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 Creatine Kinase isoenzyme mb (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.

Costa TN, Cassaro Strunz CM, Nicolau JC, Gutierrez PS.
Heart Institute (InCor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
Am J Cardiol. 2008 Feb 1;101(3):311-4.