CK-MB isoforms for early risk stratification of emergency department patients

The potential clinical utility of single sample CK-MB isoforms measurement for early risk stratification of Emergency Department (ED) patients with possible myocardial ischemia was evaluated among 405 patients presenting to two urban EDs. Clinical and serologic data were prospectively collected and the occurrence of adverse events (AEs) and myocardial infarction (MI) during the 14-day outcome period was recorded and utilized to calculate and compare relative risks (RR) and predictive values of isoforms and CK-MB alone. Among the 405 patients, 67 accrued 105 AEs. Both isoforms and CK-MB alone were predictive of AEs with RR of 3.32 (2.09, 5.27) and 6.28 (4.64, 8.52), respectively. Isoforms had higher sensitivity for AEs compared to CK-MB (65.7% [54.3, 77.0] vs. 14.9% [6.4, 23.5]; p < 0.01) but lower specificity (69.2% [64.3, 74.2] vs. 99.7% [99.1,100.0]; p < 0.01). Isoforms' superior sensitivity allowed identification of many high risk patients missed by CK-MB alone. Further, for the prediction of MI, isoforms had superior diagnostic sensitivity and equivalent specificity. This investigation supports the emergency department use of early, single sample CK-MB isoform testing. (C) 2000 Elsevier Science B.V.