title: High-sensitive Troponin I in acute cardiac conditions: implications of baseline and sequential measurements for diagnosis of myocardial infarction.
abstract: BACKGROUND
  High-sensitive Troponin I (hsTnI) facilitates the early diagnosis of myocardial infarction (MI). However, since hsTnI has not been well characterized in non-ischemic cardiac conditions, the predictive value of hsTnI for MI remains unclear.
  
  
  METHODS
  hsTnI (ADVIA Centaur, Siemens) on admission was analyzed in 929 patients with acute cardiac condition and invasive ascertainment of coronary status by catheterization.
  
  
  RESULTS
  Hs-TnI upon presentation was higher in patients with STEMI (median 1.27 ng/mL, IQR 0.13-14.5 ng/mL) as compared to patients with Non-STEMI (0.66 ng/mL, IQR 0.10-4.0 ng/mL, p<0.001) whereas it did not differ from STEMI in Tako-Tsubo cardiomyopathy (2.57 ng/mL, IQR 0.17-8.4 ng/mL) and myocarditis (9.76 ng/mL, IQR 2.0-27.0 ng/mL). In patients with resuscitation of non-ischemic cause (0.31 ng/mL, IQR 0.06-1.3 ng/mL), acute heart failure (0.088 ng/mL, IQR 0.035-0.30 ng/mL) and hypertensive emergency (0.066 ng/mL, IQR 0.032-0.34 ng/mL), hs-TnI was elevated above the recommended threshold of 0.04 ng/mL. At this cutpoint of 0.04 ng/mL, hsTnI indicated acute MI (STEMI or Non-STEMI) with a sensitivity of 88% and a specificity of 45% (ROC-AUC 0.748). When patients with STEMI were excluded, hsTnI indicated Non-STEMI with a sensitivity of 87% and a specificity of 45% (ROC-AUC 0.725). When sequential measurements were taken into account in a restricted cohort, a maximum hsTnI of ≥0.40 ng/mL provided a sensitivity of 89% and a specificity of 85% (ROC-AUC 0.909) for Non-STEMI.
  
  
  CONCLUSIONS
  HsTnI is a sensitive, albeit unspecific marker of MI. In patients with mildly elevated hsTnI and without evidence for STEMI, we suggest serial assessment of hsTnI and a 10-fold higher cutpoint of 0.40 ng/mL before Non-STEMI is assumed.
authors.affiliation: Klinik und Poliklinik fuer Innere Medizin II, Universitaetsklinikum Regensburg, 93053 Regensburg, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Gassenmaier
authors.forename: Stefan
authors.initials: S
authors.lastname: Buchner
authors.forename: Christoph
authors.initials: C
authors.lastname: Birner
authors.forename: Carsten G
authors.initials: CG
authors.lastname: Jungbauer
authors.forename: Markus
authors.initials: M
authors.lastname: Resch
authors.forename: Kurt
authors.initials: K
authors.lastname: Debl
authors.forename: Dierk H
authors.initials: DH
authors.lastname: Endemann
authors.forename: Guenter A J
authors.initials: GA
authors.lastname: Riegger
authors.forename: Petra
authors.initials: P
authors.lastname: Lehn
authors.forename: Gerd
authors.initials: G
authors.lastname: Schmitz
authors.forename: Andreas
authors.initials: A
authors.lastname: Luchner
mesh_terms: D054058:Acute Coronary Syndrome / Q000175:diagnosis; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood*; D006328:Cardiac Catheterization; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D019210:Troponin I / Q000097:blood*
chemical_list: D015415:Biomarkers; D019210:Troponin I