title: Diagnostic performance of pressure drop coefficient in relation to fractional flow reserve and coronary flow reserve.
abstract: OBJECTIVE
  Functional assessment of coronary lesion severity during cardiac catheterization is conducted using diagnostic parameters like fractional flow reserve (FFR; pressure derived) and coronary flow reserve (CFR; flow derived). However, the complex hemodynamics of stenosis might not be sufficiently explained by either pressure or flow alone, particularly in the case of intermediate stenosis. CDP (ratio of pressure drop across a stenosis to distal dynamic pressure), a non-dimensional index derived from fundamental fluid dynamic principles based on a combination of intracoronary pressure and flow, may improve the functional assessment of coronary lesion severity.
  
  
  METHODS
  We performed a meta-analysis of seven studies, retrieved from MEDLINE and PubMed, comparing the results of FFR and CFR of the same lesions. Two studies reported functional measurements (pressure and flow) obtained in individual patients. Five studies reported two-dimensional plots of FFR vs. CFR. The FFR and CFR data were digitized and corresponding functional measurements were extracted using the reported mean values of hemodynamic data from each of the five studies. The receiver operating characteristic (ROC) curve was used to identify the optimal cut-off point of CDP, which corresponds to the clinically used cut-off values (FFR = 0.80, FFR = 0.75, and CFR = 2.0).
  
  
  RESULTS
  CDP correlated significantly with FFR (r = 0.78; P<.001) and had significant diagnostic efficiency (area under the ROC curve = 89%), specificity (83% and 85%), and sensitivity (81% and 76%) at FFR <0.8 and FFR <0.75, respectively. The corresponding cut-off value for CDP to detect FFR <0.80 and FFR <0.75 was at CDP >27.1 and CDP >27.9, respectively.
  
  
  CONCLUSIONS
  CDP, a functional parameter based on both intracoronary pressure and flow measurements, has close agreement (area under the ROC curve = 89%) with FFR, the most frequently used method for evaluation of coronary stenosis severity.
authors.affiliation: Department of Mechanical and Materials Engineering, 598 Rhodes Hall, PO Box 210072, Cincinnati, OH 45221-0072 USA. Rupak.Banerjee@UC.edu.
authors.forename: Kranthi K
authors.initials: KK
authors.lastname: Kolli
authors.forename: Imran
authors.initials: I
authors.lastname: Arif
authors.forename: Srikara V
authors.initials: SV
authors.lastname: Peelukhana
authors.forename: Paul
authors.initials: P
authors.lastname: Succop
authors.forename: Lloyd H
authors.initials: LH
authors.lastname: Back
authors.forename: Tarek A
authors.initials: TA
authors.lastname: Helmy
authors.forename: Massoud A
authors.initials: MA
authors.lastname: Leesar
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Effat
authors.forename: Rupak K
authors.initials: RK
authors.lastname: Banerjee
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000502:physiology*; D003326:Coronary Circulation / Q000502:physiology*; D023921:Coronary Stenosis / Q000175:diagnosis* / Q000503:physiopathology; D003331:Coronary Vessels / Q000503:physiopathology*; D005260:Female; D053805:Fractional Flow Reserve, Myocardial / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index