论文信息 - The improvement of the shear stress and oscillatory shear index of coronary arteries during Enhanced External Counterpulsation in patients with coronary heart disease

The improvement of the shear stress and oscillatory shear index of coronary arteries during Enhanced External Counterpulsation in patients with coronary heart disease

Background Enhanced External Counterpulsation (EECP) can chronically relieve ischemic chest pain and improve the prognosis of coronary heart disease (CHD). Despite its role in mitigating heart complications, EECP and the mechanisms behind its therapeutic nature, such as its effects on blood flow hemodynamics, are still not fully understood. This study aims to elucidate the effect of EECP on significant hemodynamic parameters in the coronary arterial tree. Methods A finite volume method was used in conjunction with the inlet pressure wave (surrogated by the measured aortic pressure) before and during EECP and outlet flow resistance, assuming the blood as newtonian fluid. The time-average wall shear stress (TAWSS) and oscillatory shear index (OSI) were determined from the flow field. Results Regardless of the degree of vascular stenosis, hemodynamic conditions and flow patterns could be improved during EECP. In comparison with the original tree, the tree with a severe stenosis (75% area stenosis) demonstrated more significant improvement in hemodynamic conditions and flow patterns during EECP, with surface area ratio of TAWSS risk area (SAR-TAWSS) reduced from 12.3% to 6.7% (vs. SAR-TAWSS reduced from 7.2% to 5.6% in the original tree) and surface area ratio of OSI risk area (SAR-OSI) reduced from 6.8% to 2.5% (vs. SAR-OSI of both 0% before and during EECP in the original tree because of mild stenosis). Moreover, it was also shown that small ratio of diastolic pressure (D) and systolic pressure (S) (D/S) could only improve the hemodynamic condition mildly. The SAR-TAWSS reduction ratio significantly increased as D/S became larger. Conclusions A key finding of the study was that the improvement of hemodynamic conditions along the LMCA trees during EECP became more significant with the increase of D/S and the severity degree of stenoses at the bifurcation site. These findings have important implications on EECP as adjuvant therapy before or after percutaneous coronary intervention (PCI) in patients with diffuse atherosclerosis.

[1] R C Schroter,et al. Proposal of a shear dependent mass transfer mechanism for atherogenesis. , 1971, Clinical science.

[2] R. Mates,et al. Zero-flow pressures and pressure-flow relationships during single long diastoles in the canine coronary bed before and during maximum vasodilation. Limited influence of capacitive effects. , 1981, The Journal of clinical investigation.

[3] C. Hartley,et al. Diastolic coronary artery pressure-flow velocity relationships in conscious man. , 1984, Cardiovascular research.

[4] D. Ku,et al. Pulsatile Flow and Atherosclerosis in the Human Carotid Bifurcation: Positive Correlation between Plaque Location and Low and Oscillating Shear Stress , 1985, Arteriosclerosis.

[5] Michael F. O'Rourke,et al. McDonald's blood flow in arteries : theoretic, experimental, and clinical principles , 1990 .

[6] Y. Fung,et al. Blood Flow in Arteries , 1997 .

[7] W. Nichols,et al. McDonald's Blood Flow in Arteries: Theoretical, Experimental and Clinical Principles , 1998 .

[8] G S Kassab,et al. On the design of the coronary arterial tree: a generalization of Murray's law , 1999 .

[9] A Benslimane,et al. Stenting of bifurcation lesions: Classification, treatments, and results , 2000, Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions.

[10] G. Truskey,et al. Hemodynamic parameters and early intimal thickening in branching blood vessels. , 2001, Critical reviews in biomedical engineering.

[11] W. Grossman,et al. Left Ventricular Systolic Unloading and Augmentation of Intracoronary Pressure and Doppler Flow During Enhanced External Counterpulsation , 2002, Circulation.

[12] M. Sonka,et al. Fluid Dynamic Analysis in a Human Left Anterior Descending Coronary Artery with Arterial Motion , 2004, Annals of Biomedical Engineering.

[13] Maria Siebes,et al. Physiological Basis of Clinically Used Coronary Hemodynamic Indices , 2006, Circulation.

[14] Ghassan S Kassab,et al. Analysis of blood flow in an out-of-plane CABG model. , 2006, American journal of physiology. Heart and circulatory physiology.

[15] Thomas Wischgoll,et al. Flow patterns in three-dimensional porcine epicardial coronary arterial tree. , 2007, American journal of physiology. Heart and circulatory physiology.

[16] Yan Zhang,et al. Enhanced External Counterpulsation Inhibits Intimal Hyperplasia by Modifying Shear Stress–Responsive Gene Expression in Hypercholesterolemic Pigs , 2007, Circulation.

[17] E. Edelman,et al. Prediction of the Localization of High-Risk Coronary Atherosclerotic Plaques on the Basis of Low Endothelial Shear Stress: An Intravascular Ultrasound and Histopathology Natural History Study , 2008, Circulation.

[18] A. Louis,et al. Enhanced External Counterpulsation in the Treatment of Chronic Refractory Angina: A Long‐term Follow‐up Outcome from the International Enhanced External Counterpulsation Patient Registry , 2008, Clinical cardiology.

[19] Ghassan S Kassab,et al. Scaling of myocardial mass to flow and morphometry of coronary arteries. , 2008, Journal of applied physiology.

[20] Yiannis S Chatzizisis,et al. The role of low endothelial shear stress in the conversion of atherosclerotic lesions from stable to unstable plaque , 2009, Current opinion in cardiology.

[21] U. Siebert,et al. Fractional flow reserve versus angiography for guiding percutaneous coronary intervention. , 2009, The New England journal of medicine.