title: Cardiac troponin changes to distinguish type 1 and type 2 myocardial infarction and 180-day mortality risk.
abstract: OBJECTIVE
  To determine the ability of serial cardiac troponin (cTnI) changes (delta) to distinguish type 1 and type 2 myocardial infarction (MI) (excluding all ST-segment elevation MIs (STEMIs)) and describe the diagnostic accuracy and 180-day mortality in MI versus no-MI patients.
  
  
  RESULTS
  Serial cTnIs were measured in 1112 consecutive patients without STEMI and within 6h of presentation to a United States emergency department: 856 (77%) with no MI, 66 (6%) type 1 MI, and 190 (17%) type 2 MI. Of the 0 to 3h and 0 to 6h absolute and relative cTnI changes, only the distribution of absolute change from 0 to 6h was significantly different between type 1 and type 2 MI: median (interquartile range) 311 (1430) ng/l vs. 80 (330) ng/l, p=0.03. Neither the absolute concentration change nor the absolute percent change from either 0 h to 3h (areas under the curves (AUCs) 0.57 and 0.54 respectively) or 0 h to 6h (AUCs 0.60 and 0.51) improved on the performance of the individual cTnI results at 3h (AUC 0.60) or 6h (AUC 0.62), respectively. After adjusting for age, and histories of heart failure and renal insufficiency, those with type 2 MI (hazard ratio 2.9, 95% confidence interval (CI) 1.4-5.9, p=0.004) and those with no index MI and cTnI(max0-6h) > 34 ng/l (2.5, CI 1.1-6.0, p=0.04) had increased risk of death within 180 days compared with those with no MI and cTnI(max 0-6h) ≤ 34 ng/l.
  
  
  CONCLUSIONS
  Delta cTnI did not aid in distinguishing type 1 MI from the more common type 2 MI. Patients diagnosed with type 2 MIs, which represented more than half of all index MIs, had increased risk of death after discharge.
authors: Division of Cardiology, Department of Medicine, Hennepin County Medical Center, Minneapolis, USA.
authors: Yader
authors: Y
authors: Sandoval
authors: Division of Cardiology, Department of Medicine, Hennepin County Medical Center, Minneapolis, USA.
authors: Sarah E
authors: SE
authors: Thordsen
authors: Department of Emergency Medicine, Hennepin County Medical Center, Minneapolis, USA.
authors: Stephen W
authors: SW
authors: Smith
authors: Cardiac Biomarkers Trials Laboratory, Minneapolis Medical Research Foundation, Hennepin County Medical Center, Minneapolis, USA.
authors: Karen M
authors: KM
authors: Schulz
authors: Cardiac Biomarkers Trials Laboratory, Minneapolis Medical Research Foundation, Hennepin County Medical Center, Minneapolis, USA.
authors: MaryAnn M
authors: MM
authors: Murakami
authors: Biostatistics Consultant, Minot, USA.
authors: Lesly A
authors: LA
authors: Pearce
authors: Cardiac Biomarkers Trials Laboratory, Minneapolis Medical Research Foundation, Hennepin County Medical Center, Minneapolis, USA Department of Laboratory Medicine and Pathology, Hennepin County Medical Center and University of Minnesota, Minneapolis, USA apple004@umn.edu.
authors: Fred S
authors: FS
authors: Apple
mesh_terms: D003937:Diagnosis, Differential; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000401:mortality; D012372:ROC Curve; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D016019:Survival Analysis; D019209:Troponin C / Q000378:metabolism*
chemical_list: D019209:Troponin C
keywords: Myocardial infarction; cardiac troponin; delta troponin; risk outcomes; type 2 MI; universal definition