Hardy-Stashin J, Meyer W W, Kauffman S L
Atherosclerosis. 1980 Nov;37(3):399-402. doi: 10.1016/0021-9150(80)90144-6.
Branching coefficient or "area ratio" is the ratio of the sum of the cross-sectional areas of the daughter vessels of a bifurcation to that of the parent stem. The value of area ratio is important for the assessment of flow patterns in the bifurcation and, consequently, of its functional load. In this series of cases, the area ratio was determined in aortic bifurcations of 19 young persons who died suddenly. The specimens were distended during fixation. The area ratio found in this study (1.18 +/- 0.6 SE) corresponded to the optimal value (1.15) predicted on a theoretical basis for an equibifurcation. Our ratio demonstrates an increase of 1.18 in size of the vascular bed of the human aortic bifurcation. We found a significant difference between the aortic circumference measured at the level of the divider compared with the circumference 2-2.5 cm above the bifurcation. The precise level of measurement is therefore critical for a correct determination of the area ratio of the aortic bifurcation and may explain varying values reported in the literature. Deviation from optimal value, e.g. with age, may be accompanied by increased mechanical stress and could favor the prominent involvement of aortic bifurcation by atherosclerotic lesions in man.
分支系数或“面积比”是指分叉处子血管横截面积总和与母干横截面积的比值。面积比的值对于评估分叉处的血流模式以及由此产生的功能负荷很重要。在这一系列病例中，对19名猝死年轻人的主动脉分叉处测定了面积比。标本在固定过程中被扩张。本研究中发现的面积比（1.18±0.6标准误）与理论上预测的等分叉的最佳值（1.15）相符。我们的比值表明人类主动脉分叉处血管床大小增加了1.18倍。我们发现，在分叉处测量的主动脉周长与分叉上方2 - 2.5厘米处的周长相比存在显著差异。因此，精确的测量水平对于正确确定主动脉分叉处的面积比至关重要，这可能解释了文献中报道的不同值。偏离最佳值，例如随着年龄增长，可能会伴随着机械应力增加，并可能促使人类主动脉分叉处更容易出现动脉粥样硬化病变。
