title: Challenging the 99th percentile: A lower troponin cutoff leads to low mortality of chest pain patients.
abstract: BACKGROUND
  Rule-out of non-ST-elevation myocardial infarction is based on consecutive measurements of cardiac troponins using the 99th percentile of the respective assay as cutoff. The new ESC guidelines alternatively offer rapid 1h algorithms with lower cutoffs than the 99th percentile for rule-out of non-ST-elevation myocardial infarction. We aimed to compare a recently introduced 1h algorithm based on a high-sensitivity cardiac troponin I (hs-TnI) cutoff of 6ng/L at 0h and 1h to the current standard of care using the 99th percentile (27ng/L) as cutoff with reference to follow-up events in a large chest pain cohort.
  
  
  METHODS
  Hs-TnI was measured at three time points (0h, 1h and 3h) in 1625 patients presenting with suspected myocardial infarction to the emergency department of the University-Medical Center Hamburg-Eppendorf. Seventy-five patients with ST-elevation myocardial infarction were excluded from the analysis. All-cause mortality, cardiac death, acute myocardial infarction, revascularization and cardiac rehospitalization after 12months were assessed.
  
  
  RESULTS
  Patients ruled out by the 1h algorithm showed significantly less cardiac rehospitalizations (12.84% vs. 17.66%; p<0.001), and overall mortality (1.30% vs 3.46%, p<0.001) compared to using the 99th percentile as cutoff. The majority of deaths were caused by non-cardiac reasons. Cardiac deaths were rare using the 1h algorithm (0.21%).
  
  
  CONCLUSIONS
  The commonly used 99th percentile as cutoff neglects patients with a high risk in the setting of acute chest pain.
  
  
  BACKGROUND
  www.clinicaltrials.gov (NCT02355457).
authors.affiliation: Department of General and Interventional Cardiology, University Heart Center Hamburg, Martinistrasse 52, 20246 Hamburg, Germany. Electronic address: n.soerensen@uke.de.
authors.forename: Nils Arne
authors.initials: NA
authors.lastname: Sörensen
authors.affiliation: Department of General and Interventional Cardiology, University Heart Center Hamburg, Martinistrasse 52, 20246 Hamburg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Johannes Tobias
authors.initials: JT
authors.lastname: Neumann
authors.affiliation: Department of General and Interventional Cardiology, University Heart Center Hamburg, Martinistrasse 52, 20246 Hamburg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Francisco
authors.initials: F
authors.lastname: Ojeda
authors.affiliation: Department of General and Interventional Cardiology, University Heart Center Hamburg, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Tjark
authors.initials: T
authors.lastname: Schwemer
authors.affiliation: Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany; Clinical Chemistry and Blood Coagulation Research, Department of Molecular Medicine and Surgery, Karolinska University Hospital, Solna (L1:00), SE-171 76, Stockholm, Sweden.
authors.forename: Thomas
authors.initials: T
authors.lastname: Renné
authors.affiliation: Department of General and Interventional Cardiology, University Heart Center Hamburg, Martinistrasse 52, 20246 Hamburg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Renate B
authors.initials: RB
authors.lastname: Schnabel
authors.affiliation: Department of General and Interventional Cardiology, University Heart Center Hamburg, Martinistrasse 52, 20246 Hamburg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Tanja
authors.initials: T
authors.lastname: Zeller
authors.affiliation: Department of General and Interventional Cardiology, University Heart Center Hamburg, Martinistrasse 52, 20246 Hamburg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Mahir
authors.initials: M
authors.lastname: Karakas
authors.affiliation: Department of General and Interventional Cardiology, University Heart Center Hamburg, Martinistrasse 52, 20246 Hamburg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Blankenberg
authors.affiliation: Department of General and Interventional Cardiology, University Heart Center Hamburg, Martinistrasse 52, 20246 Hamburg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Westermann
mesh_terms: D000208:Acute Disease; D000368:Aged; D000465:Algorithms; D015415:Biomarkers / Q000097:blood; D002423:Cause of Death / Q000639:trends; D002637:Chest Pain / Q000097:blood / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D019210:Troponin I / Q000097:blood*
chemical_list: D015415:Biomarkers; D019210:Troponin I
keywords: 99th percentile; Acute coronary syndrome; Outcome; Troponin