Reperfusion injury attenuates the beneficial effects of reperfusion therapy for ST-segment elevation myocardial infarction (STEMI). No approach has proven successful in preventing this injury in the clinical setting, thus far. We recently reported a new approach, postconditioning with lactate-enriched blood (PCLeB), for cardioprotection in patients with STEMI. PCLeB comprises intermittent reperfusion and timely coronary injections of lactated Ringer’s solution, aimed at achieving controlled reperfusion with tissue oxygenation and minimal lactate washout. This approach specifically targets reperfusion-induced hypercontracture, which compresses the microvasculature and mechanically disrupts myocardial cell skeletons. Here we report the 1-year outcomes of patients with STEMI treated with PCLeB. Methods and Results: In our modified postconditioning protocol, the duration of each brief reperfusion was prolonged from 10 to 60 s in a stepwise manner. Lactated Ringer’s solution (20-30 mL), containing 28 mM of lactate, was injected directly into the culprit coronary artery at the end of each brief reperfusion, and the balloon was quickly inflated at the site of the lesion to trap the lactate within the ischemic myocardium. Each brief ischemic period lasted 60 s. After 7 cycles of balloon inflation and deflation, full reperfusion was performed; subsequently, stenting was performed and the percutaneous coronary intervention (PCI) was completed. Between March 2014 and June 2017, we have treated 62 consecutive patients with STEMI (age, 64.9 ± 13.7 years; 75.8% men) using PCI and PCLeB within 12 h of symptom onset in our hospital. None of the patients experienced ventricular tachycardia/fibrillation that required pharmacological intervention or electrocardioversion during reperfusion. None of the patients experienced angiographic no-reflow or required intra-aortic balloon counterpulsation for poor coronary flow recovery. The mean peak CK and CK-MB levels were 2784 ± 2184 and 269 ± 177 IU/L, respectively. The mean corrected TIMI frame count after PCI was 20.4 ± 10.4 (normal value, 21). At 1-year follow-up, none of the patients had died or experienced re-hospitalization for heart failure. Conclusions: PCLeB induced good microcirculation recovery, abolished reperfusion arrhythmia, and yielded zero mortality and no re-hospitalization for heart failure at 1-year follow-up in 62 consecutive patients with STEMI.