title: High-sensitivity troponin T predicts infarct scar characteristics and adverse left ventricular function by cardiac magnetic resonance imaging early after reperfused acute myocardial infarction.
abstract: BACKGROUND
  Late gadolinium enhancement cardiac magnetic resonance imaging (CMRI) is the current standard for evaluation of myocardial infarct scar size and characteristics. Because post-ST-segment elevation myocardial infarction (STEMI) troponin levels correlate with clinical outcomes, we sought to determine the sampling period for high-sensitivity troponin T (hs-TnT) that would best predict CMRI-measured infarct scar characteristics and left ventricular (LV) function.
  
  
  RESULTS
  Among 201 patients with first presentation with STEMI who were prospectively recruited, we measured serial hs-TnT levels at admission, peak, 24 hours, 48 hours, and 72 hours after STEMI. Indexed LV volumes, LV ejection fraction (LVEF) and infarct scar characteristics (scar size, scar heterogeneity, myocardial salvage index, and microvascular obstruction) were evaluated by CMRI at a median of 4 days post-STEMI. Peak and serial hs-TnT levels correlated positively with early indexed LV volumes and infarct scar characteristics, and negatively correlated with myocardial salvage index and LVEF. Both 48- and 72-hour hs-TnT levels similarly predicted "large" total infarct scar size (odds ratios [ORs] 3.08 and 3.53, both P < .001), myocardial salvage index (ORs 1.68 and 2.30, both P < .001), and LVEF <40% (ORs 2.16 and 2.17, both P < .001) on univariate analyses. On multivariate analyses, 48- and 72-hour hs-TnT levels independently predicted large infarct scar size (ORs 2.05 and 2.31, both P < .001), reduced myocardial salvage index (OR 1.39 [P = .031] and OR 1.55 [P = .009]), and LVEF <40% (OR 1.47 [P = .018] and OR 1.43 [P = .026]). All measured hs-TnT levels had a modest association and similar capacity to predict microvascular obstruction.
  
  
  CONCLUSIONS
  Levels of hs-TnT at 48 and 72 hours, measured during the "plateau phase" post-STEMI, predicted infarct scar size, poor myocardial salvage, and LVEF. These levels also correlated with scar heterogeneity and microvascular obstruction post-STEMI. Since ascertaining peak levels after STEMI is challenging in routine practice, based on the biphasic kinetics of hs-TnT, a measurement at 48 to 72 hours (during the plateau phase) provides a useful and simple method for early evaluation of LV function and infarct scar characteristics.
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, New South Wales, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, New South Wales, Australia. Electronic address: nguyenletuan@hotmail.com.
authors.forename: Tuan L
authors.initials: TL
authors.lastname: Nguyen
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, New South Wales, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, New South Wales, Australia.
authors.forename: Justin A K
authors.initials: JA
authors.lastname: Phan
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, New South Wales, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, New South Wales, Australia.
authors.forename: Leia
authors.initials: L
authors.lastname: Hee
authors.affiliation: South Western Sydney Clinical School, The University of NSW, Sydney, New South Wales, Australia; Radiology Department, Liverpool Hospital, Sydney, New South Wales, Australia.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Moses
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, New South Wales, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, New South Wales, Australia.
authors.forename: James
authors.initials: J
authors.lastname: Otton
authors.affiliation: Radiology Department, Liverpool Hospital, Sydney, New South Wales, Australia.
authors.forename: Owen D
authors.initials: OD
authors.lastname: Terreblanche
authors.affiliation: South Western Sydney Clinical School, The University of NSW, Sydney, New South Wales, Australia.
authors.forename: Jessica
authors.initials: J
authors.lastname: Xiong
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, New South Wales, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, New South Wales, Australia; School of Medicine, University of Western Sydney, Campbelltown, New South Wales, Australia.
authors.forename: Upul
authors.initials: U
authors.lastname: Premawardhana
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, New South Wales, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, New South Wales, Australia; School of Medicine, University of Western Sydney, Campbelltown, New South Wales, Australia.
authors.forename: Rohan
authors.initials: R
authors.lastname: Rajaratnam
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, New South Wales, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, New South Wales, Australia.
authors.forename: Craig P
authors.initials: CP
authors.lastname: Juergens
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, New South Wales, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, New South Wales, Australia.
authors.forename: Hany R
authors.initials: HR
authors.lastname: Dimitri
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, New South Wales, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, New South Wales, Australia.
authors.forename: John K
authors.initials: JK
authors.lastname: French
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, New South Wales, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, New South Wales, Australia.
authors.forename: David A B
authors.initials: DA
authors.lastname: Richards
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, New South Wales, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, New South Wales, Australia.
authors.forename: Liza
authors.initials: L
authors.lastname: Thomas
mesh_terms: D002921:Cicatrix / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D015425:Myocardial Reperfusion; D011184:Postoperative Period; D011379:Prognosis; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D020107:Troponin T / Q000097:blood*; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D020107:Troponin T