title: Diagnostic cutoff for pressure drop coefficient in relation to fractional flow reserve and coronary flow reserve: A patient-level analysis.
abstract: OBJECTIVE
  Functional assessment of intermediate coronary stenosis during cardiac catheterization is conducted using diagnostic parameters like fractional flow reserve (FFR), coronary flow reserve (CFR), hyperemic stenosis resistance index (HSR), and hyperemic microvascular resistance (HMR). CDP (ratio of pressure drop across a stenosis to distal dynamic pressure), a nondimensional index derived from fundamental fluid dynamic principles, based on a combination of intracoronary pressure, and flow measurements may improve the functional assessment of coronary lesion severity.
  
  
  METHODS
  Patient-level data pertaining to 350 intracoronary pressure and flow measurements across coronary stenoses was assessed to evaluate CFR, FFR, HSR, HMR, and CDP. CDP was calculated as (ΔP)/(0.5 × ρ × APV(2)). The density of blood (ρ) was assumed to be 1.05 g/cm(3). The correlation of current diagnostic parameters (CFR, FFR, HSR, and HMR) with CDP was evaluated. The receiver operating characteristic (ROC) curve was used to identify the optimal cut-off point of CDP, corresponding to the clinically used cut-off values (FFR = 0.80 and CFR = 2.0).
  
  
  RESULTS
  CDP correlated significantly with FFR (r = 0.81, P < 0.05) and had significant diagnostic efficiency (ROC-area under curve of 86%), specificity (72%) and sensitivity (85%) at FFR < 0.8. The corresponding cut-off value for CDP to detect FFR < 0.8 was at CDP>25.4. CDP also correlated significantly (r = 0.98, P < 0.05) with epicardial-specific parameter, HSR.
  
  
  CONCLUSIONS
  CDP, a functional parameter based on both intracoronary pressure and flow measurements, has close agreement (area under ROC curve = 86%) with FFR, the frequently used method of evaluating stenosis severity.
authors.affiliation: Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, Ohio.|Veteran Affairs Medical Center, Cincinnati, Ohio.
authors.forename: Kranthi K
authors.initials: KK
authors.lastname: Kolli
authors.affiliation: Department of Cardiology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Tim P
authors.initials: TP
authors.lastname: van de Hoef
authors.affiliation: Veteran Affairs Medical Center, Cincinnati, Ohio.|Division of Cardiovascular Disease, University of Cincinnati, Cincinnati, Ohio.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Effat
authors.affiliation: Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, Ohio.|Veteran Affairs Medical Center, Cincinnati, Ohio.
authors.forename: Rupak K
authors.initials: RK
authors.lastname: Banerjee
authors.affiliation: Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, Ohio.|Veteran Affairs Medical Center, Cincinnati, Ohio.
authors.forename: Srikara V
authors.initials: SV
authors.lastname: Peelukhana
authors.affiliation: Department of Environmental Health, University of Cincinnati, Cincinnati, Ohio.
authors.forename: Paul
authors.initials: P
authors.lastname: Succop
authors.affiliation: Division of Cardiovascular Disease, University of Alabama-Birmingham, Alabama.
authors.forename: Massoud A
authors.initials: MA
authors.lastname: Leesar
authors.affiliation: Veteran Affairs Medical Center, Cincinnati, Ohio.|Division of Cardiovascular Disease, University of Cincinnati, Cincinnati, Ohio.
authors.forename: Arif
authors.initials: A
authors.lastname: Imran
authors.affiliation: Department of Cardiology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Piek
authors.affiliation: Division of Cardiology, Saint Louis University School of Medicine, St. Louis, Missouri.
authors.forename: Tarek A
authors.initials: TA
authors.lastname: Helmy
mesh_terms: D000368:Aged; D019540:Area Under Curve; D062186:Arterial Pressure; D006328:Cardiac Catheterization; D017023:Coronary Angiography; D023921:Coronary Stenosis / Q000175:diagnosis* / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D012720:Severity of Illness Index
keywords: CFR; FFR; catheterization: patient-level data; coronary disease