title: Association between Cardiac Troponin Level and Coronary Flow Reserve in Patients without Coronary Artery Disease: Insight from a Thermodilution Technique Using an Intracoronary Pressure Wire.
abstract: OBJECTIVE
  Cardiac troponins are associated with increased mortality, even among patients with no coronary artery disease. Elevated cardiac troponin levels are frequently observed in patients without significant coronary lesions, although the mechanism underlying this finding is unclear. The aim of our study was to evaluate the association between the levels of cardiac troponin and coronary flow reserve (CFR).
  
  
  METHODS
  We evaluated serum cardiac troponin-I in 19 patients (9 female; age 61.9±10.9 year-old). All patients had an ejection fraction >40% and angiographically normal coronary arteries. Simultaneous measurements of fractional flow reserve (FFR), the index of microcirculatory resistance (IMR), and CFR measurements using an intracoronary temperature- and pressure-sensing guidewire under basal conditions and during maximal hyperemia were performed in three vessels: the left anterior descending artery (LAD), left circumflex artery (LCX) and right coronary artery (RCA).
  
  
  RESULTS
  All patients were followed for a median of 13 months. FFR, IMR, and CFR measurements were performed successfully in all subjects. Mean CFRs of LAD, LCX, and RCA were 1.98±1.20, 2.75±2.11, and 4.44±2.51, respectively. Mean IMRs of LAD, LCX and RCA were 33.28±18.78, 29.11±26.70, and 30.55±23.65, respectively. There was a poor correlation between CFR and troponin-I values in each vessel. In selecting the lowest value of CFR in each patient as the corresponding value, the lowest CFR was not associated with troponin-I levels (r=-0.219, p=0.367).
  
  
  CONCLUSIONS
  In patients without significant coronary lesions, the correlation between CFR and troponin-I level was not significant using a thermodilution technique. Further study of a larger population with longer-term follow-up may be needed to more fully understand microvascular dysfunction.
authors.affiliation: Regional Cardiocerebrovascular Center, Dong-A University Hospital, Busan, Korea. ; Division of Cardiology, Department of Internal Medicine, Dong-A University College of Medicine, Busan, Korea.
authors.forename: Kyungil
authors.initials: K
authors.lastname: Park
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Dong-A University College of Medicine, Busan, Korea.
authors.forename: Minkwan
authors.initials: M
authors.lastname: Kim
authors.affiliation: Regional Cardiocerebrovascular Center, Dong-A University Hospital, Busan, Korea. ; Division of Cardiology, Department of Internal Medicine, Dong-A University College of Medicine, Busan, Korea.
authors.forename: Young-Rak
authors.initials: YR
authors.lastname: Cho
authors.affiliation: Regional Cardiocerebrovascular Center, Dong-A University Hospital, Busan, Korea. ; Division of Cardiology, Department of Internal Medicine, Dong-A University College of Medicine, Busan, Korea.
authors.forename: Jong-Sung
authors.initials: JS
authors.lastname: Park
authors.affiliation: Regional Cardiocerebrovascular Center, Dong-A University Hospital, Busan, Korea. ; Division of Cardiology, Department of Internal Medicine, Dong-A University College of Medicine, Busan, Korea.
authors.forename: Tea-Ho
authors.initials: TH
authors.lastname: Park
authors.affiliation: Regional Cardiocerebrovascular Center, Dong-A University Hospital, Busan, Korea. ; Division of Cardiology, Department of Internal Medicine, Dong-A University College of Medicine, Busan, Korea.
authors.forename: Moo Hyun
authors.initials: MH
authors.lastname: Kim
authors.affiliation: Regional Cardiocerebrovascular Center, Dong-A University Hospital, Busan, Korea. ; Division of Cardiology, Department of Internal Medicine, Dong-A University College of Medicine, Busan, Korea.
authors.forename: Young-Dae
authors.initials: YD
authors.lastname: Kim
keywords: Microvessels; Myocardiol coronary flow reserve; Troponin; Vascular resistance