title: High-sensitivity cardiac troponin T in stable patients undergoing pharmacological stress testing.
abstract: BACKGROUND
  Acute changes in high-sensitivity troponin T (hs-TnT) are induced by myocardial ischemia during exercise stress testing, but there are no reports of pharmacological stress testing.
  
  
  OBJECTIVE
  The pattern of troponin release by myocardial ischemia-induced pharmacological stress testing differs according to the ischemic burden in stable patients.
  
  
  METHODS
  In total, 250 patients with suspected coronary artery disease underwent pharmacological stress magnetic resonance imaging (MRI). The amount and degree of myocardial ischemia on MRI and ischemic outcomes at 6 months were determined. hs-TnT levels were measured at baseline and 1 and 3 hours after testing. The 6-month clinical outcome was prespecified.
  
  
  RESULTS
  Fifty-one patients had moderate to severe myocardial ischemia (group A), and 199 patients had no or mild myocardial ischemia (group B). hs-TnT levels were significantly higher in group A than B at baseline (11 vs 8 pg/mL, P = 0.016) and at 1 hour (12 vs 8 pg/mL, P = 0.009) and 3 hours after testing (12 vs 9 pg/mL, P = 0.012). Baseline hs-TnT levels of ≥14 pg/mL showed a 43% sensitivity and 77% specificity in predicting moderate to severe ischemia by MRI (P = 0.03; area under the curve: 0.608, P = 0.017). Patients administered dobutamine had a higher acute change in hs-TnT levels 3 hours after testing than did those administered adenosine (21 vs 0 pg/mL, P < 0.001). There was a trend toward a higher incidence of myocardial infarction in patients with baseline hs-TnT levels of ≥14 pg/mL.
  
  
  CONCLUSIONS
  hs-TnT levels are significantly higher in patients with moderate to severe than no or mild myocardial ischemia.
authors.affiliation: Division of Cardiology, Department of Medicine, Faculty of Medicine Siriraj hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Nattawut
authors.initials: N
authors.lastname: Wongpraparut
authors.affiliation: Department of Clinical Pathology, Faculty of Medicine Siriraj hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Sudarat
authors.initials: S
authors.lastname: Piyophirapong
authors.affiliation: Division of Cardiology, Department of Medicine, Faculty of Medicine Siriraj hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Adisak
authors.initials: A
authors.lastname: Maneesai
authors.affiliation: Department of Clinical Pathology, Faculty of Medicine Siriraj hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Kosit
authors.initials: K
authors.lastname: Sribhen
authors.affiliation: Division of Cardiology, Department of Medicine, Faculty of Medicine Siriraj hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Rungroj
authors.initials: R
authors.lastname: Krittayaphong
authors.affiliation: Her Majesty Cardiac Center, Faculty of Medicine Siriraj hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Rungtiwa
authors.initials: R
authors.lastname: Pongakasira
authors.affiliation: Green Lane Cardiovascular Service, Auckland City Hospital, Auckland, New Zealand.
authors.forename: Harvey D
authors.initials: HD
authors.lastname: White
mesh_terms: D000241:Adenosine / Q000008:administration & dosage; D058665:Adrenergic beta-1 Receptor Agonists / Q000008:administration & dosage; D000368:Aged; D015331:Cohort Studies; D004280:Dobutamine / Q000008:administration & dosage; D005080:Exercise Test; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000097:blood / Q000175:diagnosis*; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D020107:Troponin T / Q000097:blood*; D014665:Vasodilator Agents / Q000008:administration & dosage
chemical_list: D058665:Adrenergic beta-1 Receptor Agonists; D020107:Troponin T; D014665:Vasodilator Agents; D004280:Dobutamine; D000241:Adenosine