Risk prediction in patients with chest pain: early assessment by the combination of troponin I results and electrocardiographic findings

Abstract

To evaluate the prognostic value of point of care troponin I (TnI) results in combination with findings from the admission electrocardiogram (ECG) in patients with chest pain. Rapid measurements of TnI were performed in 191 consecutive patients with chest pain and a non-diagnostic ECG for myocardial infarction. Within 6 h from admission, maximum TnI elevations of > or = 0.07 microg/l and > or = 0.1 microg/l were noted in 59 and 39% of all patients, respectively. TnI elevations in the range of 0.07-0.09 microg/l were found in many patients with diagnoses other than acute coronary syndrome. By 6-month follow-up, cardiac death had occurred in 7.1 and 11% of patients with maximum TnI > or = 0.07 microg/l and > or = 0.1 microg/l, respectively and myocardial reinfarction was documented in 12 and 15%, respectively. ST-segment depression on the admission ECG was present in 16% of all patients and was the electrocardiographic abnormality with the highest risk (cardiac death 7.7%, myocardial reinfarction 15%). The combination of TnI > or = 0.1 microg/l and ST-segment depression or an abnormal admission ECG in general allowed the identification of patients at low, intermediate and high cardiac risk, 3 h after admission. A threshold of TnI > or = 0.1 microg/l corresponding to the 10% coefficient of variation is prognostically most suitable for prediction of cardiac events in patients with chest pain. The combination of TnI results and findings from the admission ECG improves prognostic assessment and allows early and reliable risk stratification in this patient population.