In this issue of Circulation: Cardiovascular Interventions , Maioli and colleagues, from Florence, Italy, report the results of a 450-patient, prospective, randomized trial of patients with ST-elevation–myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI).1 Patients with STEMI are at high risk of the development of contrast-induced acute kidney injury (CI-AKI). Accordingly, the authors randomly assigned patients into 1 of 3 groups: early hydration with a bolus of sodium bicarbonate started in the emergency room followed by a 12-hour infusion; postprocedural hydration with a normal saline drip started after PCI; and last, no specific hydration protocol. Patients enrolled were fairly typical of those presenting with STEMI, with a mean age in the mid-60s; almost a quarter were over 75 years of age, and the majority were male. Slightly more than 22% were diabetic, about 40% presented with anterior myocardial infarction, and almost 40% had an ejection fraction of <0.40. The incidence of shock was 5%, but intra-aortic balloon pumps were used liberally in almost 20% of cases. More than a quarter of patients had an estimated glomerular filtration rate (eGFR) of ≤60 mL/min. Although the mean door-to-balloon time of 85 minutes could be criticized, such values were not unusual in the mid-2000s, when the study was performed. Overall, clinical outcomes were acceptable, with 16 deaths, 6 strokes, and a cumulative number of adverse cardiac events of 45 (10%). The main finding of the trial was a significantly lower incidence of CI-AKI, no matter which definition was used, among patients randomly assigned to the early hydration group. Article see p 456 A number of points regarding this important trial bear emphasis. First, patients with STEMI are at particularly high risk of CI-AKI, as evidenced by the 27% incidence of CI-AKI observed in the control group of this trial. Operators are …