Lactated Ringer's solution for preventing myocardial reperfusion injury

Reperfusion of ischemic myocardium is crucial for salvaging myocardial cells from ischemic cell death. However, reperfusion itself induces various deleterious effects on the ischemic myocardium. These effects, known collectively as reperfusion injury, comprise stunned myocardium, reperfusion-induced arrhythmia, microvascular reperfusion injury, and lethal reperfusion injury. No approach has proven successful in preventing any of these injuries in the clinical setting. My colleagues and I recently proposed a new postconditioning protocol, postconditioning with lactate-enriched blood (PCLeB), for the prevention of reperfusion injury. This new approach consists of intermittent reperfusion and timely coronary injections of lactated Ringer's solution, aiming to achieve controlled reperfusion with cellular oxygenation and minimal lactate washout from the cells. This approach appeared to be effective in preventing all types of reperfusion injury in patients with ST-segment elevation myocardial infarction (STEMI), and we have already reported excellent in-hospital outcomes of patients with STEMI treated using PCLeB. In this review article, I discuss a possible mechanism of reperfusion injury, which we believe to be valid and which we targeted using this new approach, and I report how the approach worked in preventing each type of reperfusion injury.