Clinical variables for predicting type-1 and type-2 non-ST segment elevation myocardial infarction in those presenting with ischemic symptoms.

Introduction: The accuracy of detecting myocardial infarction (MI) has greatly improved with the advent of more sensitive assays, and this has led to etiologic subtyping. Distinguishing between type 1 and type 2 non-ST-segment elevation myocardial infarction (NSTEMI) early in the clinical course allows for the most appropriate advanced diagnostic procedures and most efficacious treatments. The purpose of this study was to investigate the predictive effect of demographic and clinical variables on predicting NSTEMI subtypes in patients presenting with ischemic symptoms.

Material and methods: We performed a single institution retrospective cohort study of patients who presented to the emergency department (ED) with ischemic signs and symptoms consistent with non-ST-segment myocardial infarction, for whom results of coronary angiography were available. We analyzed demographic, laboratory, echocardiography and angiography data to determine predictors of NSTEMI sub-types.

Results: Five hundred and forty-six patients were enrolled; 426 patients were found on coronary angiography to have type 1 acute MI (T1AMI), whereas 120 patients had type 2 acute MI (T2AMI). Age (OR per year = 1.03 (1.00, 1.05), p = 0.03), prior MI (OR = 3.50 (1.68, 7.22), p = 0.001), L/H > 2.0 (OR = 1.55 (1.12, 2.13), p = 0.007), percentage change in troponin I > 25% (OR = 2.54 (1.38, 4.69), p = 0.003), and regional wall motion abnormalities (RWMA) (OR = 3.53 (1.46, 8.54), p = 0.004) were independent predictors of T1AMI, whereas sex, race, body mass index, hypertension, end-stage renal disease (ESRD), heart failure, family history (FH) of coronary artery disease (CAD), HbA_1c, and left ventricular ejection fraction (LVEF) were not.

Conclusions: Key clinical variables such as age, prior MI, L/H ratio, percentage change in troponin I, and presence of RWMA on echocardiogram may be utilized as significant predictors of T1AMI in patients presenting with ischemic symptoms to the ED.