Relationships between Myocardial Damage Biomarkers with Infarct Size and Ejection Fraction Impairment Assessed by Cardiac Magnetic Resonance

Background: Acute myocardial infarction (AMI) is the leading cause of morbidity and mortality worldwide. The final infarct size (FIS) and left ventricular ejection fraction (LVEF) are the greatest predictors of post-AMI mortality, with cardiac magnetic resonance (CMR) being the gold standard method for their measurement. Myocardial damage biomarkers, such as creatine kinase (CK) and myocardial creatine kinase (CKMB) are currently used to diagnose AMI and estimate the myocardial damage extent. It would be plausible to use them as predictors of FIS and LVEF; however, current evidence is not available up to date.

Objective: To determine the potential power of plasma CK and CKMB levels as predictors of FIS and LVEF impairment, respectively, on the basis of their correlation in patients undergoing primary coronary angioplasty (PCA) following ST-elevation acute myocardial infarction (STEMI).

Methodology: A retrospective analysis of PREVEC Trial (ISRCTN registry: 56034553), a multicentric, randomized, double-blind clinical study was performed. Sixty-seven patients with STEMI scheduled for PCA were enrolled. The CMR was performed 7-15 days after the event. Three radiologists blinded to clinical information measured FIS and LVEF. Total CK and CKMB were measured in peripheral venous blood at 6-8 hours after PCA. Correlation coefficient were obtained, and the tests were considered significant with a p value <0.05. The software GraphPrism 6.0 was used for the statistical analysis.

Results: A significant positive correlation was obtained between levels of cardiac biomarkers and FIS [total CK (r-square 0.3, p<0.0001) and CK MB (r-square 0.15, p<0.0027)]. In addition, the levels of these biomarkers showed a significant negative correlation with LVEF [total CK (r-square 0.3, p<0.0001) and CK MB (r-square 0.18, p<0.0012)].

Conclusion: These results are consistent with the view that the myocardial damage biomarkers CK and CKMB are reliable as predictors of FIS and LVEF measured by CMR in post-AMI patients. These data suggest that these biomarkers could be included in future Risk Scores.