title: The instantaneous wave-free ratio (iFR) for evaluation of non-culprit lesions in patients with acute coronary syndrome and multivessel disease.
abstract: BACKGROUND
  Adenosine administration is currently required for evaluation of stenosis severity with fractional flow reserve (FFR). The instantaneous wave-free ratio (iFR) was recently introduced as an adenosine-free alternative in patients with stable CAD. The aim of the present study was to replicate the findings of previous iFR studies using an independent calculation algorithm and to evaluate the iFR for the assessment of non-culprit vessels in patients with acute coronary syndrome (ACS).
  
  
  RESULTS
  53 patients with ACS (65%) and at least one non-culprit intermediate lesion and 29 (35%) with stable CAD were included. A total of 123 stenoses were evaluated with both FFR and iFR. Classification match of iFR in ACS was not inferior to stable CAD (79.5% in ACS and 84.4% in CAD; p=0.497). Accordingly, no difference was observed in iFR/FFR correlation between ACS and stable CAD (r=0.66 in ACS vs. r=0.69 in CAD). Overall, a significant correlation was found between iFR and FFR (r=0.68; p<0.001) with a good diagnostic efficiency at ROC analysis (area under the curve: 0.87). In addition, neither the localization of the stenosis within the coronary tree (p=0.147) nor the time interval from the acute event (p=0.550) significantly influenced the concordance of iFR with FFR.
  
  
  CONCLUSIONS
  The iFR is a promising method for the assessment of non-culprit lesion severity in patients with acute coronary syndrome.
authors.affiliation: Division of Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy; URT-CNR, Magna Graecia University, Catanzaro, Italy. Electronic address: indolfi@unicz.it.
authors.forename: Ciro
authors.initials: C
authors.lastname: Indolfi
authors.affiliation: Division of Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Mongiardo
authors.affiliation: Division of Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy.
authors.forename: Carmen
authors.initials: C
authors.lastname: Spaccarotella
authors.affiliation: Division of Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Torella
authors.affiliation: Division of Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Caiazzo
authors.affiliation: Division of Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Polimeni
authors.affiliation: Division of Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy.
authors.forename: Sabato
authors.initials: S
authors.lastname: Sorrentino
authors.affiliation: Division of Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy.
authors.forename: Mariella
authors.initials: M
authors.lastname: Micieli
authors.affiliation: Division of Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy.
authors.forename: Jolanda
authors.initials: J
authors.lastname: Sabatino
authors.affiliation: Division of Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Curcio
authors.affiliation: Division of Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: De Rosa
mesh_terms: D054058:Acute Coronary Syndrome / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D000368:Aged; D017023:Coronary Angiography / Q000379:methods; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D005260:Female; D053805:Fractional Flow Reserve, Myocardial / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged
keywords: Acute coronary syndromes (ACS); Coronary stenosis; Fractional flow reserve (FFR); Instantaneous wave-free ratio (iFR)