Impact of clinical diagnosis of myocardial infarction in patients with elevated cardiac troponin

OBJECTIVE: Type 2 myocardial infarction (MI) and myocardial injury are common conditions associated with an adverse prognosis. Physicians experience uncertainty how to distinguish these conditions, as well as how to manage and treat them. Therefore, the objective of this study was to compare treatment and prognosis in patients with an adjudicated diagnosis of type 2 MI and myocardial injury, who were discharged with and without a clinical diagnosis of MI. DESIGN: The study consisted of two cohorts, 964 and 281 consecutive patients with elevated cardiac troponin, discharged with and without a clinical diagnosis of MI, respectively. All cases were adjudicated into MI type 1-5 or myocardial injury and followed regarding all-cause death. RESULTS: The adjudication identified 138 and 37 cases of type 2 MI, and 86 and 185 of myocardial injury, with and without a clinical MI diagnosis, respectively. In patients with type 2 MI, a clinical MI diagnosis was associated with more coronary angiography investigations (39.1% vs 5.4%, p<0.001) and an increased use of secondary prevention medications (all p<0.001). However, no difference was observed in adjusted 5-year mortality between patients with and without a clinical MI diagnosis (HR: 0.77 with 95% CI 0.43 to 1.38). The results were similar for adjudicated myocardial injury. CONCLUSION: In both type 2 MI and myocardial injury, a clinical diagnosis of MI at discharge was associated with more investigations and treatments. However, no prognostic effect of receiving a clinical MI diagnosis was observed.