title: Intravascular ultrasound lumen area parameters for assessment of physiological ischemia by fractional flow reserve in intermediate coronary artery stenosis.
abstract: BACKGROUND
  A fractional flow reserve (FFR) of <0.8 is currently used to guide revascularization in lesions with intermediate coronary stenosis. Whether there is an intravascular ultrasound (IVUS) measurement or a cutoff value that can reliably determine which of these intermediate lesions requires intervention is unclear.
  
  
  OBJECTIVE
  We assessed IVUS measurement accuracy in defining functional ischemia by FFR.
  
  
  METHODS
  The analysis included 205 intermediate lesions (185 patients) located in vessel diameters >2.5 mm. Positive FFR was considered present at <0.8. IVUS measurements were correlated to the FFR findings in intermediate lesions with 40%-70% stenosis. Fifty-four (26.3%) lesions had FFR<0.8.
  
  
  RESULTS
  There was moderate correlation between FFR and IVUS measurements, including minimum lumen area (MLA) (r=0.36, P<.001), minimum lumen diameter (MLD) (r=0.25, P=<.001), lesion length (r=-0.43, P<.001), and area stenosis (r=-0.33, P=.01). A receiver operating characteristic curve (ROC) identified MLA<3.09 mm(2) (sensitivity 69.2%, specificity 79.5%) as the best threshold value for FFR<0.8. The correlation between FFR and IVUS was better for large vessels compared to small vessels. ROC analysis identified the best threshold value for FFR<0.8 of MLA<2.4 mm(2) [area under curve (AUC)=0.74] in lesions with reference vessel diameters of 2.5-3 mm, MLA<2.7 mm(2) (AUC=0.77) in lesions with reference vessel diameters of 3-3.5 mm, and MLA<3.6 mm(2) (AUC=0.70) in lesions with reference vessel diameters >3.5 mm.
  
  
  CONCLUSIONS
  Anatomic measurements of intermediate coronary lesions obtained by IVUS show a moderate correlation to FFR values. The correlation was better for larger-diameter vessels. Vessel size should always be taken into account when determining the MLA associated with functional ischemia.
authors.affiliation: Division of Cardiology, Washington Hospital Center, Washington, DC 20010, USA.
authors.forename: Itsik
authors.initials: I
authors.lastname: Ben-Dor
authors.forename: Rebecca
authors.initials: R
authors.lastname: Torguson
authors.forename: Teshome
authors.initials: T
authors.lastname: Deksissa
authors.forename: Anh B
authors.initials: AB
authors.lastname: Bui
authors.forename: Zhenyi
authors.initials: Z
authors.lastname: Xue
authors.forename: Lowell F
authors.initials: LF
authors.lastname: Satler
authors.forename: Augusto D
authors.initials: AD
authors.lastname: Pichard
authors.forename: Ron
authors.initials: R
authors.lastname: Waksman
mesh_terms: D000368:Aged; D006328:Cardiac Catheterization; D016009:Chi-Square Distribution; D017023:Coronary Angiography; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004219:District of Columbia; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D012042:Registries; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018084:Ultrasonography, Interventional