1993 Fiscal Year Final Research Report Summary
Effects of Vessel Wall Elasticity on Blood Flow
| Project/Area Number |
04670845
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Thoracic surgery
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| Research Institution | National Cardiovascular Center Research Institute |
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Principal Investigator |
SEKI Junji National Cardiovascular Ctr Res Inst, Deptbiomed Eng, Research Fellow, 生体工学部, 室長 (20163082)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAMIZAWA Keiichi National Cardiovascular Ctr Res Inst, Deptbiomed Eng, Research Fellow, 生体工学部, 室員 (10163312)
MATSUDA Takehisa National Cardiovascular Ctr Res Inst, Deptbiomed Eng, Head of Dept, 生体工学部, 部長 (60142189)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Vessel Wall Elasticity / Pulsatile Flow / Turbulence Transition / Laser-Doppler Anemometer / Wave Propagation / Propagation Velocity / Network Architecture / Spontaneous Hypertension |
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| Research Abstract |
In vitro and in vivo experiments were conducted to study the effects of the vessel wall elasticity on the blood flow characteristics focusing on thegeneration and development of blood flow turbulence and on the propagation of flow pulse in microvessels, respectively.
In in vitro experiments, a fully developed pulsatile flow (sinusoidal flow in addition to mean flow) was measured by a laser-Doppler anemometer. The velocity waveforms and the velocity profiles in the tube cross-section were obtained under various conditions of pulsatile flow. When the flow was not turbulent, the velodcity waveforms and the velocity proviles agreed well with the theoretical predictions. Regarding the turbulence transition, the centerline velocity was recorded as the mean Reynolds number was increased with a fixed frequency and amplitude of pulsation. The flow became turbulent in the deceleration phase when the mean Reynolds number was larger than a critical value, the transition Reynolds number. The transis
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ion Reynolds number was 2400 at the modulation Reynolds number of 880 and the freqyency parameter of 5.9. Considering the transision Reynolds number of steady flow was 2000, it means that the flow is stabilized under the pulsatile condition.
In in vivo experiments, propagation of flow pulse was studied in microvascular networks of rat mesentery by a fiber-optic laser-Doppler anemometer microscope (FLDAM). The mean flow rate, amplitude of the flow pulsation, phase lag of the microvascular flow relative to the carotid arterial pressure were determined in arterioles, capillaries and venules. The arterio-venous distributions of the mean flow, flow amplitude and phase lag were analyzed based on an idealized model of the microvasculature. The difference observed in the distributions between spontaneously hypertensive rats (SHR) and normotensive control rats (WKY) were explained from the theoretical model by the rarefaction of small arterioles in SHR.Thepropagation velocity of flow pulse was also measured in arterioles. The elastic modulus of the vessel wall estimated from the propagation velocitywas in the range from 2x10^6 to 2x10^7 dyn/cm^2, which was in the same order of the elastic modulus for large arteries. Less
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