title: Direct comparison of cardiac troponin I and cardiac troponin T in the detection of exercise-induced myocardial ischemia.
abstract: BACKGROUND
  It is unknown, whether cardiac troponin (cTn) I or cTnT is the preferred biomarker in the detection of exercise-induced myocardial ischemia.
  
  
  METHODS
  We investigated patients with suspected myocardial ischemia referred for exercise or pharmacological rest/stress myocardial perfusion single-photon emission computed tomography (SPECT) to directly compare the diagnostic accuracy of high-sensitivity cTnI (hs-cTnI) and hs-cTnT. Diagnostic performance was analyzed separately according to stress modality. Hs-cTnI and hs-cTnT were measured before, immediately after, as well as 2h and 4h after maximal exercise in a blinded fashion. Further, all clinical information available to the treating cardiologist was used to quantify the clinical judgment regarding the presence of myocardial ischemia using a visual analog scale twice: once prior and once after stress-testing. The presence of stress-induced myocardial ischemia was adjudicated using SPECT combined with coronary angiography findings.
  
  
  RESULTS
  A total of 403 consecutive patients were enrolled in our study, of which 229 underwent exercise stress and 174 patients pharmacological stress. Exercise-stress-induced myocardial ischemia was detected in 90 patients (39.3% of 229). Levels of hs-cTnI and hs-cTnT were both significantly higher at all time-points examined in patients with exercise-induced myocardial ischemia as compared to patients without myocardial ischemia (all p<0.001). Correlation of hs-cTnI and hs-cTnT was high in direct comparison of time-points (Spearman's rho all ≥0.7). The AUCs for baseline/peak/2h/4h for hs-cTnI and hs-cTnT were 0.71/0.71/0.72/0.69 vs. 0.74/0.73/0.71/0.72, respectively (all p=ns for hs-cTnI versus hs-cTnT). In patients undergoing pharmacological stress, the AUCs for baseline/peak/2h/4h for hs-cTnI and hs-cTnT were 0.66/0.66/0.68/0.67 and 0.61/0.62/0.64/0.59, respectively (all p=ns for hs-cTnI versus hs-cTnT). Also the combinations including clinical judgment or changes during serial sampling were similar for hs-cTnI and hs-cTnT (all p=ns).
  
  
  CONCLUSIONS
  Hs-cTnI and hs-cTnT provide comparable diagnostic information regarding exercise-induced myocardial ischemia. Overall, their diagnostic accuracy seems moderate.
  NCT01838148.
authors.affiliation: Department of Cardiology, University Hospital Basel, Switzerland; Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland.
authors.forename: Seoung Mann
authors.initials: SM
authors.lastname: Sou
authors.affiliation: Department of Cardiology, University Hospital Basel, Switzerland; Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Puelacher
authors.affiliation: Department of Cardiology, University Hospital Basel, Switzerland; Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland.
authors.forename: Raphael
authors.initials: R
authors.lastname: Twerenbold
authors.affiliation: Department of Cardiology, University Hospital Basel, Switzerland; Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland.
authors.forename: Max
authors.initials: M
authors.lastname: Wagener
authors.affiliation: Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland.
authors.forename: Ursina
authors.initials: U
authors.lastname: Honegger
authors.affiliation: Department of Cardiology, University Hospital Basel, Switzerland; Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland.
authors.forename: Tobias
authors.initials: T
authors.lastname: Reichlin
authors.affiliation: Department of Cardiology, University Hospital Basel, Switzerland; Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Schaerli
authors.affiliation: Department of Cardiology, University Hospital Basel, Switzerland; Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland.
authors.forename: Gil
authors.initials: G
authors.lastname: Pretre
authors.affiliation: Department of Cardiology, University Hospital Basel, Switzerland; Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland.
authors.forename: Roger
authors.initials: R
authors.lastname: Abächerli
authors.affiliation: Department of Cardiology, University Hospital Basel, Switzerland; Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland.
authors.forename: Cedric
authors.initials: C
authors.lastname: Jaeger
authors.affiliation: Department of Cardiology, University Hospital Basel, Switzerland; Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland.
authors.forename: Maria
authors.initials: M
authors.lastname: Rubini Gimenez
authors.affiliation: Division of Nuclear Medicine, University Hospital Basel, Switzerland.
authors.forename: Damian
authors.initials: D
authors.lastname: Wild
authors.affiliation: Department of Laboratory Medicine, University Hospital Basel, Switzerland.
authors.forename: Katharina M
authors.initials: KM
authors.lastname: Rentsch
authors.affiliation: Department of Cardiology, University Hospital Basel, Switzerland; Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Zellweger
authors.affiliation: Department of Cardiology, University Hospital Basel, Switzerland; Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Switzerland. Electronic address: Christian.Mueller@usb.ch.
authors.forename: Christian
authors.initials: C
authors.lastname: Mueller
mesh_terms: D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D017202:Myocardial Ischemia / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D019210:Troponin I / Q000097:blood*; D020107:Troponin T / Q000097:blood*
chemical_list: D019210:Troponin I; D020107:Troponin T
keywords: Exercise-induced myocardial ischemia