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Enhanced external counterpulsation (EECP) is a noninvasive treatment method for coronary artery atherosclerosis that acts on the vascular endothelial cells. The intracoronary hemodynamic parameters that influence long-term treatment effect are the fundamental factors for the inhibition of intimal hyperplasia, which cannot be measured in real time. In order to optimize the long-term treatment effect of coronary heart disease, it is necessary to establish a method for quantified calculation of intracoronary hemodynamic parameters during counterpulsation to research the long-term hemodynamic mechanism of EECP. A geometric multiscale model coupled by the zero-dimensional (0D) lumped parameter model and the three-dimensional (3D) model of narrow coronary artery was established for the simulation of intracoronary hemodynamic environment. The 3D model was used to calculate the hemodynamic parameters such as wall shear stress (WSS) and oscillatory shear index (OSI), while the 0D model was used to simulate the blood circulatory system. Sequential pressure was applied to calves, thighs, and buttocks module in 0D model with the consideration of vessel collapse. Hemodynamic performance was compared with clinical reports to verify the effectiveness of the method. There were significant increases of the diastolic blood pressure (DBP), coronary flow, and the area-averaged WSS during application of EECP, while OSI behind stenosis has some decrease. The waveforms of coronary flow has good similarity with the clinical measured waveforms, and the differences between calculated mean arterial pressures (MAPs) and clinical measurements were within 1%. The fundamental factor in the cure of coronary heart disease by EECP is the improvement of WSS and the decrease of OSI. Comparing with the clinical reports, the immediate hemodynamic changes demonstrate the effectiveness of model. Intracoronary hemodynamic parameters during EECP could be acquired and the method could be used to simulate the long-term treatment effect of EECP. Graphical abstract. [ABSTRACT FROM AUTHOR]

Traditional clinical mode of enhanced external counterpulsation is not targeted for different diseases. Specialized strategies in the treatment of enhanced external counterpulsation for coronary heart disease and cerebral ischemic stroke are supposed to be distinguished. The goal of treatment for coronary heart disease is diastolic blood pressure/systolic blood pressure = Q ≥ 1.2 after counterpulsation, while the goal of treatment for cerebral ischemic stroke is the improvement of mean arterial pressure. A computational lumped parameter model was established for the simulation of hemodynamic effect of enhanced external counterpulsation on two diseases. Vessel collapse was considered during the simulation of counterpulsation. Based on different pressurized and decompressed rate, pressurized moment, pressure duration, and pressure amplitude, different counterpulsation modes were applied to the model and the immediate hemodynamic effects were compared. Results showed that the pressure duration and pressure amplitude had most influence on two diseases. For cerebral ischemic stroke, the longer pressure duration and the higher pressure amplitude of thighs, the higher mean arterial pressure; while for coronary heart disease, the value of Q was highest when the pressure end moment was 0.6 s during a 0.88-s cardiac cycle, and Q had a linear increase in the pressure amplitude of buttocks, but little change with the increase of calves and thighs pressure amplitude. For patients with coronary heart disease, the pressure duration was not supposed to be too long to avoid the increase of systolic blood pressure, and the improvement of pressure amplitude of buttocks could promise a positive treatment effect for coronary heart disease. While for patients with cerebral ischemic stroke, both the long pressure duration of each part and the high pressure amplitude of thighs could result in the systolic blood pressure and diastolic blood pressure have a certain increase, thus promoting the maximum mean arterial pressure and a best treatment.The specialized treatment strategies of EECP for cardiovascular and cerebrovascular disease [ABSTRACT FROM AUTHOR]