Browne Leonard D, Bashar Khalid, Griffin Philip, Kavanagh Eamon G, Walsh Stewart R, Walsh Michael T
Centre for Applied Biomedical Engineering Research (CABER), Department of Mechanical, Aeronautical and Biomedical Engineering, Materials and Surface Science Institute, The Health Research Institute, University of Limerick, Limerick, Ireland.
Department of Vascular Surgery, Limerick University Hospital, Dooradoyle, Limerick, Ireland.
PLoS One. 2015 Dec 30;10(12):e0145795. doi: 10.1371/journal.pone.0145795. eCollection 2015.
Non-maturation and post-maturation venous stenosis are the primary causes of failure within arteriovenous fistulae (AVFs). Although the exact mechanisms triggering failure remain unclear, abnormal hemodynamic profiles are thought to mediate vascular remodelling and can adversely impact on fistula patency.
The review aims to clarify the role of shear stress on outward remodelling during maturation and evaluate the evidence supporting theories related to the localisation and development of intimal hyperplasia within AVFs.
A systematic review of studies comparing remodelling data with hemodynamic data obtained from computational fluid dynamics of AVFs during and after maturation was conducted.
Outward remodelling occurred to reduce or normalise the level of shear stress over time in fistulae with a large radius of curvature (curved) whereas shear stress was found to augment over time in fistulae with a small radius of curvature (straight) coinciding with minimal to no increases in lumen area. Although this review highlighted that there is a growing body of evidence suggesting low and oscillating shear stress may stimulate the initiation and development of intimal medial thickening within AVFs. Further lines of evidence are needed to support the disturbed flow theory and outward remodelling findings before surgical configurations and treatment strategies are optimised to conform to them. This review highlighted that variation between the time of analysis, classification of IH, resolution of simulations, data processing techniques and omission of various shear stress metrics prevented forming pooling of data amongst studies.
Standardised measurements and data processing techniques are needed to comprehensively evaluate the relationship between shear stress and intimal medial thickening. Advances in image acquisition and flow quantifications coupled with the increasing prevalence of longitudinal studies commencing from fistula creation offer viable techniques and strategies to robustly evaluate the relationship between shear stress and remodelling during maturation and thereafter.
未成熟和成熟后静脉狭窄是动静脉内瘘（AVF）失败的主要原因。尽管引发失败的确切机制尚不清楚，但异常的血流动力学特征被认为可介导血管重塑，并可能对瘘管通畅性产生不利影响。
本综述旨在阐明剪切应力在成熟过程中对外向重塑的作用，并评估支持与AVF内膜增生的定位和发展相关理论的证据。
对将成熟期间和成熟后AVF的重塑数据与通过计算流体动力学获得的血流动力学数据进行比较的研究进行系统综述。
随着时间的推移，曲率半径大的瘘管（弯曲型）会发生外向重塑，以降低或使剪切应力水平正常化，而曲率半径小的瘘管（直型）中剪切应力会随着时间增加，同时管腔面积增加很少或没有增加。尽管本综述强调，越来越多的证据表明低剪切应力和振荡剪切应力可能会刺激AVF内内膜中层增厚的起始和发展。在优化手术配置和治疗策略以符合这些理论之前，还需要更多证据来支持紊乱血流理论和外向重塑的研究结果。本综述强调，分析时间、内膜增生的分类、模拟分辨率、数据处理技术以及各种剪切应力指标的遗漏之间的差异，阻碍了在各项研究之间形成数据汇总。
需要标准化的测量和数据处理技术来全面评估剪切应力与内膜中层增厚之间的关系。图像采集和血流定量技术的进步，以及从瘘管创建开始的纵向研究的日益普及，为有力评估成熟期间及之后剪切应力与重塑之间的关系提供了可行的技术和策略。
