Evaluation of Local Blood Flow Velocity in Proximal and Distal Coronary Arteries by Laser Doppler Method

Kajiya, Fumihiko; Tomonaga, Go; Tsujioka, Katsuhiko; Ogasawara, Yasuo; Nishihara, Hideaki

doi:10.1115/1.3138511

Cited by 87 publications

(27 citation statements)

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“…Profiles of velocity in the plane of the myocardial curvature have been reported by several investigators using pulsed-Doppler ultrasound, 2728 laser Doppler anemometry, 29 and hot film anemometry. 28 There have been inconsistent observations as to the configuration of the velocity profiles in the coronary arteries.…”

Section: Discussionmentioning

confidence: 97%

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Profiles of velocity in coronary arteries of dogs indicate lower shear rate along inner arterial curvature.

1989

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Multiple-range, gate-pulsed Doppler veloclmetry was used to examine the velocity profile within the lumen of the left circumflex and toft anterior descending coronary arteries of 10 anesthetized, open-chest dogs at rest and after administration of propranolol and Intracoronary adenoslne. The peak dlastollc and mean profiles of velocity were skewed away from the Inner walls of the vessels (p<0.01). The extent of skewness was not affected by propranolol or adenoslne. The shear rates were significantly lower along the Inner wall In comparison to the outer wall under all conditions In both the left circumflex and the left anterior descending coronary arteries (p<0.017). Irrespective of the levels of flow, therefore, the velocity profiles were skewed away from the Inner wall of the coronary arteries. Consequently, the shear rates were lower along the Inner walls of the coronary arteries. (Arteriosclerosis 9:167-175, March/April 1989) C urvature of arteries alters the shear stress at the wall from that which would occur in straight vessels. The magnitude and location of high-and low-shear stress may be important because shear stress may contribute to atherogenesis. Theories that implicate either low-shear stresses or high-shear stresses in the pathogenesis of atherosclerosis have been proposed.1 -6 Subsequent investigations have shown an influence of shear upon endothelial structure, function, and intimal thickening. 9 -22 In the coronary vasculature, the large epicardial vessels display a significant curvature as they course over the surface of the heart. In flow through curved tubes, the profile of velocity is skewed away from the inner wall, resulting in lower shear stresses near the inner curvature of the tube. 23 In curved tubes, the effects of increased flow on wall shear are not easily predicted. Increased flow in a curved tube may increase the skewness of the velocity profile, altering the relative magnitude of shear at the inner and outer walls. 23 In addition, high flows can introduce secondary flows in the velocity profile. 24 This factor may tend to reverse the skewness of the velocity profile in a curved tube. 23 Although several investigators have reported the profile of velocity in the coronary arteries of animals, 26 -29 there is no general agreement as to the configuration of the velocity profiles in the coronary arteries.The shear stress at the wall of arteries caused by the flowing blood is defined as the product of the effective blood viscosity and the shear rate. 3031 The shear rate at the wall is the velocity gradient at the wall (du/dy, where u From the Henry Ford Heart and Vascular Institute, Detroit, Michigan.This work was supported in part by Grant HL23669-08 from the U.S. Public Health Sendee, National Heart, Lung, and Blood Institute.Address for reprints: Paul D. Stein, M.D., Henry Ford Heart and Vascular Institute, 2799 West Grand Boulevard, Detroit, Ml 48202.Received December 21, 1987; revision accepted September 29, 1988. is velocity in the axial direction and y is the distanc...

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Section: Discussionmentioning

confidence: 97%

“…Wells and associates, 28 using pulsed-Doppler ultrasound velodmetry, observed no skewing. Kajiya and associates, 29 using laser Doppler anemometry, showed inconsistent skewing of the velocity profile in the circumflex coronary artery of anesthetized dogs.…”

Section: Discussionmentioning

confidence: 98%

Profiles of velocity in coronary arteries of dogs indicate lower shear rate along inner arterial curvature.

1989

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“…14 - 18 In previous studies, we have shown that the blood flow velocities in the proximal and distal coronary arteries 2 and in the great cardiac vein 6 can be successfully measured by inserting the optical fiber into the vessels with the aid of a light rubber cuff. Kilpatrick et aJ 19 also have shown the high level of accuracy of the laser Doppler anemometer with an optical fiber catheter for measurements of coronary sinus flow in the dog.…”

Section: Figure 8 Bar Graphs Showing Comparison Of Blood Flow Velocimentioning

confidence: 99%

Analysis of the characteristics of the flow velocity waveforms in left atrial small arteries and veins in the dog.

