CJEM Articles: creatine kinase

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  • Discordant creatine kinase and cardiac troponin T in the workup of acute coronary syndrome
    January 2010 12 1
    J. Fan, J. Kanji

    A 55-year-old man presented to the emergency department (ED) following 2 episodes of typical cardiac chest pain and nonspecific electrocardiogram findings. His serial cardiac marker assays revealed an elevated total creatine kinase (CK) and 2 negative cardiac troponin levels. Because of a high clinical suspicion of acute coronary syndrome, a total creatine kinase MB mass was obtained and found to be elevated. Subsequent cardiac angiography demonstrated a significantly flow limiting coronary artery lesion, and stenting was performed. This case demonstrates that simultaneous CK and troponin measurements may have utility in selected ED patients with chest pain. The interpretation of discordant CK and troponin levels is discussed.

  • Diagnostic parameters of CK-MB and myoglobin related to chest pain duration
    September 2002 4 5
    Grant Innes, James Christenson, James Hoekstra, Nathan Every, Paul Frederick, Raymond E. Jackson, Tiepu Liu, W. Brian Gibler, W. Douglas Weaver

    Objective: Cardiac marker sensitivity depends on chest pain duration at the time of sampling. Our objective was to estimate the sensitivity, specificity, and likelihood ratios of early CK-MB and myoglobin assays in patients presenting to the emergency department (ED) with nondiagnostic ECGs, stratified by the duration of ongoing chest pain at the time of ED assessment.
    Methods: This was a prospective observational study carried out in 10 US and 2 Canadian EDs. Patients >25 years of age with ongoing chest pain and nondiagnostic ECGs were stratified by pain duration (0-4 h, 4-8 h, 8-12 h, >12 h). CK-MB and myoglobin assays were drawn at T = 0 (ED assessment) and T = 1 hr. Patients were followed for 7-14 days to identify all cases of acute myocardial infarction (AMI). ED test results were correlated with patient outcomes.
    Results: Of 5005 eligible patients, 565 had AMI. Pain duration was 0-4 h in 3014 patients, 4-8 h in 961, 8-12 h in 487, and >12 h in 543. Marker sensitivity increased with pain duration, ranging from 28%-77% for CK-MB and 39%-73% for myoglobin. The maximal sensitivity achieved by a T = 0 assay was 73%, and this was in patients with 8-12 or >12 h of ongoing pain. No combination of tests achieved 90% sensitivity in any pain duration strata.
    Conclusions: Regardless of chest pain duration, single assays and early serial markers (0+1 hr) do not rule out AMI; therefore, serial assays over longer observation periods are required. Likelihood ratios derived in this study will help physicians who use Bayesian analysis to determine post-test AMI likelihood in patients with chest pain.