冠狀動脈末稍對側邊接合處流場模擬分析

Numerical Simulation of Pulsating Flow in a Coronary End-to-Side Anastomosis Model

黃星明(Hsing-Ming Huang) ； 湯同達(Tong-Dar Tang) ； 施俊哲(Chun-Che Shih)

《中國航空太空學會學刊》 31卷4期 (1999/12) Pp. 293-299

https://doi.org/10.6124/TAASRC.199912_31(4).06

摘要

本文探討冠狀動脈末梢對側邊移植接合處之血液流場。由於血管繞道移植失敗最常見的原因是接合血管發生內膜肥大現象，而血流變數則是可能導致內膜肥大的原因。研究的方法是利用有限容積法模擬冠狀動脈血管末梢對側邊接合處之流場。數值模擬解析質量及動量守恆方程式而得到定量的流場模擬結果。血液流場定義爲三維、波動流、層流及不可壓縮之牛頓流流場而冠狀動脈與移植血管的截面積比及接合角分別爲1及45度。
本研究依據不同的血管流量比去探討二種情況：移植血管，冠狀動脈下游及冠狀動脈上游的流量比分別是100:100:0（上游完全閉塞）及100:80:20。結果顯示當血管流量比爲100:80:20時，冠狀動脈上游有迴流產生。低平均時間管壁剪應力產生於冠狀動脈上游、冠狀動脈下游內壁及外壁停滯點附近。而這些區域的管壁空間剪應力梯度也較高。因此我們推論低平均時間管壁剪應力與高空間管壁剪應力梯度與內膜肥大的產生是息息相關地。

關鍵字

冠狀動脈 ； 末梢對側邊之接合 ； 管壁剪應力 ； 管壁剪應力梯度

並列摘要

The flow conditions representative of physiological states at a distal end-to-side anastomosis of a coronary artery-graft are investigated. Computational fluid dynamic analyses are conducted and the governing equations are 3-D conservation of continuity and momentum equations. The flow is treated as pulsating, isothermal, laminar,. Newtonian and incompressible. The cross sectional area ratio and bifurcating angle between the coronary artery and graft are determined to be 1 and 45°, respectively.
Two cases of different flow ratios are studied. The flow ratios of graft, artery downstream, and artery upstream are 100:100:0 and 100:80:20. Flow circulation is obvious at the artery upstream throughout the cycle when the flow ratio is 100:80:20. The mean wall shear stress is lower at artery upstream, inner wall of artery downstream, and the stagnation point opposite to the anastomotic junction. High spatial wall shear stress gradient is also observed at these specific locations. Qualitatively speaking, low mean wall shear stress and high spatial wall shear stress gradient are closely related to intimal hyperplasia.

並列關鍵字

Coronary Artery ； End-to-Side Anastomosis ； Wall Shear Stress