Comparison of MB Fraction of Creatine Kinase Mass and Troponin I Serum Levels With Necropsy Findings in Acute Myocardial Infarction

Serum levels of troponin and heart-related fraction of creatine kinase (CK-MB) mass are used as diagnostic and prognostic criteria in myocardial infarction, but the relation between those levels and the necropsy-determined size of necrosis has not been tested in human beings. In this retrospective study, 1-cm-thick transverse sections of the ventricles were cut from the base to the apex in the necropsy hearts of 27 patients aged 47 to 86 years (mean 66, median 69; 19 men). Total and necrotic areas were measured using a computer-linked image analysis system. The weights of the necrotic areas were also calculated. The correlations of the areas and weights of necrotic myocardium with the highest serum values of CK-MB mass and troponin I, which had been quantified during life by chemiluminescence immunoassays, were verified by Pearson’s test; results were considered significant at p ≤0.05. Significant correlations were detected between CK-MB mass peak and infarct size (r = 0.63, p <0.01) and weight (r = 0.69, p <0.01) and between CK-MB mass and highest troponin level (r = 0.73, p <0.01); however, the correlations between highest troponin level and myocardial infarct size (r = 0.31, p = 0.11) and weight (r = 0.35, p = 0.07) were small and nonsignificant. In conclusion, despite the well-established role of serum levels of troponin as a diagnostic tool for myocardial infarction, their highest values showed poor correlations with the extent of infarct. In contrast, the highest serum level of CK-MB mass was well correlated with myocardial infarct size.