Outcome of patients admitted with oxygen mismatch and myocardial injury or infarction in emergency departments

Aims To describe the outcomes and associated factors in a population of patients admitted to emergency departments with at least one condition of oxygen supply/demand imbalance, regardless of the troponin result or restrictive criteria for type 2 myocardial infarction. Methods We constituted a retrospective cohort of 824 patients. Medical records of patients having undergone a troponin assay were reviewed for selection and classification, and data including in-hospital stay and readmissions were collected. The reported outcomes are in-hospital mortality, 3-year mortality, and major adverse cardiovascular events. Results Patients with myocardial infarction or injury, either chronic or acute, were older, with more history of hypertension and chronic heart or renal failure but not for other cardiovascular risk factors and medical history. Acute myocardial injury and type 2 myocardial infarction were significantly associated with in-hospital mortality [odds ratio (OR) 3.71 95% confidence interval (CI) 1.90–7.33 and OR 3.15 95% CI 1.59–6.28, respectively]. However, the long-term mortality does not differ in comparison with patients presenting chronic myocardial injury or nonelevated troponin, ranging from 26.9 to 34.3%. Patients with chronic myocardial injury and type 2 myocardial infarction had more long-term major cardiovascular events (39.3 and 38.8%), but only for acute heart failure, and none was associated with this outcome after adjustment. Conclusion Among patients admitted to emergency departments with an oxygen supply/demand imbalance, acute myocardial injury and type 2 myocardial infarction are strongly associated with in-hospital mortality. However, they are not associated with higher long-term mortality or major cardiovascular events after discharge, which tend to occur in elderly people with comorbidities.