二叶式主动脉瓣病变中主动脉瓣狭窄和主动脉直径决定壁切应力增加的程度。
Aortic valve stenosis and aortic diameters determine the extent of increased wall shear stress in bicuspid aortic valve disease.
机构信息
Department of Cardiothoracic Surgery, Academic Medical Center, Amsterdam, the Netherlands.
Department of Radiology, Academic Medical Center, Amsterdam, the Netherlands.
出版信息
J Magn Reson Imaging. 2018 Aug;48(2):522-530. doi: 10.1002/jmri.25956. Epub 2018 Feb 16.
BACKGROUND
Use of 4-dimensional flow magnetic resonance imaging (4D-flow MRI) derived wall shear stress (WSS) heat maps enables identification of regions in the ascending aorta with increased WSS. These regions are subject to dysregulation of the extracellular matrix and elastic fiber degeneration, which is associated with aortic dilatation and dissection.
PURPOSE
To evaluate the effect of the presence of aortic valve stenosis and the aortic diameter on the peak WSS and surface area of increased WSS in the ascending aorta.
STUDY TYPE
Prospective.
SUBJECTS
In all, 48 bicuspid aortic valve (BAV) patients (38.1 ± 12.4 years) and 25 age- and gender-matched healthy individuals.
FIELD STRENGTH/SEQUENCE: Time-resolved 3D phase contrast MRI with three-directional velocity encoding at 3.0T.
ASSESSMENT
Peak systolic velocity, WSS, and aortic diameters were assessed in the ascending aorta and 3D heat maps were used to identify regions with elevated WSS.
STATISTICAL TESTS
Comparisons between groups were performed by t-tests. Correlations were investigated by univariate and multivariate regression analysis.
RESULTS
Elevated WSS was present in 15 ± 11% (range; 1-35%) of the surface area of the ascending aorta of BAV patients with aortic valve stenosis (AS) (n = 10) and in 6 ± 8% (range; 0-31%) of the ascending aorta of BAV patients without AS (P = 0.005). The mid-ascending aortic diameter negatively correlated with the peak ascending aortic WSS (R = -0.413, P = 0.004) and the surface area of elevated WSS (R = -0.419, P = 0.003). Multivariate linear regression analysis yielded that the height of peak WSS and the amount of elevated WSS depended individually on the presence of aortic valve stenosis and the diameter of the ascending aorta.
DATA CONCLUSION
The extent of increased WSS in the ascending aorta of BAV patients depends on the presence of aortic valve stenosis and aortic dilatation and is most pronounced in the presence of AS and a nondilated ascending aorta.
LEVEL OF EVIDENCE
2 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2018;48:522-530.
背景
使用 4 维流磁共振成像（4D-flow MRI）得出的壁面切应力（WSS）热图可识别升主动脉中 WSS 增加的区域。这些区域易受到细胞外基质和弹性纤维退化的失调影响，这与主动脉扩张和夹层有关。
目的
评估主动脉瓣狭窄的存在和主动脉直径对升主动脉峰值 WSS 和 WSS 增加表面积的影响。
研究类型
前瞻性。
受试者
共 48 名二叶式主动脉瓣（BAV）患者（38.1±12.4 岁）和 25 名年龄和性别匹配的健康个体。
磁场强度/序列：在 3.0T 下进行 3 维相位对比 MRI 测量，采用三维方向速度编码。
评估
在升主动脉中评估收缩期峰值速度、WSS 和主动脉直径，并使用 3D 热图来识别 WSS 升高的区域。
统计学检验
通过 t 检验比较两组间的差异。采用单变量和多变量回归分析进行相关性研究。
结果
在主动脉瓣狭窄（AS）的 BAV 患者（n=10）的升主动脉中，有 15±11%（范围，1-35%）的表面区域存在升高的 WSS，而在无 AS 的 BAV 患者（n=10）的升主动脉中，有 6±8%（范围，0-31%）的表面区域存在升高的 WSS（P=0.005）。升主动脉中部直径与升主动脉峰值 WSS（R=-0.413，P=0.004）和 WSS 升高表面积（R=-0.419，P=0.003）呈负相关。多元线性回归分析表明，峰值 WSS 的高度和升高 WSS 的量分别取决于主动脉瓣狭窄的存在和升主动脉的直径。
数据结论
BAV 患者升主动脉中增加的 WSS 程度取决于主动脉瓣狭窄和主动脉扩张的存在，在存在 AS 和不扩张的升主动脉时最为明显。
证据水平
2 技术功效：2 级。J. MAGN. RESON. IMAGING 2018；48：522-530.
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