Comparison of Troponin T to Creatine Kinase and to Radionuclide Cardiac Imaging Infarct Size in Patients With ST-Elevation Myocardial Infarction Undergoing Primary Angioplasty

Troponin is used mainly for detection of minor myocardial damage, whereas repeated measurements of creatine kinase (CK) and myocardial band (CK-MB) are used for assessing infarct size in patients with myocardial infarction. The purpose of this study was to correlate peak level and area under the curve (AUC) of troponin T to that of CK and CK-MB and with single-photon emission computed tomographic infarct size and left ventricular function in patients with ST elevation myocardial infarction. In this multicenter study (29 centers, 5 countries), we included 267 patients who underwent primary coronary intervention within 6 hours of onset of symptoms. All had repeated measurements of troponin T, CK, and CK-MB. Infarct size and left ventricular function were assessed by single-photon emission computed tomography performed on days 7 and 30. Mean infarct sizes were 14% on day 7 and 10% on day 30, and mean ejection fractions were 42% on day 7 and 45% on day 30 after the acute infarct. Very high correlation (r >0.85, Spearman correlation) was found between peak level and AUC of troponin T, CK, and CK-MB. Similar high correlation was found between peak level and AUC of troponin, CK, and CK-MB with single-photon emission computed tomographic infarct size (r >0.70). In conclusion, based on the results of this multicenter study, we suggest that peak levels and AUC of troponin are as accurate as CK and CK-MB in estimating myocardial infarct size.