Missed acute cardiac ischemia in the ED: limitations of diagnostic testing.
ABSTRACT Correctly identifying and appropriately triaging patients who present to the ED with the broad range of symptoms suggestive of acute cardiac ischemia (ACI: unstable angina pectoris [UAP] and acute myocardial infarction [AMI]) remains one of the greatest challenges in EM. Although a number of diagnostic technologies have been described to aid in this triage process, each of these tests or technologies has limitations. We report a case series in which either the use of adjuncts with unknown performance or tests with known but not considered limitations could have contributed to the failure to appropriately triage and treat patients with ACI. Each case illustrates different aspects of this clinical challenge. One case illustrates the hazards of reliance on a single set of negative cardiac biomarkers. The limitations of a negative exercise electrocardiographic stress test (ETT) are illustrated in the second case. Finally, the limitations of a negative coronary angiogram, the "gold standard" test for symptomatic coronary artery disease, are discussed. We review the literature on technologies to aid in the evaluation of patients who present to the ED with symptoms suggestive of ACI.
Article: Beckman Access versus the Bayer ACS:180 and the Abbott AxSYM cardiac Troponin-I real-time immunoassays: an observational prospective study.[show abstract] [hide abstract]
ABSTRACT: BACKGROUND: Reliability of cardiac troponin-I assays under real-time conditions has not been previously well studied. Most large published cTnI trials have utilized protocols which required the freezing of serum (or plasma) for delayed batch cTnI analysis. We sought to correlate the presence of the acute ischemic coronary syndrome (AICS) to troponin-I values obtained in real-time by three random-mode analyzer immunoassay systems: the Beckman ACCESS (BA), the Bayer ACS:180 (CC) and the Abbott AxSYM (AX). METHODS: This was an observational prospective study at a university tertiary referral center. Serum from a convenience sampling of telemetry patients was analyzed in real-time for troponin-I by either the BA-CC (Arm-1) or BA-AX (Arm-2) assay pairs. Presence of the AICS was determined retrospectively and then correlated with troponin-I results. RESULTS: 100 patients were enrolled in Arm-1 (38 with AICS) and 94 in Arm-2 (48 with AICS). The BA system produced 51% false positives in Arm-1, 44% in Arm-2, with negative predictive values of 92% and 100% respectively. In Arm-1, the BA and the CC assays had sensitivities of 97% and 63% and specificities of 18% and 87%. In Arm-2, the BA and the AX assays had sensitivities of 100% and 83% and specificities of 11% and 78%. CONCLUSIONS: In real-time analysis, the performance of the AxSYM and ACS:180 assay systems produced more accurate troponin-I results than the ACCESS system.BMC Emergency Medicine 08/2004; 4(1):2.