High sensitivity troponin: Does the 50% delta change alter clinical outcomes in chest pain presentations to the emergency room?

BackgroundThe National Heart Foundation (NHF) and Cardiac Society of Australia and New Zealand (CSANZ) Acute Coronary Syndrome (ACS) guidelines recommend the use of a high sensitivity troponin assay (hsTrop) in the assessment of patients presenting with ACS. A troponin delta of 50% compared with the previously recommended 20% is advocated by the guidelines to aid in the clinical diagnosis of ACS. We sought to determine the clinical impact of the updated recommendation to use 50% troponin delta for patients presenting with chest pain to the emergency department.MethodWe retrospectively collected data for all patients > 18 years presenting with chest or abdominal pain with a hsTrop test performed between January-June 2012. Patients with a STEMI, lacked serial hsTrop, were on dialysis or had trauma-related pain were excluded.ResultsOf the 1054 eligible patients, 422 (40%) with serial hsTrop had at least one abnormal troponin (> 14 ng/ml). 73 (6.9%) fell within 20-50%. Twenty-seven had clinical or ECG evidence suggestive of ACS and were referred for further cardiac investigations. Of the remainder, five patients were medically managed for ACS, 38 patients with non-cardiac chest pain had no further tests. At 1 year follow-up, of the patients that did not undergo further investigations, 6 patients represented with ACS; there was no cardiac mortality.ConclusionOur data showed a number of patients that would be potentially missed with the implementation of a 50% troponin. However, this loss of sensitivity was mitigated by the use of clinical acumen.