河北省财政厅 河北省卫生和计划生育委员会 2016年政府资助临床医学优秀人才培养和基础课题研究项目 项目号：361007（家兔静脉生物力学性能的研究）
1.Hebei University Affiliated Hospital;2.Hebei University School of Medicine
目的：建立家兔静脉动脉化模型，以动静脉生物力学的视角对比及探讨静脉动脉化前后以及动静脉之间力学参数的差异，探究其生物力学特性与静脉动脉化之间的联系。 方法：家兔24只，实验组12只，对照组12只。对实验组家兔完成静脉动脉化模型的建立，使得静脉桥中流过动脉血，造模完成后按照预定时间（术后4W）取下静脉桥，同时获取对照组家兔单侧的颈外静脉和颈总动脉，三者同时完成充压拉伸力学测试，并辅以HE染色和免疫组织化学技术观察。 结果：24只家兔无死亡，静脉桥内均血流通畅。结果显示：①随着血管内升压（2.66-26.60kPa），血管外径变化规律均为先变化而后于某一固定值附近浮动:实验组静脉外径变化（8273.68-10338.66μm）、对照组静脉外径变化（10219.1-10606.89μm）、对照组动脉外径变化（4280.42-5669.90μm）；②动静脉力学指标对比：静脉的弹性（斜率k=16.20）比动脉更差（斜率k=58.04）(P < 0.05)，静脉血管的外径随着血管内升压快速增大并达到其弹性极值，相较而言，动脉血管的外径则是缓慢增大；③ HE染色显示，静脉血管的管壁厚度更薄；静脉动脉化后其管壁厚度增加；免疫组织化学结果提示静脉动脉化后PCNA及a-action阳性表达，证实了平滑肌细胞出现增殖，静脉血管桥出现再狭窄趋势；④静脉动脉化前后力学指标对比：移植入动脉系统后的静脉弹性（斜率k=86.26），较移植前（斜率k=16.20）有所提升(P < 0.05)。 结论：①伴随血管内升压，相较动脉，静脉更快地达到其弹性极限，长期处于高压状态下的静脉内膜易因此受损；②静脉动脉化后，随着静脉内膜的逐渐增厚，再狭窄的趋势逐渐明显，其弹性较移植前有所提升。本研究的临床意义：1.通过该力学实验以期找到人体大隐静脉的弹性极值，控制术中大隐静脉管腔内的压力在极值压力之下，以保证在吻合血管之前大隐静脉内膜最低限度地受到损伤，对于提高静脉桥术后中远期通畅率将有着积极的意义；2.从力学的角度适当控制或减低静脉动脉化后静脉桥弹性的增加趋势，对防止静脉移植动脉系统后过早过快地再狭窄可能有着积极作用可行进一步探讨。
Objectives: Create model of vena arterialization. Based on the comparison from arteriovenous biomechanics perspectives and arteriovenous mechanical parameter probe before and after vena arterialization, we could explore the connection between features of its biomechanics and vena arterialization. Methods: Prepare 24 rabbits. 12 for experimental group, another 12 for control group. By setting up vena arterialization model for experimental rabbit group, it allows arterial blood to flow into veins. Vein would be taken according to preset time (4w after surgery) after model creation , while in the meantime, external jugular vein and cephalic artery extracted from control group are acquired. These three items finish compressive tensile mechanics test at the same time. Observation is supported by HE coloration and immune tissue chemical skills. Result: No death occurred among 24 rabbits. Blood flow unobstructed in veins. The result shows that: 1.With the increase of intravascular pressure (2.66-26.60kPa), the changes of vascular outer diameter are first changed and then floating around a fixed value: the changes of vein outer diameter in the experimental group (8273.68-10338.66μm), the changes of vein outer diameter in the control group (10219.1-10606.89μm), and the changes of artery outer diameter in the control group (4280.42-5669.90μm). 2.Comparison of arteriovenous mechanical indexes: the elasticity of veins (slope k=16.20) is worse than that of arteries (slope k=58.04) (P < 0.05). External diameter of vein increases rapidly according to vein’s internal pressure and reach extreme level. Comparatively, such index of artery increases slowly.3. HE coloration shows that vascular wall thickness is thinner, while it becomes thicker after vena arterialization. Immune tissue chemical skills indicated that after vena arterialization, PCNA and a-action shows positive results. It further proves that proliferation exist among smooth muscle cells, and veins show tendency of restenosis again.4. Comparison of mechanical indexes before and after venous arterialization: Vein elasticity after transplantation into the arterial system (slope k=86.26) is improved compared with that before transplantation (slope k=16.20) (P < 0.05). Conclusion: 1. Accompanied by increasing pressure, vein could reach elasticity extremity faster than artery. Under high pressure through a long period of time, vein intima is impaired because of this; 2. After vena arterialization, based on gradual thickening of vein intima, it is obvious for tendency of restenosis, and elasticity has been improved before transplantation. The clinical significances of this research are: 1. we could find the maximum index of vein elasticity of human body based on this mechanical experiment. By controlling the pressure in venous lumen under maximum level during the surgery, it can be assured minimum level of impairment of vein intima before matching. It also means a lot for increasing future primary patency during vein surgery; 2. We could control or lower the tendency of elasticity increasing after vena arterialization from the perspective of mechanics. Further discussion could be actively conducted in prevention of artery transplantation from vein’s restenosis too fast and too soon.