In study patients, routine primary percutaneous intervention will be commenced. Before reperfusion, saline on room temperature will be infused though the occlusion in the infarct related artery using an over the wire balloon catheter during 10 minutes. The balloon will be inflated to prevent reperfusion in that phase. After 10 minutes the balloon will be deflated allowing reperfusion and infusion with saline on 4°C will be continued for 10 minutes. After this, a coronary stent will be placed. Primary end points are safety and feasibility of this method.