and 4 hours after taking the drugs. Each blood sample will be subjected to a variety of tests to determine antiplatelet drug activity. This study will identify which of the two agents used are working effectively during PPCI, given the very short timescales involved. It will also show if patients with major heart attacks absorb the drugs less well than patients with less severe heart attacks. In the future it might be that an intravenous agent will be more valuable in the setting of PPCI.