Which diameter and angle rule provides optimal flow patterns in a coronary bifurcation?

Area of Science:

• Cardiovascular Science
• Biomedical Engineering
• Fluid Dynamics

Background:

• Epicardial coronary artery bifurcations are crucial in atherogenesis.
• Murray's cubed diameter law and bifurcation angles were traditionally assumed optimal for flow.
• A new HK diameter model based on minimum energy has been proposed.

Purpose of the Study:

• To derive a bifurcation angle rule for the HK diameter model.
• To compare streamline flow in HK and Murray-type bifurcations.
• To evaluate the implications for percutaneous coronary intervention.

Main Methods:

• Analysis of coronary casts to determine adherence to diameter models.
• Finite element modeling to simulate blood flow patterns.
• Measurement of inlet velocity and pressure using ComboWire.

Main Results:

• Coronary bifurcations more closely followed the HK diameter model and angle rule than Murray's model.
• Murray-type bifurcations showed decreased wall shear stress (WSS) and increased oscillatory shear index (OSI).
• HK-type bifurcations exhibited more optimal flow patterns with higher WSS and lower OSI.

Conclusions:

• The HK diameter model and its associated angle rule provide a more accurate representation of coronary artery bifurcations.
• HK-type bifurcations demonstrate superior flow dynamics compared to traditional Murray-type bifurcations.
• Findings have significant implications for optimizing bifurcation angles and diameters in percutaneous coronary interventions.