Comparison of the diagnostic performance of two rapid bedside biochemical assays in the early detection of acute myocardial infarction

Abstract

Background: New biochemical markers have been recently proposed as potential aids in the diagnosis of myocardial infarction. Assessment of these markers in real time by near-patient testing would allow more rapid decisions regarding critical therapeutic interventions. Hypothesis: The diagnostic performance of two qualitative, whole blood assays for measurement of myoglobin/creatine kinase (CK)-MB mass (CARDIAC STATus(TM)) and cardiac troponin T (TropT®) was compared. Their potential in optimizing the rule-in of patients with infarction in order to initiate revascularization therapies was also evaluated. Methods: A group of 101 patients admitted to the hospital within 12 h from onset of symptoms suggestive of myocardial infarction was studied. A first blood sample was drawn in all patients immediately after admission. In patients not receiving reperfusion therapy (n = 61), three additional samples were also obtained 2, 4, and 6 h later. Results: CARDIAC STATus showed good performance in patients with an admission time > 2 h from onset of pain (diagnostic efficiency, 71- 100%). Conversely, TropT was not sensitive enough for acceptable efficiency. In a subset of 39 patients admitted within 6 h who did not meet standard enrollment criteria for thrombolysis, CARDIAC STATus allowed early detection of almost 50% of infarcts, enabling a significant implementation of alternative revascularization therapies. Conclusions: In patients admitted to the coronary care unit on the basis of case history and clinical examination, CARDIAC STATus assay is more effective than TropT in the early diagnosis of infarction, providing a valuable aid to cardiologists for confirming a suspected infarction rapidly, thus allowing, if indicated, recourse to revascularization therapy in clinically uncertain cases.