A system and methods are described for improving the management of ischemic cardiac tissue during acute coronary syndromes. The system combines a catheter-based sub-system which allows for simultaneous balloon dilation of a coronary artery and infusion of a carefully controlled perfusate during percutaneous coronary intervention. The system allows for modulation of levels of oxygen at the time of percutaneous intervention. In addition, catheters and systems are provided for administration of fluids with modified oxygen content during an intervention that incorporate upstream flow control members to compartmentalize the perfusion of the target coronary artery and the remainder of the heart.