Abstract 1728: Creatine Kinase-MB Enzyme Elevation is a Powerful Independent Predictor of All cause Mortality in Non-ST Segment Elevation Acute Coronary Syndrome
INTRODUCTION: Patients who present with an acute coronary syndrome (ACS) are routinely evaluated with cardiac biomarkers. Cardiac troponin (cTn) has replaced creatine-kinase MB (CKMB). The utility of CKMB isoenzyme as an initial diagnostic biomarker has been questioned.
HYPOTHSIS: We assessed the hypothesis that CKMB may still be clinically relevant for the diagnosis and assessment of risk in patients with ACS.
METHODS: 8654 patients who presented during 2000–2003, with a non ST segment elevation (NSTE) ACS had cardiac biomarkers measured upon admission and every 8 hours for 3 sets. Data was collected in all patients for up to 5 years with a mean of 1269 days post hospitalization. Four combinations of marker assay were examined: CKMB+/ cTn+, CKMB+/cTn−, CKMB−/cTn+, and CKMB−/cTn−. The influence of CKMB(+) on mortality during follow-up was evaluated.
RESULTS: Of 8654 patients, 3647 (42%) had elevated CKMB in any of the three sets of cardiac biomarkers during their first hospitalization day. After adjustment for cTn(+) and coronary risk factors the CKMB isoenzyme was found to be an independent predictor of all cause mortality. The greatest number of deaths occurred within the first 30 days in patients with all four biomarker combinations. CKMB(+) patients, however, were found to have a higher percentage of deaths, even in the presence of cTn(−).
CONCLUSION: NSTE ACS patients who are CKMB(+) have a greater all-cause mortality regardless of cTn status. It may be beneficial to continue measuring CKMB in order to risk stratify NSTE ACS patients.