title: The predictive value of high sensitivity-troponin velocity within the first 6h of presentation for cardiac outcomes regardless of acute coronary syndrome diagnosis.
abstract: BACKGROUND
  Low-range troponin elevations without clear coronary manifestations remain a major diagnostic challenge. We sought to determine if troponin velocity could allow for early identification of patients without an obvious cardiac diagnosis and who are at increased risk for cardiac-specific events.
  
  
  RESULTS
  All patients presenting to South Australian public hospitals between 1 September 2011 and 30 September 2012, with at least two troponin measurements during the first 6h after ED presentation were included. Diagnoses were classified as 'coronary', 'non-coronary cardiac', and 'non-cardiac' using the International Classification of Diseases 10 codes. The relationship between troponin velocity and cardiac-specific mortality and combined cardiac outcome (death and myocardial infarction) was assessed using Fine and Gray competing risk models in patients with an initial troponin <52 ng/L. Sensitivity analyses were performed using different initial and maximum troponin cut-off values. In total, 7300 patients were identified. A troponin velocity of 2.5 ng/L/h or greater in the non-cardiac (n=2793) patient group was significantly associated with an increased risk for 12-month cardiac mortality (sub-hazard ratio [SHR] 2.90, 95% CI 1.33-6.34) and combined cardiac outcome (SHR 2.08, 95% CI 1.01-4.27). This association was consistent for coronary (n=3835) and non-coronary cardiac (n=672) patient groups, and remained after sensitivity analyses.
  
  
  CONCLUSIONS
  The significant association observed across all patient groups suggests that troponin velocity could be used for early risk stratification of patients with low-range troponin elevations without clear cardiac symptoms. These results may help guide future clinical trials aimed at assessing the utility of cardiac-targeted interventions in this challenging patient population.
authors.affiliation: School of Medicine, Flinders University of South Australia, Adelaide, Australia; Department of Cardiovascular Medicine, Southern Adelaide Local Health Network, Adelaide, Australia.
authors.forename: Anthony
authors.initials: A
authors.lastname: Chuang
authors.affiliation: School of Medicine, Flinders University of South Australia, Adelaide, Australia; Department of Cardiovascular Medicine, Southern Adelaide Local Health Network, Adelaide, Australia.
authors.forename: David G
authors.initials: DG
authors.lastname: Hancock
authors.affiliation: South Australian Health and Medical Research Institute, Australia.
authors.forename: Matthew
authors.initials: M
authors.lastname: Horsfall
authors.affiliation: Department of Cardiovascular Medicine, Southern Adelaide Local Health Network, Adelaide, Australia.
authors.forename: Nasser J
authors.initials: NJ
authors.lastname: Alhammad
authors.affiliation: School of Medicine, Flinders University of South Australia, Adelaide, Australia.
authors.forename: Julia
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Department of Emergency Medicine, Royal Brisbane Hospital, Brisbane, Australia.
authors.forename: Louise
authors.initials: L
authors.lastname: Cullen
authors.affiliation: South Western Sydney Clinical School, University of New South Wales, Australia.
authors.forename: John
authors.initials: J
authors.lastname: French
authors.affiliation: School of Medicine, Flinders University of South Australia, Adelaide, Australia; Department of Cardiovascular Medicine, Southern Adelaide Local Health Network, Adelaide, Australia. Electronic address: derek.chew@flinders.edu.au.
authors.forename: Derek P
authors.initials: DP
authors.lastname: Chew
mesh_terms: D054058:Acute Coronary Syndrome / Q000097:blood* / Q000175:diagnosis* / Q000453:epidemiology; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013021:South Australia / Q000453:epidemiology; D013997:Time Factors; D016896:Treatment Outcome; D020107:Troponin T / Q000097:blood*
chemical_list: D015415:Biomarkers; D020107:Troponin T
keywords: Myocardial infarction; Risk prediction; hs-Troponin