title: Instantaneous Wave-Free Ratio versus Fractional Flow Reserve guided intervention (iFR-SWEDEHEART): Rationale and design of a multicenter, prospective, registry-based randomized clinical trial.
abstract: BACKGROUND
  Instantaneous wave-free ratio (iFR) is a new hemodynamic resting index for assessment of coronary artery stenosis severity. iFR uses high frequency sampling to calculate a gradient across a coronary lesion during a period of diastole. The index has been tested against fractional flow reserve (FFR) and found to have an overall classification agreement of 80% to 85%. Whether the level of disagreement is clinically relevant is unknown. Clinical outcome data on iFR are scarce. This study is a registry-based randomized clinical trial, which is a novel strategy using health quality registries as on-line platforms for randomization, case record forms, and follow-up.
  
  
  METHODS
  iFR-SWEDEHEART is a multicenter, prospective, randomized, controlled, clinical open-label clinical trial. Two thousand patients with stable angina or acute coronary syndrome and an indication for physiology-guided assessment of one or more coronary stenoses will be randomized 1:1 to either iFR- or FFR-guided intervention. The randomization will be conducted online in the Swedish web-based system for enhancement and development of evidence-based care in heart disease evaluated according to recommended therapies (SWEDEHEART) registry. The trial has a non-inferiority design, with a primary combined end point of all-cause death, non-fatal myocardial infarction, and unplanned revascularization at 12 months. End points will be identified through national registries and undergo central blind adjudication to ensure data quality.
  
  
  CONCLUSIONS
  The iFR-SWEDEHEART trial is an registry-based randomized clinical trial evaluating the safety and efficacy of the diagnostic method iFR compared to FFR.
authors.affiliation: Department of Cardiology, Lund University, Skåne University Hospital, Lund, Sweden. Electronic address: matthias.gotberg@med.lu.se.
authors.forename: Matthias
authors.initials: M
authors.lastname: Götberg
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Skejby, Denmark.
authors.forename: Evald H
authors.initials: EH
authors.lastname: Christiansen
authors.affiliation: Department of Cardiology, Reykjavik University Hospital, Reykjavik, Iceland.
authors.forename: Ingibjörg
authors.initials: I
authors.lastname: Gudmundsdottir
authors.affiliation: Department of Radiology, Helsingborg County Hospital, Helsingborg, Sweden.
authors.forename: Lennart
authors.initials: L
authors.lastname: Sandhall
authors.affiliation: Department of Cardiology, Sahlgrenska University, Gothenburg, Sweden.
authors.forename: Elmir
authors.initials: E
authors.lastname: Omerovic
authors.affiliation: Department of Medical Sciences, Cardiology, and Uppsala Clinical Research Center, Uppsala University, Uppsala, Sweden.
authors.forename: Stefan K
authors.initials: SK
authors.lastname: James
authors.affiliation: Department of Cardiology, Lund University, Skåne University Hospital, Lund, Sweden.
authors.forename: David
authors.initials: D
authors.lastname: Erlinge
authors.affiliation: Örebro University, Faculty of Health, Department of Cardiology, Örebro, Sweden.
authors.forename: Ole
authors.initials: O
authors.lastname: Fröbert
mesh_terms: D054058:Acute Coronary Syndrome / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D000368:Aged; D017023:Coronary Angiography; D005260:Female; D005500:Follow-Up Studies; D053805:Fractional Flow Reserve, Myocardial / Q000502:physiology*; D006801:Humans; D008297:Male; D062645:Percutaneous Coronary Intervention / Q000379:methods*; D011446:Prospective Studies; D012372:ROC Curve; D012042:Registries; D012720:Severity of Illness Index; D016896:Treatment Outcome