MP46: Creatine kinase in the emergency department: antiquated relic or useful adjunct in diagnosis of NSTEMI: A systematic review

Abstract

Introduction: The diagnosis of non-ST elevated myocardial infarction (NSTEMI) depends on a combination of history, ECG and cardiac biomarkers. Many hospitals continue to automatically order less sensitive and specific biomarkers such as Creatine Kinase (CK) alongside cardiac Troponin (cTn) as part of an extended panel of bloodwork for work-up of patients with suspected NSTEMI. Methods: We undertook a systematic review to assess the usefulness of CK measurements in addition to cTnI in NSTEMI diagnosis. Medline, EMBASE and Cochrane databases were searched from 1995 until May 31, 2018. We added additional articles after reviewing the reference list of pertinent articles and consulting experts. A total of 1123 papers were screened, of which 8 were included in the final analysis. These papers all compared CK and troponin (TnI) testing in the diagnosis of NSTEMI. Results: Of the 8 papers included in the analysis none showed CK having a greater sensitivity or specificity than the TnI assays. Furthermore, no paper originally published evidence of CK diagnosing NSTEMI when Troponin was negative. One author, when contacted, described 10% of patients diagnosed with NSTEMI as having discordant data (eg. +CK, -Troponin). However, the outcome data such as angiography and echocardiography were not available for these patients, making definitive diagnosis unclear. Conclusion: Troponin has consistently shown to have greater sensitivity and specificity than CK in the diagnosis of NSTEMI with CK adding no improvements in diagnosis. We believe CK should not be used in the emergency department work-up for NSTEMI diagnosis.