Delineating coronary epicardial stenosis status from microvascular dysfunction using pressure-drop coefficient from...

Area of Science:

• Cardiovascular Medicine
• Interventional Cardiology
• Diagnostic Imaging

Background:

• Fractional flow reserve (FFR) and coronary flow reserve (CFR) assess coronary artery disease (CAD) functional status.
• Complex hemodynamics in CAD may not be fully explained by pressure or flow alone.
• Pressure-drop coefficient (CDP) combines pressure and flow to distinguish epicardial stenosis (ES) from microvascular disease (MVD).

Purpose of the Study:

• To analyze the diagnostic performance of CDP in relation to FFR and CFR.
• To establish CDP cut-off values for differentiating combinations of ES and MVD.
• To improve the functional assessment of CAD using a composite hemodynamic parameter.

Main Methods:

• Analysis of a global multicenter ILIAS registry including 961 subjects and 1342 measurements.
• Correlation analysis between CDP, FFR, and CFR.
• Receiver operating characteristic (ROC) curve analysis to determine CDP cut-off values for FFR=0.80/0.75 and CFR=2.0.

Main Results:

• CDP showed improved correlation with combined FFR and CFR (logarithmic r=0.75) compared to individual parameters.
• Established CDP cut-off values: 0-15.78 (no disease), 15.78-27.25 (MVD only), 27.25-73.77 (ES only), ≥73.77 (both ES and MVD).
• Similar CDP cut-off ranges were observed for FFR=0.75 and CFR=2.0.

Conclusions:

• Established diagnostic cut-off values for CDP effectively differentiate concomitant epicardial stenosis and microvascular disease.
• CDP offers improved functional assessment of CAD by integrating pressure and flow dynamics.
• This composite parameter aids in delineating complex hemodynamic patterns in coronary artery disease.