The evaluation of cTnT/CK-MB ratio is as a predictor of change in cardiac function after myocardial infarction

Abstract

Objective: Cardiac enzymes that are released during acute myocardial infarction (AMI) are of prognostic importance. This study aimed to investigate the relationship between cardiac troponin T (cTnT) and creatine kinase myocardial band (CK-MB) release during AMI and 6-month post-AMI left ventricular (LV) function, as assessed by magnetic resonance imaging. Methods: This prospective cohort observational study included 131 adult patients (113 males, 18 females, mean age 53.8 (8.6) years) who had been diagnosed with a new ST-segment elevation AMI (STEMI) in the emergency department. Cardiac enzymes were assessed by serial measurements. Blood samples obtained at 12 h post-AMI were included in the analysis. The reference value for CK-MB was 2–25 U/L, while for troponin it was - 0.1 ng/mL. Values above the reference limit were accepted as positive. Patients underwent cardiovascular magnetic resonance at 2 weeks and 6 months post-AMI. LV stroke volume was quantified as LV EDV – LV ESV, and ejection fraction (EF) was determined with the following equation: EF = [(LV EDV – LV ESV)/LV EDV] × 100. Adverse remodeling was defined based on the threshold values that are commonly accepted for changes in the LV end-diastolic volume (∆LV-EDV, &qt;10%) and LV end-systolic volume (∆LV-ESV, &qt;12%). Results: All of the patients were cTnT- and CK-MB-positive at 12 h. There was no found significant difference between both groups regarding the risk factors of coronary artery disease (including diabetes mellitus, hypertension, hyperlipidemia and smoking).  Adverse cardiac remodeling was observed in 32.1% (n = 42) of the patients. cTnT/CK-MB was determined to be an independent predictor of the ΔLV-EDV (β ( SE = 0.55 ( 0.08, p<0.001), ΔLV-ESV (β ( SE = 1.12 ( 0.28, p<0.001), and adverse remodeling (OR = 1.13, p<0.001). The cTnT/CK-MB ratio was able to predict adverse remodeling with 85.7% sensitivity and 74.2% specificity (area under the ROC curve (AUC) = 0.856, p<0.001). The cTnT levels were able to predict adverse remodeling with 73.8% sensitivity and 78.7% specificity (AUC = 0.796, p<0.001). CK-MB did not significantly predict adverse remodeling (AUC = 0.516, (p=0.758). Conclusion: The cTnT/CK-MB ratio was superior to its components in predicting changes in LV function after STEMI. The cTnT/CK-MB ratio can be used in clinical practice for risk stratification and treatment optimization.