Abstract
Background The clinical implications of applying the new criteria of acute myocardial infarction (AMI) with cardiac troponins in terms of their diagnostic and prognostic impact in patients with suspected acute coronary syndromes (ACS) have not been well evaluated. Methods and Results The study group comprised 973 consecutive patients who were diagnosed as having ACS with or without ST elevation (STE). They were divided into 3 groups: unstable angina (UA) group (n=195) representing patients with no significant elevations of creatine kinase (CK) and troponin T (TnT); TnT-myocardial infarction (MI) group (n=170) with TnT elevation and no CK elevation (additionally detected AMI by the new criteria); CK-MI group (n=608) with significant elevation of CK (AMI by the old criteria). In the TnT-MI group, 140 (76%) patients had non-STE ACS. In-hospital mortality rates for STE ACS were 0%, 2.5% and 9.7% in the UA, TnT-MI and CK-MI groups, respectively. The corresponding values for non-STE ACS were 1.8%, 4.6%, and 16.5%, respectively (p<0.0001), suggesting a pivotal role of TnT. In multiple logistic regression analysis, significant CK elevation was selected as an independent predictor of in-hospital death in concurrence with age ≥75 years, prior MI, shock and low left ventricular ejection fraction in non-STE ACS. Conclusions The new criteria result in a substantial increase in the diagnosis of AMI from non-STE ACS in particular. They assist greatly in detailed risk stratification of ACS patients, notably in cooperation with the old CK criteria. (Circ J 2005; 69: 774 - 779)
