Differential diagnostic factors of type 1 and type 2 myocardial infarction in patients with elevated cardiac troponin levels

OBJECTIVE: Emergency physicians experience difficulty in determining the disposition of patients with elevated troponin I levels using emergency room tests. In this study, we aimed to investigate factors that could discriminate between the occurrence of type 1 myocardial infarction (T1MI) and type 2 myocardial infarction (T2MI) in patients with elevated troponin I levels. METHODS: Patients admitted to the emergency department between January 1, 2017 and June 30, 2017 with elevated troponin I levels who underwent subsequent cardiac biomarker testing were included. Samples for baseline blood tests, such as cardiac biomarker levels, were collected within approximately 10 minutes of admission. Electrocardiogram, transthoracic echocardiography, and percutaneous coronary intervention results were retrospectively examined via patient report and chart reviews. RESULTS: During the study period, 169 of 234 (72%) patients were diagnosed with T2MI and 65 (28%) were diagnosed with T1MI. Among various factors, typical chest pain (odds ratio [OR], 4.40; 95% confidence interval [CI], 1.46 to 13.24; P=0.008), high troponin I levels (OR, 1.50; 95% CI, 1.19 to 1.90; P<0.001), high cholesterol (OR, 1.01; 95% CI, 1.00 to 1.02; P=0.008), and low D-dimer levels (OR, 0.87; 95% CI, 0.77 to 0.98; P=0.027) were significantly associated with T1MI incidence. CONCLUSION: Our findings in this study indicate that typical chest pain, high levels of troponin I and cholesterol, and low levels of D-dimer were associated with the diagnosis of T1MI. Further studies are suggested to determine the cut-off values for accurate diagnosis of T1MI in the ED.