title: Coronary thermodilution to assess flow reserve: validation in humans.
abstract: BACKGROUND
  Guide wire-based simultaneous measurement of fractional flow reserve (FFR) and coronary flow reserve (CFR) is important to understand microvascular disease of the heart. The aim of this study was to investigate the feasibility of simultaneous measurement of FFR and CFR by one pressure-temperature sensor-tipped guide wire with the use of coronary thermodilution and to compare CFR by thermodilution (CFR(thermo)) with simultaneously measured Doppler CFR (CFR(Doppl)).
  
  
  RESULTS
  In 103 coronary arteries in 50 patients, a pressure-temperature sensor-tipped 0.014-inch floppy guide wire and a 0.014-inch Doppler guide wire were introduced. Both normal vessels and a wide range of stenotic vessels were included. With 3 mL of saline at room temperature used as an indicator, by hand-injection, thermodilution curves in the coronary artery were obtained in triplicate, both at baseline and at intravenous adenosine-induced maximum hyperemia. After adequate curve-fitting, CFR(thermo) was calculated from the ratio of inverse mean transit times and compared with CFR(Doppl) calculated by velocities at hyperemia and baseline. Adequate sets of thermodilution curves and corresponding CFR(thermo) could be obtained in 87% of the arteries versus 91% for Doppler CFR and 100% for FFR. CFR(thermo) correlated fairly well to CFR(Doppl) (CFR(thermo)=0.84 CFR(Doppl)+0.17; r=0.80; P<0.001), although individual differences of >20% between both indexes were seen in a quarter of all arteries.
  
  
  CONCLUSIONS
  This study shows the feasibility of simultaneous measurement of FFR (by coronary pressure) and CFR (by coronary thermodilution) in humans by one single guide wire in a practical and straightforward way and will facilitate assessment of microvascular disease.
authors.affiliation: Department of Cardiology, Catharina Hospital, Eindhoven, the Netherlands. nico.pijls@inter.nl.net
authors.forename: Nico H J
authors.initials: NH
authors.lastname: Pijls
authors.forename: Bernard
authors.initials: B
authors.lastname: De Bruyne
authors.forename: Leif
authors.initials: L
authors.lastname: Smith
authors.forename: Wilbert
authors.initials: W
authors.lastname: Aarnoudse
authors.forename: Emanuele
authors.initials: E
authors.lastname: Barbato
authors.forename: Jozef
authors.initials: J
authors.lastname: Bartunek
authors.forename: G Jan Willem
authors.initials: GJ
authors.lastname: Bech
authors.forename: Frans
authors.initials: F
authors.lastname: Van De Vosse
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D001831:Body Temperature; D006328:Cardiac Catheterization / Q000295:instrumentation / Q000379:methods; D003326:Coronary Circulation / Q000502:physiology*; D023921:Coronary Stenosis / Q000175:diagnosis / Q000503:physiopathology; D003331:Coronary Vessels / Q000502:physiology*; D017097:Electric Impedance; D004562:Electrocardiography; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D008833:Microcirculation / Q000502:physiology; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013815:Thermodilution / Q000379:methods