A Numerical Model for Simulating the Hemodynamic Effects of Enhanced External Counterpulsation on Coronary Arteries
Bao Li1, Ke Xu1, Jincheng Liu1
1Department of Biomedical Engineering, Beijing University of Technology, Beijing, China.
Insights
Enhanced external counterpulsation (EECP) improves coronary artery hemodynamics, but excessive pressurization duration increases risks. Clinical treatment should consider additional indicators beyond the Q value for better patient outcomes.
Area of Science:
- Cardiovascular Physiology
- Biomedical Engineering
- Computational Fluid Dynamics
Background:
- Enhanced external counterpulsation (EECP) is used for coronary heart disease, but its hemodynamic mechanisms are not fully understood.
- Current clinical assessment relies on diastolic/systolic blood pressure (Q value), potentially overlooking critical hemodynamic factors.
- Improving the hemodynamic environment for coronary artery endothelial cells is key to EECP's therapeutic benefit.
Purpose of the Study:
- To quantitatively analyze the hemodynamic effects of different EECP modes on coronary artery endothelium using a multi-scale model.
- To investigate the influence of counterpulsation pressure amplitude and duration on hemodynamic parameters.
- To evaluate the limitations of the traditional Q value in assessing EECP efficacy.
Main Methods:
- Development of a standard 0D/3D geometric multi-scale model of the coronary artery.
- Inclusion of neural regulation effects caused by counterpulsation in the model.
- Simulation of various counterpulsation modes and verification with two clinical trials.
Main Results:
- Increased counterpulsation pressure amplitude and duration enhanced coronary blood perfusion and wall shear stress (WSS).
- Increased counterpulsation pressure amplitude and duration reduced the oscillatory shear index (OSI).
- Pressurization duration was the predominant factor, with long durations creating excessive WSS and hemodynamic risks not captured by the Q value.
Conclusions:
- Long-term pressurization in EECP therapy is not recommended due to potential excessive WSS and hemodynamic risks.
- Clinical assessment of EECP should incorporate additional physiological indicators beyond the Q value.
- Optimizing EECP parameters requires a deeper understanding of its quantitative hemodynamic effects on the vascular endothelium.
Abstract:
Traditional enhanced external counterpulsation (EECP) used for the clinical treatment of patients with coronary heart disease only assesses diastolic/systolic blood pressure (Q = D/S > 1.2). However, improvement of the hemodynamic environment surrounding vascular endothelial cells of coronary arteries after long-term application of EECP is the basis of the treatment. Currently, the quantitative hemodynamic mechanism is not well understood. In this study, a standard 0D/3D geometric multi-scale model of the coronary artery was established to simulate the hemodynamic effects of different counterpulsation modes on the vascular endothelium. In this model, the neural regulation caused by counterpulsation was thoroughly considered. Two clinical trials were carried out to verify the numerical calculation model. The results demonstrated that the increase in counterpulsation pressure amplitude and pressurization duration increased coronary blood perfusion and wall shear stress (WSS) and reduced the oscillatory shear index (OSI) of the vascular wall. However, the impact of pressurization duration was the predominant factor. The results of the standard model and the two real individual models indicated that a long pressurization duration would cause more hemodynamic risk areas by resulting in excessive WSS, which could not be reflected by the change in the Q value. Therefore, long-term pressurization during each cardiac cycle therapy is not recommended for patients with coronary heart disease and clinical treatment should not just pay attention to the change in the Q value. Additional physiological indicators can be used to evaluate the effects of counterpulsation treatment.
