title: Comparison between non-invasive coronary flow reserve and fractional flow reserve to assess the functional significance of left anterior descending artery stenosis of intermediate severity.
abstract: BACKGROUND
  Assessment of the functional significance of left anterior descending coronary artery (LAD) stenosis of intermediate severity (50%-70% diameter stenosis) is challenging. The aim of this study was to compare the value of noninvasive coronary flow reserve (CFR) with that of invasive fractional flow reserve (FFR) in the setting of LAD stenosis of angiographic intermediate severity.
  
  
  METHODS
  Fifty stable consecutive patients (mean age, 63 ± 13 years; 11 women; mean left ventricular ejection fraction, 61 ± 10%) with angiographic proximal LAD stenoses of intermediate severity (55.5 ± 5% diameter stenosis on quantitative coronary angiography), no previous anterior myocardial infarction, and various vascular risk factors were prospectively studied. They underwent FFR assessment with intracoronary bolus adenosine (150 μg), and CFR assessment using intravenous adenosine (140 μg/kg/min over 2 min) in the distal part of the LAD on the same day in nearly all patients. CFR was defined as hyperemic peak diastolic LAD flow velocity divided by baseline flow velocity (normal value >2), and FFR was defined as distal pressure divided by mean aortic pressure during maximal hyperemia (normal value >0.8).
  
  
  RESULTS
  The mean FFR and CFR were 0.84 ± 0.07 and 2.7 ± 0.75, respectively, in the whole population. Concordant results between FFR and CFR were seen in 44 patients (88%) and discordant results in six patients (12%). There was a significant correlation between CFR and FFR (r = 0.59, P < .01). A better correlation was found between FFR and percentage LAD diameter stenosis, and lesion length (all P values < .05), than between CFR and the same anatomic markers of stenosis severity (all P values = NS). The sensitivity, specificity, and positive and negative predictive values of CFR >2 to detect a nonsignificant lesion defined by normal FFR were 95%, 69%, 90%, and 82%, respectively.
  
  
  CONCLUSIONS
  In patients with LAD stenosis of intermediate severity, discordant results between noninvasive CFR and FFR were not unusual, and the anatomic determinants of the stenosis were better correlated to FFR than to CFR. However, CFR, which is a global evaluation of the coronary tree, has very high sensitivity to detect a nonsignificant lesion, despite the high prevalence of vascular risk factors.
authors.affiliation: Department of Cardiology and Intensive Care Unit, Compiègne Hospital, Compiègne, France. patrickmeimoun@free.fr
authors.forename: Patrick
authors.initials: P
authors.lastname: Meimoun
authors.forename: Smain
authors.initials: S
authors.lastname: Sayah
authors.forename: Anne
authors.initials: A
authors.lastname: Luycx-Bore
authors.forename: Jacques
authors.initials: J
authors.lastname: Boulanger
authors.forename: Frederic
authors.initials: F
authors.lastname: Elmkies
authors.forename: Tahar
authors.initials: T
authors.lastname: Benali
authors.forename: Hamdane
authors.initials: H
authors.lastname: Zemir
authors.forename: Luc
authors.initials: L
authors.lastname: Doutrelan
authors.forename: Jerome
authors.initials: J
authors.lastname: Clerc
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology*; D016009:Chi-Square Distribution; D017023:Coronary Angiography; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D015150:Echocardiography, Doppler / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index