title: A 3-hour diagnostic algorithm for non-ST-elevation myocardial infarction using high-sensitivity cardiac troponin T in unselected older patients presenting to the emergency department.
abstract: OBJECTIVE
  To determine if an algorithm implementing a serial high-sensitive cardiac troponin T (hs-cTnT) measurement at presentation (0 h) and at 3 hours after presentation (3h) is helpful for early diagnosis of non-ST-elevation myocardial infarction (NSTEMI) in older patients.
  
  
  METHODS
  Prospective observational cohort study.
  
  
  METHODS
  An emergency department (ED) of a city hospital covering a population of approximately 1 million in Germany.
  
  
  METHODS
  A total of 332 consecutive unselected patients were recruited, of whom 25 had one or more of the prespecified exclusion criteria and 1 had a missing hs-cTnT at 3h, resulting in a final population of 306 patients.
  
  
  METHODS
  In addition to clinical examination, hs-cTnT was measured at 0 h and 3 h. The final diagnosis of NSTEMI was adjudicated by two independent consultants and an algorithm for rule-in and rule-out of NSTEMI was developed using classification and regression tree analysis. All patients were followed-up for cardiovascular outcome within 12 months.
  
  
  RESULTS
  Among 306 patients (mean age 81 ± 6 years), 38 (12%) patients had NSTEMI. Accuracy to diagnose NSTEMI was significantly higher for hs-cTnT measurements at 3 h versus 0 h (area under the receiver operating characteristic curve [AUC] 0.88 vs. 0.82, P = .0038) and for absolute versus relative hs-cTnT delta changes (AUC 0.89 versus 0.69, P < .001). A diagnostic algorithm using hs-cTnT values at presentation and absolute delta changes values ruled-in NSTEMI in 23% and ruled-out NSTEMI in 35% of patients. For patients neither fulfilling the rule-in nor the rule-out criteria, an observational zone was established. Cumulative 1-year survival was 79.4%, 88.5%, and 99.1% in patients classified as rule-in, observational zone, and rule-out, respectively.
  
  
  CONCLUSIONS
  In older patients, serial hs-cTnT measurements and absolute delta-changes at 3h were valuable for early diagnosis of NSTEMI. An algorithm ruled-in NSTEMI in one quarter of patients with high risk and ruled-out NSTEMI in one-third with low risk.
authors: Institute for Biomedicine of Aging, Friedrich-Alexander-University, Nuremberg, Germany. philipp.bahrmann@iba.fau.de
authors: Philipp
authors: P
authors: Bahrmann
authors: Michael
authors: M
authors: Christ
authors: Anke
authors: A
authors: Bahrmann
authors: Harald
authors: H
authors: Rittger
authors: Hans Jürgen
authors: HJ
authors: Heppner
authors: Stephan
authors: S
authors: Achenbach
authors: Thomas
authors: T
authors: Bertsch
authors: Cornel C
authors: CC
authors: Sieber
mesh_terms: D000369:Aged, 80 and over; D000465:Algorithms; D003661:Decision Support Techniques; D042241:Early Diagnosis; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013997:Time Factors; D020107:Troponin T / Q000097:blood*
chemical_list: D020107:Troponin T