title: Pre-angioplasty instantaneous wave-free ratio pullback provides virtual intervention and predicts hemodynamic outcome for serial lesions and diffuse coronary artery disease.
abstract: OBJECTIVE
  The aim of this study was to perform hemodynamic mapping of the entire vessel using motorized pullback of a pressure guidewire with continuous instantaneous wave-free ratio (iFR) measurement.
  
  
  BACKGROUND
  Serial stenoses or diffuse vessel narrowing hamper pressure wire-guided management of coronary stenoses. Characterization of functional relevance of individual stenoses or narrowed segments constitutes an unmet need in ischemia-driven percutaneous revascularization.
  
  
  METHODS
  The study was performed in 32 coronary arteries with tandem and/or diffusely diseased vessels. An automated iFR physiological map, integrating pullback speed and physiological information, was built using dedicated software to calculate physiological stenosis severity, length, and intensity (ΔiFR/mm). This map was used to predict the best-case post-percutaneous coronary intervention (PCI) iFR (iFRexp) according to the stented location, and this was compared with the observed iFR post-PCI (iFRobs).
  
  
  RESULTS
  After successful PCI, the mean difference between iFRexp and iFRobs was small (mean difference: 0.016 ± 0.004) with a strong relationship between ΔiFRexp and ΔiFRobs (r = 0.97, p < 0.001). By identifying differing iFR intensities, it was possible to identify functional stenosis length and quantify the contribution of each individual stenosis or narrowed segment to overall vessel stenotic burden. Physiological lesion length was shorter than anatomic length (12.6 ± 1.5 vs. 23.3 ± 1.3, p < 0.001), and targeting regions with the highest iFR intensity predicted significant improvement post-PCI (r = 0.86, p < 0.001).
  
  
  CONCLUSIONS
  iFR measurements during continuous resting pressure wire pullback provide a physiological map of the entire coronary vessel. Before a PCI, the iFR pullback can predict the hemodynamic consequences of stenting specific stenoses and thereby may facilitate the intervention and stenting strategy.
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Sukhjinder S
authors.initials: SS
authors.lastname: Nijjer
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Sayan
authors.initials: S
authors.lastname: Sen
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Petraco
authors.affiliation: Cardiovascular Institute, Hospital Clínico San Carlos, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Escaned
authors.affiliation: Cardiovascular Institute, Hospital Clínico San Carlos, Madrid, Spain.
authors.forename: Mauro
authors.initials: M
authors.lastname: Echavarria-Pinto
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Christopher
authors.initials: C
authors.lastname: Broyd
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Rasha
authors.initials: R
authors.lastname: Al-Lamee
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Foin
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Rodney A
authors.initials: RA
authors.lastname: Foale
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Iqbal S
authors.initials: IS
authors.lastname: Malik
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Ghada W
authors.initials: GW
authors.lastname: Mikhail
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Amarjit S
authors.initials: AS
authors.lastname: Sethi
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Mahmud
authors.initials: M
authors.lastname: Al-Bustami
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Raffi R
authors.initials: RR
authors.lastname: Kaprielian
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Masood A
authors.initials: MA
authors.lastname: Khan
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Baker
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Bellamy
authors.affiliation: Institute of Cardiovascular Science, University College London, London, United Kingdom.
authors.forename: Alun D
authors.initials: AD
authors.lastname: Hughes
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Jamil
authors.initials: J
authors.lastname: Mayet
authors.affiliation: Imperial College London, London, United Kingdom.
authors.forename: Darrel P
authors.initials: DP
authors.lastname: Francis
authors.affiliation: National Institute for Health Research (NIHR) Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Imperial College, London, United Kingdom.
authors.forename: Carlo
authors.initials: C
authors.lastname: Di Mario
authors.affiliation: Imperial College London, London, United Kingdom. Electronic address: justin.davies@imperial.ac.uk.
authors.forename: Justin E R
authors.initials: JE
authors.lastname: Davies
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000295:instrumentation; D062186:Arterial Pressure; D006328:Cardiac Catheterization / Q000295:instrumentation / Q000379:methods*; D062906:Cardiac Catheters; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy*; D003326:Coronary Circulation; D023921:Coronary Stenosis / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy*; D003331:Coronary Vessels / Q000503:physiopathology*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D012815:Signal Processing, Computer-Assisted; D012984:Software; D015607:Stents; D016896:Treatment Outcome
keywords: coronary physiology; instantaneous wave-free ratio; percutaneous coronary intervention; pressure wire