Kajiya

Tsujioka

Ogasawara

et al. 1989

Circulation Research

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To clarify the characteristics of the phasic blood velocity pattern in small arteries and veins on the left atrial surface, we used our newly developed fiber-optic laser Doppler velocimeter. We intended particularly to examine the Influence of atrial contraction and relaxation on velocity waveforms to obtain some insight into the nature of the mechanical force acting on the atrial intramyocardial vascular beds. In 14 anesthetized open-chest dogs, the left atrial appendage was gently displaced to expose small branches of the artery and vein. Vessels with an outer diameter of about 150-500 fim were chosen for the measurements because their walls are transparent to laser light. The fiber tip (velocity sensor) was fixed on the vessel surface with a drop of cyanoacrylate when good-quality Doppler signals were consistently observed. Additional experiments with three dogs were performed to observe the blood velocities in the atrial artery and vein during arrhythmia. The blood velocity waveform in the artery was similar to the pattern of aortic pressure during ventricular ejection (peak velocity, 18.8±7.8 cm/sec) but was characterized by a pronounced dip during atrial contraction. The temporal coincidence between the dip formation and atrial contraction was confirmed during atrial flutter with an atrioventricular block. After isoproterenol administration (2 fig i.v.), the acceleration rate of the forward flow velocity increased by 176% (p<0.05), and reverse flow appeared during atrial contraction in five cases out of eight (p=0.013). The blood flow velocity in atrial small veins, on the other hand, was predominant during atrial contraction (peak velocity, 15.6±5.8 cm/sec). Isoproterenol increased the acceleration rate of this forward flow velocity by 121% (/><0.01). Nitroglycerin did not change the blood velocity waveform significantly in atrial arteries or in veins. The phase opposition between arterial inflow into and venous outflow from the atrial myocardium indicates that a large portion of the coronary inflow to the atrial myocardium may be stored due to the presence of atrial myocardial vascular capacitance. We conclude that atrial myocardial contraction impedes atrial inflow and promotes venous outflow from atrial capacitance vessels.

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“…There have been some studies on the flow pattern of CABG and most of them consist of experimental in vitro observations of the dye flow, 4 the two-dimensional simulation of CABG, 5 and the measurement of the flow quantity by laser Doppler or a magnetic flowmeter. [6][7][8][9] Computational fluid dynamics (CFD) has been a major tool for designing aircrafts, ships, and automobiles. CFD can demonstrate the rationality of the optimal flow in many complex problems, but has so far been only limitedly applied to designing cardiac surgery except for a few studies.…”

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confidence: 99%

Three-Dimensional Simulation of Coronary Artery Bypass Grafting with the Use of Computational Fluid Dynamics

Song

Sato²,

Ueda

2000

Surgery Today

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In search of an optimal anastomosis conformation in coronary artery bypass grafting surgery and flow visualization, three-dimensional simulation of the anastomosis has been developed with the use of computational fluid dynamics. To simulate the surgery, a Y-figure model with proximal stenosis was developed in three cases according to angles ranging from 10 degrees to 30 degrees. The boundary condition of velocity and flow of the model were given based on the average velocity and flow of coronary artery measured intraoperatively. Using this information, the fluid dynamics of three models were calculated by commercial computation fluid dynamics code. The convergent results showed the least recirculating jet in the 10 degrees anastomosis without back flow into the graft. The total energy loss in the field was most affected in 30 degrees anastomosis. The wall shear stress profile showed maximum values at the heel region where recirculating jet takes place. This simulation suggests that the more acute is the angle of anastomosis, the smaller is the energy loss. Based on this phenomenon, surgery should therefore be designed to obtain as acute an angle as possible in light of the fluid dynamics.

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Evaluation of Local Blood Flow Velocity in Proximal and Distal Coronary Arteries by Laser Doppler Method

Cited by 87 publications

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Profiles of velocity in coronary arteries of dogs indicate lower shear rate along inner arterial curvature.

Profiles of velocity in coronary arteries of dogs indicate lower shear rate along inner arterial curvature.

Analysis of the characteristics of the flow velocity waveforms in left atrial small arteries and veins in the dog.

Three-Dimensional Simulation of Coronary Artery Bypass Grafting with the Use of Computational Fluid Dynamics

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