title: Clinical outcomes of combined flow-pressure drop measurements using newly developed diagnostic endpoint: Pressure drop coefficient in patients with coronary artery dysfunction.
abstract: OBJECTIVE
  To combine pressure and flow parameter, pressure drop coefficient (CDP) will result in better clinical outcomes in comparison to the fractional flow reserve (FFR) group.
  
  
  METHODS
  To test this hypothesis, a comparison was made between the FFR < 0.75 and CDP > 27.9 groups in this study, for the major adverse cardiac events [major adverse cardiac events (MACE): Primary outcome] and patients' quality of life (secondary outcome). Further, a comparison was also made between the survival curves for the FFR < 0.75 and CDP > 27.9 groups. Two-tailed χ (2) test proportions were performed for the comparison of primary and secondary outcomes. Kaplan-Meier survival analysis was performed to compare the survival curves of FFR < 0.75 and CDP > 27.9 groups (MedcalcV10.2, Mariakerke, Belgium). Results were considered statistically significant for P < 0.05.
  
  
  RESULTS
  The primary outcomes (%MACE) in the FFR < 0.75 group (20%, 4 out of 20) was not statistically different (P = 0.24) from the %MACE occurring in CDP > 27.9 group (8.57%, 2 out of 35). Noteworthy is the reduction in the %MACE in the CDP > 27.9 group, in comparison to the FFR < 0.75 group. Further, the secondary outcomes were not statistically significant between the FFR < 0.75 and CDP > 27.9 groups. Survival analysis results suggest that the survival time for the CDP > 27.9 group (n = 35) is significantly higher (P = 0.048) in comparison to the survival time for the FFR < 0.75 group (n = 20). The results remained similar for a FFR = 0.80 cut-off.
  
  
  CONCLUSIONS
  Based on the above, CDP could prove to be a better diagnostic end-point for clinical revascularization decision-making in the cardiac catheterization laboratories.
authors.affiliation: Mohamed A Effat, Division of Cardiovascular Health and Diseases, University of Cincinnati Medical Center, Veteran Affairs Medical Center, Cincinnati, OH 45221, United States.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Effat
authors.affiliation: Mohamed A Effat, Division of Cardiovascular Health and Diseases, University of Cincinnati Medical Center, Veteran Affairs Medical Center, Cincinnati, OH 45221, United States.
authors.forename: Srikara Viswanath
authors.initials: SV
authors.lastname: Peelukhana
authors.affiliation: Mohamed A Effat, Division of Cardiovascular Health and Diseases, University of Cincinnati Medical Center, Veteran Affairs Medical Center, Cincinnati, OH 45221, United States.
authors.forename: Rupak K
authors.initials: RK
authors.lastname: Banerjee
keywords: Intermediate coronary stenosis; Interventional cardiology; Pressure drop coefficient