Diagnostic performance of a vessel-length-based method to compute the instantaneous wave-free ratio in coronary...

Area of Science:

• Cardiovascular Medicine
• Biomedical Engineering
• Medical Imaging

Background:

• Fractional flow reserve (FFR) is the gold standard for assessing coronary stenosis severity but requires hyperemia.
• Instantaneous wave-free ratio (iFR) is a vasodilator-free index for resting-state assessment.
• Computed tomography-derived iFR (CT-iFR) offers a noninvasive approach to estimate iFR.

Purpose of the Study:

• To develop and validate a vessel-length-based CT-iFR method using patient-specific coronary artery models.
• To evaluate the diagnostic performance of the developed CT-iFR method compared to clinically measured iFR.
• To assess the potential of CT-iFR as a noninvasive aid for percutaneous coronary intervention (PCI) strategy.

Main Methods:

• Coupling a 3D computational fluid dynamics (CFD) model with a lumped parameter model (LPM) for coronary circulation.
• Simulating iFR in a non-hyperemic resting state using a time-varying resistance in the LPM.
• Computing CT-iFR for 50 coronary vessels from 32 patients and comparing with clinical iFR measurements.

Main Results:

• The CT-iFR method demonstrated a high area under the receiver operating characteristics curve (AUC) of 0.93.
• Diagnostic performance metrics included 86% accuracy, 83.3% sensitivity, and 86.8% specificity.
• The CT-iFR values showed strong agreement with clinically measured iFRs.

Conclusions:

• The developed vessel-length-based CT-iFR method is a noninvasive and accurate tool for assessing coronary stenosis.
• CT-iFR can serve as a valuable pre-operative aid for planning percutaneous coronary intervention strategies.
• This noninvasive CT-iFR approach may reduce the need for invasive hyperemia-based assessments.