Prognostic Significance of Admission Troponin T Concentrations in Patients With Myocardial Infarction

Abstract

Background New, highly specific cardiac structural proteins can now be measured. The early presence of one of these proteins, troponin T, has been found to have important prognostic significance in patients with unstable angina pectoris. The prognostic significance of its presence on admission was assessed in patients with myocardial infarction. Methods and Results Two hundred forty patients admitted with myocardial infarction were studied and followed prospectively for a median of 3 years. The prognostic significance of an admission troponin T concentration ≥0.2 ng/mL for subsequent cardiac death and/or reinfarction was assessed and compared with other variables in a regression model. Any detectable troponin T on admission was associated with a worse prognosis on follow-up. An admission concentration of ≥0.2 ng/mL was associated with a higher risk of subsequent cardiac death (χ 2 , 13.3; P =.0002) and death or nonfatal reinfarction (χ 2 , 16; P =.00006). The excess risk was seen primarily in patients with admission ECG ST-segment elevation (cardiac death χ 2 , 9.7; P =.001; death or nonfatal reinfarction χ 2 , 10.3; P =.001). In a stepwise regression model for cardiac death or nonfatal reinfarction, troponin T was superior to most of the other variables entered in both myocardial infarction subgroups. Conclusions The presence of admission troponin T in patients with myocardial infarction defines a subgroup, particularly those with ST-segment elevation, at increased risk of subsequent cardiac events and identifies a group that may benefit from alternative early management strategies.