title: Development and validation of a new adenosine-independent index of stenosis severity from coronary wave-intensity analysis: results of the ADVISE (ADenosine Vasodilator Independent Stenosis Evaluation) study.
abstract: OBJECTIVE
  The purpose of this study was to develop an adenosine-independent, pressure-derived index of coronary stenosis severity.
  
  
  BACKGROUND
  Assessment of stenosis severity with fractional flow reserve (FFR) requires that coronary resistance is stable and minimized. This is usually achieved by administration of pharmacological agents such as adenosine. In this 2-part study, we determine whether there is a time when resistance is naturally minimized at rest and assess the diagnostic efficiency, compared with FFR, of a new pressure-derived adenosine-free index of stenosis severity over that time.
  
  
  METHODS
  A total of 157 stenoses were assessed. In part 1 (39 stenoses), intracoronary pressure and flow velocity were measured distal to the stenosis; in part 2 (118 stenoses), intracoronary pressure alone was measured. Measurements were made at baseline and under pharmacologic vasodilation with adenosine.
  
  
  RESULTS
  Wave-intensity analysis identified a wave-free period in which intracoronary resistance at rest is similar in variability and magnitude (coefficient of variation: 0.08 ± 0.06 and 284 ± 147 mm Hg s/m) to those during FFR (coefficient of variation: 0.08 ± 0.06 and 302 ± 315 mm Hg s/m; p = NS for both). The resting distal-to-proximal pressure ratio during this period, the instantaneous wave-free ratio (iFR), correlated closely with FFR (r = 0.9, p < 0.001) with excellent diagnostic efficiency (receiver-operating characteristic area under the curve of 93%, at FFR <0.8), specificity, sensitivity, negative and positive predictive values of 91%, 85%, 85%, and 91%, respectively.
  
  
  CONCLUSIONS
  Intracoronary resistance is naturally constant and minimized during the wave-free period. The instantaneous wave-free ratio calculated over this period produces a drug-free index of stenosis severity comparable to FFR. (Vasodilator Free Measure of Fractional Flow Reserve [ADVISE]; NCT01118481).
authors.affiliation: International Centre for Circulatory Health, National Heart and Lung Institute, Imperial College London, London, UK. sayan.sen@imperial.ac.uk
authors.forename: Sayan
authors.initials: S
authors.lastname: Sen
authors.forename: Javier
authors.initials: J
authors.lastname: Escaned
authors.forename: Iqbal S
authors.initials: IS
authors.lastname: Malik
authors.forename: Ghada W
authors.initials: GW
authors.lastname: Mikhail
authors.forename: Rodney A
authors.initials: RA
authors.lastname: Foale
authors.forename: Rafael
authors.initials: R
authors.lastname: Mila
authors.forename: Jason
authors.initials: J
authors.lastname: Tarkin
authors.forename: Ricardo
authors.initials: R
authors.lastname: Petraco
authors.forename: Christopher
authors.initials: C
authors.lastname: Broyd
authors.forename: Richard
authors.initials: R
authors.lastname: Jabbour
authors.forename: Amarjit
authors.initials: A
authors.lastname: Sethi
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Baker
authors.forename: Micheal
authors.initials: M
authors.lastname: Bellamy
authors.forename: Mahmud
authors.initials: M
authors.lastname: Al-Bustami
authors.forename: David
authors.initials: D
authors.lastname: Hackett
authors.forename: Masood
authors.initials: M
authors.lastname: Khan
authors.forename: David
authors.initials: D
authors.lastname: Lefroy
authors.forename: Kim H
authors.initials: KH
authors.lastname: Parker
authors.forename: Alun D
authors.initials: AD
authors.lastname: Hughes
authors.forename: Darrel P
authors.initials: DP
authors.lastname: Francis
authors.forename: Carlo
authors.initials: C
authors.lastname: Di Mario
authors.forename: Jamil
authors.initials: J
authors.lastname: Mayet
authors.forename: Justin E
authors.initials: JE
authors.lastname: Davies
mesh_terms: D000241:Adenosine / Q000008:administration & dosage; D017023:Coronary Angiography / Q000379:methods*; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology*; D023921:Coronary Stenosis / Q000175:diagnosis* / Q000503:physiopathology; D003331:Coronary Vessels / Q000187:drug effects / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012039:Regional Blood Flow / Q000187:drug effects; D012720:Severity of Illness Index; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology*; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000008:administration & dosage
chemical_list: D014665:Vasodilator Agents; D000241:Adenosine