Novel insights by 4D Flow imaging on aortic flow physiology after valve-sparing root replacement with or without neosinuses
Novel insights by 4D Flow imaging on aortic flow physiology after valve-sparing root replacement with or without neosinuses
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DOI：
10.1093/icvts/ivx431
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发表时间：
2018-06-01
影响因子：
--
通讯作者：
Gaudino, Mario
中科院分区：
文献类型：
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作者：
Galea, Nicola;Piatti, Filippo;Gaudino, Mario
目的：本研究旨在通过利用4D Flow成像测量体内血流速度场和3D几何流场的能力，评估保留瓣膜的主动脉根部置换术后（有或无Valsalva重建新窦）主动脉根部的血流动力学。10名患者接受了保留瓣膜的牙根置换术，使用带新窦的移植物或直管移植物在术后平均46.5个月时，通过4D Flow成像评价了（各5例）。我们使用内部处理工具来量化相关的批量流量变量（流速、每搏输出量、峰值速度和平均速度）、壁面剪应力和表征移植物和主动脉瓣叶所包围的区域的流动旋转量。尽管整体流量具有相似的峰值速度、流速和冲程容积，（P = 0.31-1.00），新生窦移植物与较低的平均流速相关（P < 0.03）和沿血管壁轴向的壁面剪应力沿着大小在近端牙根水平（P < 0.05），但沿沿着圆周方向（P = 0.22-1.0）与直管移植物相当。新生窦移植物中的血流旋转明显且系统性地更高，其特征在于流线旋转高于270度，几乎是管状移植物的三倍（10.3除以所有主动脉流线的14.0% vs 2.2除以5.7%，P = 0.008）。瓣膜手术期间主动脉窦的重建-保留牙根替换与显著较低的壁面剪应力和在窦水平的有组织的涡流相关，明显使用了直管移植物。这些发现需要在更大规模的研究中得到证实，并且可能对主动脉瓣耐久性具有重要意义。
OBJECTIVES: This study was undertaken to evaluate the flow dynamics in the aortic root after valve-sparing root replacement with and without neosinuses of Valsalva reconstruction, by exploiting the capability of 4D Flow imaging to measure in vivo blood velocity fields and 3D geometric flow patterns.METHODS: Ten patients who underwent valve-sparing root replacement utilizing grafts with neosinuses or straight tube grafts (5 cases each) were evaluated by 4D Flow imaging at a mean of 46.5 months after surgery. We used in-house processing tools to quantify relevant bulk flow variables (flow rate, stroke volume, peak velocity and mean velocity), wall shear stresses and the amount of flow rotation characterizing the region enclosed by the graft and the aortic valve leaflets.RESULTS: Despite bulk flows with similar peak velocities, flow rates and stroke volumes (P = 0.31-1.00), the neosinuses graft was associated with a lower mean velocity (P < 0.03) and magnitude of wall shear stress along the axial direction of the vessel wall (P < 0.05) at the proximal root level but remained comparable along the circumferential direction (P = 0.22-1.0) to the straight tube graft. Flow rotation was evidently and systematically higher in the neosinuses grafts, characterized by streamline rotations higher than 270 degrees, nearly triple that of tubular grafts (10.3 divided by 14.0% of all aortic streamline vs 2.2 divided by 5.7%, P = 0.008).CONCLUSIONS: Recreation of the sinuses of Valsalva during valve-sparing root replacement is associated with significantly lower wall shear stress and organized vortical flows at the level of the sinus that are not evident using the straight tube graft. These findings need confirmation in larger studies and could have important implications in terms of aortic valve durability.