A validated predictive model of coronary fractional flow reserve

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Medical Imaging

Background:

• Myocardial fractional flow reserve (FFR) is crucial for assessing coronary stenosis severity.
• Current FFR determination relies on pressure guidewires and lacks a purely analytical, dimension-based model.
• Existing methods do not fully account for energy losses within stenotic regions.

Purpose of the Study:

• To develop and validate a physics-based analytical model for predicting FFR.
• To determine FFR using only stenosis dimensions and hyperemic coronary flow.
• To investigate the influence of various energy loss factors on FFR.

Main Methods:

• An analytical model was derived from the principle of conservation of energy.
• The model incorporates convective, diffusive, and geometric energy losses.
• In vitro and in vivo experiments were conducted to validate the model's predictions against measured pressure drops and FFR.

Main Results:

• The proposed analytical model demonstrated strong agreement with experimental measurements.
• A linear relationship was observed between theoretical and experimental FFR values (r(2) = 0.7).
• Stenosis entrance effects significantly impacted pressure drop, while flow pulsatility and shape had minimal influence.

Conclusions:

• A validated, physics-based analytical model can predict myocardial FFR from stenosis geometry and flow.
• This model eliminates the need for empirical parameters, offering a more fundamental approach to FFR assessment.
• The findings advance the understanding and non-invasive prediction of coronary stenosis severity.