Montoy JCC, Shen YC, Brindis RG, et al. - In patients diagnosed with non–ST‐segment–elevation myocardial infarctions (NSTEMIs), the impacts of ST‐segment–elevation myocardial infarction regionalization schemes on treatment and outcomes were evaluated. A difference‐in‐differences approach was applied to examine the data of 293,589 patients with NSTEMIs who received care in regionalized and nonregionalized communities in California from January 1, 2005 to September 30, 2015 in this cohort study. For patients with NSTEMI, ST‐segment–elevation myocardial infarction regionalization programs were not statistically correlated with modifications in guideline‐recommended early angiography or changes in mortality risk. The data exhibited that secular trends unrelated to regionalization policies accounted for the increases in the proportion of patients with NSTEMI who had undergone guideline‐directed angiography and reductions in the risk of mortality.