title: Prognostic role of highly sensitive cardiac troponin I in patients with systolic heart failure.
abstract: BACKGROUND
  Cardiac troponin T (cTnT) and cardiac troponin I (cTnI) are useful biomarkers in patients with chronic heart failure (CHF). However, the clinical use has limitations due to the low sensitivity of a conventional commercial assay system. Recently, a high sensitive-cTnI (hs-cTnI) commercial assay has become available.
  
  
  METHODS
  To compare the prognostic value of cTnT and hs-cTnI, we measured hemodynamic parameters and serum levels of cTnT, hs-cTnI and N-terminal pro-brain natriuretic peptide (NT-proBNP)in 258 consecutive CHF patients and then followed these patients for a mean period of 2.6 years. In both assays of cTnT and hs-cTnI, the lowest concentration at which the coeffi cient of variation was < or =10% were 0.03 ng/mL, respectively. Therefore, in the present study, an elevated cTnT or cTnI test was defined as a level of > or =0.03 ng/mL.
  
  
  RESULTS
  During long-term follow up, there were 20 cardiac deaths. In 258 CHF patients, serum cTnT were elevated (> or =0.03 ng/mL) in 32 patients (12%) and serum hs-cTnI was elevated (> or =0.03 ng/mL) in 112 patients (43%). On stepwise multivariate analyses, high plasma NT-proBNP (> or =627 pg/mL, P = .0063) and hs-cTnI (> or =0.03 ng/mL) (P = .016) were independent significant prognostic predictors but cTnT (> or =0.03 ng/mL) was not. The hazard ratio for mortality of patients with high plasma NT-proBNP (> or =627 pg/mL) and hs-cTnI (> or =0.03 ng/mL) was 5.74 (95% CI, 2.33-14.28, P < .0001) compared to that of those with low NT-proBNP (<627 pg/mL) or hs-cTnI (<0.03 ng/mL).
  
  
  CONCLUSIONS
  These findings indicate that a high plasma concentration of hs-cTnI is an independent and useful prognostic predictor in patients with CHF.
authors.affiliation: Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan. tutamoto@belle.shiga-med.ac.jp
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Tsutamoto
authors.forename: Chiho
authors.initials: C
authors.lastname: Kawahara
authors.forename: Keizo
authors.initials: K
authors.lastname: Nishiyama
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamaji
authors.forename: Masanori
authors.initials: M
authors.lastname: Fujii
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Minoru
authors.initials: M
authors.lastname: Horie
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D005260:Female; D054143:Heart Failure, Systolic / Q000097:blood* / Q000175:diagnosis / Q000401:mortality*; D006334:Heart Function Tests; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D013318:Stroke Volume / Q000502:physiology; D016019:Survival Analysis; D019210:Troponin I / Q000097:blood*
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; D019210:Troponin I; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain