title: Differences between automatically detected and steady-state fractional flow reserve.
abstract: BACKGROUND
  Measurement of fractional flow reserve (FFR) has become a standard diagnostic tool in the catheterization laboratory. FFR evaluation studies were based on pressure recordings during steady-state maximum hyperemia. Commercially available computer systems detect the lowest Pd/Pa ratio automatically, which might not always be measured during steady-state hyperemia. We sought to compare the automatically detected FFR and true steady-state FFR.
  
  
  RESULTS
  Pressure measurement traces of 105 coronary lesions from 77 patients with intermediate coronary lesions or multivessel disease were reviewed. In all patients, hyperemia had been achieved by intravenous adenosine administration using a dosage of 140 µg/kg/min. In 42 lesions (40%) automatically detected FFR was lower than true steady-state FFR. Mean bias was 0.009 (standard deviation 0.015, limits of agreement -0.02, 0.037). In 4 lesions (3.8%) both methods lead to different treatment recommendations, in all 4 cases instantaneous wave-free ratio confirmed steady-state FFR.
  
  
  CONCLUSIONS
  Automatically detected FFR was slightly lower than steady-state FFR in more than one-third of cases. Consequently, interpretation of automatically detected FFR values closely below the cutoff value requires special attention.
authors.affiliation: Klinik für Kardiologie, Klinikum Oldenburg gGmbH, European Medical School Oldenburg-Groningen, Carl von Ossietzky Universität Oldenburg, Rahel-Straus-Str. 10, 26133, Oldenburg, Germany. t.haerle@gmx.de.
authors.forename: Tobias
authors.initials: T
authors.lastname: Härle
authors.affiliation: Klinik für Kardiologie, Klinikum Oldenburg gGmbH, European Medical School Oldenburg-Groningen, Carl von Ossietzky Universität Oldenburg, Rahel-Straus-Str. 10, 26133, Oldenburg, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Meyer
authors.affiliation: Klinik für Kardiologie, Klinikum Oldenburg gGmbH, European Medical School Oldenburg-Groningen, Carl von Ossietzky Universität Oldenburg, Rahel-Straus-Str. 10, 26133, Oldenburg, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Vahldiek
authors.affiliation: Klinik für Kardiologie, Klinikum Oldenburg gGmbH, European Medical School Oldenburg-Groningen, Carl von Ossietzky Universität Oldenburg, Rahel-Straus-Str. 10, 26133, Oldenburg, Germany.
authors.forename: Albrecht
authors.initials: A
authors.lastname: Elsässer
mesh_terms: D000241:Adenosine / Q000008:administration & dosage*; D061605:Administration, Intravenous; D000368:Aged; D006328:Cardiac Catheterization / Q000379:methods*; D003324:Coronary Artery Disease / Q000175:diagnosis*; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D006940:Hyperemia / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
chemical_list: D000241:Adenosine
keywords: Adenosine; FFR; Hyperemia; Intracoronary pressure measurement; iFR