title: Hybrid iFR-FFR decision-making strategy: implications for enhancing universal adoption of physiology-guided coronary revascularisation.
abstract: OBJECTIVE
  Adoption of fractional flow reserve (FFR) remains low (6-8%), partly because of the time, cost and potential inconvenience associated with vasodilator administration. The instantaneous wave-Free Ratio (iFR) is a pressure-only index of stenosis severity calculated without vasodilator drugs. Before outcome trials test iFR as a sole guide to revascularisation, we evaluate the merits of a hybrid iFR-FFR decision-making strategy for universal physiological assessment.
  
  
  RESULTS
  Coronary pressure traces from 577 stenoses were analysed. iFR was calculated as the ratio between Pd and Pa in the resting diastolic wave-free window. A hybrid iFR-FFR strategy was evaluated, by allowing iFR to defer some stenoses (where negative predictive value is high) and treat others (where positive predictive value is high), with adenosine being given only to patients with iFR in between those values. For the most recent fixed FFR cut-off (0.8), an iFR of <0.86 could be used to confirm treatment (PPV of 92%), whilst an iFR value of >0.93 could be used to defer revascularisation (NPV of 91%). Limiting vasodilator drugs to cases with iFR values between 0.86 to 0.93 would obviate the need for vasodilator drugs in 57% of patients, whilst maintaining 95% agreement with an FFR-only strategy. If the 0.75-0.8 FFR grey zone is accounted for, vasodilator drug requirement would decrease by 76%.
  
  
  CONCLUSIONS
  A hybrid iFR-FFR decision-making strategy for revascularisation could increase adoption of physiology-guided PCI, by more than halving the need for vasodilator administration, whilst maintaining high classification agreement with an FFR-only strategy.
authors.affiliation: International Centre for Circulatory Health, National Heart and Lung Institute, Imperial College London and Imperial College Healthcare NHS Trust, London, United Kingdom. rpetraco@imperial.ac.uk
authors.forename: Ricardo
authors.initials: R
authors.lastname: Petraco
authors.forename: Jin Joo
authors.initials: JJ
authors.lastname: Park
authors.forename: Sayan
authors.initials: S
authors.lastname: Sen
authors.forename: Sukhjinder S
authors.initials: SS
authors.lastname: Nijjer
authors.forename: Iqbal S
authors.initials: IS
authors.lastname: Malik
authors.forename: Mauro
authors.initials: M
authors.lastname: Echavarría-Pinto
authors.forename: Kaleab N
authors.initials: KN
authors.lastname: Asrress
authors.forename: Chang-Wook
authors.initials: CW
authors.lastname: Nam
authors.forename: Enrico
authors.initials: E
authors.lastname: Macías
authors.forename: Rodney A
authors.initials: RA
authors.lastname: Foale
authors.forename: Amarjit
authors.initials: A
authors.lastname: Sethi
authors.forename: Ghada W
authors.initials: GW
authors.lastname: Mikhail
authors.forename: Raffi
authors.initials: R
authors.lastname: Kaprielian
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Baker
authors.forename: David
authors.initials: D
authors.lastname: Lefroy
authors.forename: Michael
authors.initials: M
authors.lastname: Bellamy
authors.forename: Mahmud
authors.initials: M
authors.lastname: Al-Bustami
authors.forename: Masood A
authors.initials: MA
authors.lastname: Khan
authors.forename: Nieves
authors.initials: N
authors.lastname: Gonzalo
authors.forename: Alun D
authors.initials: AD
authors.lastname: Hughes
authors.forename: Darrel P
authors.initials: DP
authors.lastname: Francis
authors.forename: Jamil
authors.initials: J
authors.lastname: Mayet
authors.forename: Carlo
authors.initials: C
authors.lastname: Di Mario
authors.forename: Simon
authors.initials: S
authors.lastname: Redwood
authors.forename: Javier
authors.initials: J
authors.lastname: Escaned
authors.forename: Bon-Kwon
authors.initials: BK
authors.lastname: Koo
authors.forename: Justin E
authors.initials: JE
authors.lastname: Davies
mesh_terms: D000241:Adenosine / Q000627:therapeutic use; D000368:Aged; D003657:Decision Making; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009204:Myocardial Revascularization; D062645:Percutaneous Coronary Intervention
chemical_list: D000241:Adenosine