Effect of side branch flow upon physiological indices in coronary artery disease

Area of Science:

• Cardiovascular physiology
• Medical imaging analysis
• Computational fluid dynamics

Background:

• Non-invasive computational models estimate fractional flow reserve (FFR) using coronary artery imaging.
• Current models often neglect smaller side branches, potentially affecting flow calculations.

Purpose of the Study:

• To assess the impact of neglecting side branch flow on angiography-derived FFR (vFFR) and volumetric blood flow indices.
• To augment existing computational models with a leakage function to account for side branch flow.

Main Methods:

• A leakage function based on vessel taper (Murray's Law) was integrated into a prior coronary blood flow model.
• The augmented (1D_leaky) and original (1D) models were applied to predict FFR and flow in 146 coronary arteries from 80 patients.
• Model predictions were compared against invasive FFR measurements.

Main Results:

• The leakage function did not significantly alter vFFR predictions.
• Significant impacts were observed on estimated volumetric flow rate and predicted coronary flow reserve.
• Both models demonstrated similar predictive accuracy for vFFR.

Conclusions:

• Neglecting side branches has a limited effect on vFFR prediction accuracy.
• The inclusion of a leakage function significantly influences volumetric flow calculations.
• Careful consideration is needed when using vFFR for quantitative flow assessment due to flow estimation discrepancies.