正常人降主动脉壁及髂总动脉壁周向张力及平均应力分析

ANALYSIS OF WALL CIRCUMFERENTIAL TENSION AND STRESS ACROSS DESCENDING AORTA AND COMMON ILIAC ARTERY IN HEALTHY PERSON

体中段平面及髂总动脉处有创测压,测量收缩压、舒张压、平均压,MRI下测量动脉内径、壁厚.通过公式计算得出动脉壁周向张力与平均应力,以自身不同部位对照.结果:收缩压自胸主动脉至髂总动脉逐渐升高(P<0.01),舒张压胸主动脉与腹主动脉相差不明显(P>0.05),髂总动脉较胸主动脉与腹主动脉低(P<0.01),平均动脉压肾下腹主动脉最高(P<0.01).自胸主动脉至髂总动脉动脉内径逐渐缩小(P<0.01),管壁亦逐渐变薄(P<0.01).动脉壁周向张力自胸主动脉至髂总动脉逐渐减少(P<0.01).肾下腹主动脉平均应力大于其它动脉(P<0.01),且在一个心动周期中变化幅度最大.结果 肾下腹主动脉处平均应力大于肾上腹主动脉、胸主动脉和髂总动脉,且在一个心动周期中变化幅度最大,可能是造成肾下腹主动脉易于受损而形成动脉瘤的原因.

Objective:Aortic aneurysms appear to have a predilection for the infrarenal aorta. The objective of this study was to explain the predilection using the analysis of wall circumferential tension and stress, and to make further progress in elucidating the pathogenesis of abdominal aortic aneurysms. Methods : We studied 20 healthy person. The systolic, diastolic and mean blood pressure were recorded endoluminally at thoracic, suprarenal, infrarenal aorta, common iliac artery.The radius of vessel and the thickness of vascular wall were measured by MRI scanning. The wall circumferential tension and stress were calculated. Re-suits:The systolic pressure was increased from thoracic aorta to common iliac artery. The diastolic pressure was no difference between thoracic and abdominal aorta, but lower at common iliac artery. The mean pressure was highest at infrarenal aorta. From thoracic aorta to common iliac artery, the radius of vessel became smaller and the thickness of wall became thinner. The wall tension was decreased from thoracic aorta to common iliac artery. The wall stress was biggest at infrarenal aorta. Conclusion :The big wall circumferential stress may be one cause to make infrenal aorta damageable and be prone to form aneurysms.