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Updated: Feb 22, 2026
In vitro Assessment of Aortic Regurgitation Using Four-Dimensional Flow Magnetic Resonance Imaging
Published on: February 25, 2022
A numerical study of the hemodynamic effect of the aortic valve on coronary flow
Shaily Wald1,2, Alex Liberzon1, Idit Avrahami3
1School of Mechanical Engineering, Tel Aviv University, 69978, Tel Aviv, Israel.
Insights
Severe aortic stenosis increases rest coronary blood flow, while transcatheter aortic valve implantation decreases it. This study explains these hemodynamic changes using computational fluid dynamics.
Area of Science:
- Cardiovascular Physiology
- Biomedical Engineering
- Computational Fluid Dynamics
Background:
- Coronary perfusion during diastole is pressure-dependent, influenced by aortic root hemodynamics and valve function.
- Severe aortic stenosis (AS) is clinically associated with increased rest coronary blood flow (CBF) and diastolic dysfunction, yet the underlying mechanisms remain unclear.
- Transcatheter aortic valve implantation (TAVI) reduces rest CBF, but the reasons for this change post-procedure are not fully understood.
Purpose of the Study:
- To investigate the impact of severe aortic stenosis (AS) and transcatheter aortic valve implantation (TAVI) on coronary blood flow (CBF) during rest conditions using numerical simulations.
- To elucidate the hemodynamic mechanisms responsible for the observed changes in rest CBF in AS patients before and after TAVI.
Main Methods:
- Development and analysis of five distinct 2D computational fluid dynamics (CFD) models simulating blood flow in the aortic root.
- Models included a healthy valve, two cases of severe aortic stenosis (AS), and two cases representing transcatheter aortic valve implantation (TAVI).
- Time-dependent computational fluid-structure interaction (FSI) simulations incorporated flexible aortic valve leaflet dynamics and variable coronary artery resistance.
Main Results:
- The numerical study successfully replicated key hemodynamic effects in the aortic root under different valve conditions.
- The model provided explanations for the elevated rest CBF observed in AS and its subsequent reduction following TAVI.
- Hemodynamic alterations near the closing valve leaflets were identified as a critical factor influencing coronary perfusion changes.
Conclusions:
- The 2D CFD model effectively explains the hemodynamic basis for altered coronary blood flow in severe aortic stenosis and after TAVI.
- The study highlights the significant role of aortic root flow dynamics and valve-structure interactions in regulating coronary perfusion.
- Findings contribute to a better understanding of cardiovascular physiology in valvular heart disease and post-intervention changes.
Abstract:
During diastole, coronary perfusion depends on the pressure drop between the myocardial tissue and the coronary origin located at the aortic root. This pressure difference is influenced by the flow field near the closing valve leaflets. Clinical evidence is conclusive that patients with severe aortic stenosis (AS) suffer from diastolic dysfunction during hyperemia, but show increased coronary blood flow (CBF) during rest. Transcatheter aortic valve implantation (TAVI) was shown to decrease rest CBF along with its main purpose of improving the aortic flow and reducing the risk of heart failure. Physiological or pathological factors do not provide a clear explanation for the increase in rest CBF due to AS and its decrease immediately after TAVI. In this manuscript, we present a numerical study that examines the impact of AS and TAVI on CBF during rest conditions. The study compares the hemodynamics of five different 2D numerical models: a baseline "healthy valve" case, two AS cases and two TAVI cases. The analysis used time-dependent computational fluid-structure interaction simulations of blood flow in the aortic root including the dynamics of the flexible valve leaflets and the varying resistance of the coronary arteries. Despite its simplifications, our 2D model succeeded to capture the major effects that dominate the hemodynamics in the aortic root and to explain the hemodynamic effect that leads to the changes in CBF found in in vitro and clinical studies.
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