Numerical study of stenotic side branch hemodynamics in true bifurcation lesions

Area of Science:

• Cardiovascular Research
• Biomedical Engineering
• Computational Fluid Dynamics

Background:

• Coronary bifurcation lesions present complex hemodynamic challenges.
• The clinical significance of side branch (SB) stenosis severity within these lesions remains unclear.
• Current Medina classification may not fully capture the hemodynamic risk of specific bifurcation lesion types.

Purpose of the Study:

• To investigate the hemodynamic impact of different coronary bifurcation lesion types on SB flow and wall shear stress (WSS).
• To assess the risk of coronary branch steal and atherosclerotic progression in SB based on lesion characteristics.
• To evaluate the correlation between lesion type and hemodynamic parameters using computational modeling.

Main Methods:

• Development of computational models simulating coronary bifurcations with varying stenosis severity and location.
• Analysis of blood flow distribution and wall shear stress (WSS) in the SB under different lesion scenarios.
• Comparison of hemodynamic parameters for lesion types (1,0,1), (0,1,1), and (1,1,1) against normal flow conditions.

Main Results:

• Bifurcation type (1,0,1) exhibited a significantly reduced flow ratio (0.25) compared to normal (0.47) and other types.
• A 47% reduction in coronary blood flow was observed in type (1,0,1) lesions, leading to coronary branch steal.
• Decreased blood flow and WSS in the SB correlated with increased stenosis severity, with type (1,0,1) showing WSS below the atherosclerotic growth threshold (<0.5 Pa).

Conclusions:

• Lesion type (1,0,1) poses the highest risk for coronary branch steal and subsequent ischemia.
• The hemodynamic findings for lesion type (1,0,1) suggest a greater propensity for further atherosclerotic growth.
• This study highlights a discrepancy with the Medina classification, indicating (1,0,1) may represent a more critical hemodynamic scenario than typically considered.