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Abstract：
OBJECTIVE: Patients with bicuspid aortic valve (BAV) and aortic regurgitation have higher rate of aortic complications compared with patients with BAV and stenosis, as well as BAV without valvular disease. Aortic regurgitation alters blood haemodynamics not only in systole but also during diastole. We therefore sought to investigate wall shear stress (WSS) during the whole cardiac cycle in BAV with aortic regurgitation.
RESULTS: Fifty-seven subjects that underwent 4D flow cardiovascular magnetic resonance imaging were included: 13 patients with BAVs without valve disease, 14 BAVs with aortic regurgitation, 15 BAVs with aortic stenosis, and 22 normal controls with tricuspid aortic valve. Peak and time averaged WSS in systole and diastole and the oscillatory shear index (OSI) in the ascending aorta were computed. Student\'s t-tests were used to compare values between the four groups where the data were normally distributed, and the non-parametric Wilcoxon rank sum tests were used otherwise. BAVs with regurgitation had similar peak and time averaged WSS compared with the patients with BAV without valve disease and with stenosis, and no regions of elevated WSS were found. BAV with aortic regurgitation had twice as high OSI as the other groups (P ≤ 0.001), and mainly in the outer mid-to-distal ascending aorta.
CONCLUSIONS: OSI uniquely characterizes altered WSS patterns in BAVs with aortic regurgitation, and thus could be a haemodynamic marker specific for this specific group that is at higher risk of aortic complications. Future longitudinal studies are needed to verify this hypothesis.
RESULTS: Fifty-seven subjects that underwent 4D flow cardiovascular magnetic resonance imaging were included: 13 patients with BAVs without valve disease, 14 BAVs with aortic regurgitation, 15 BAVs with aortic stenosis, and 22 normal controls with tricuspid aortic valve. Peak and time averaged WSS in systole and diastole and the oscillatory shear index (OSI) in the ascending aorta were computed. Student\'s t-tests were used to compare values between the four groups where the data were normally distributed, and the non-parametric Wilcoxon rank sum tests were used otherwise. BAVs with regurgitation had similar peak and time averaged WSS compared with the patients with BAV without valve disease and with stenosis, and no regions of elevated WSS were found. BAV with aortic regurgitation had twice as high OSI as the other groups (P ≤ 0.001), and mainly in the outer mid-to-distal ascending aorta.
CONCLUSIONS: OSI uniquely characterizes altered WSS patterns in BAVs with aortic regurgitation, and thus could be a haemodynamic marker specific for this specific group that is at higher risk of aortic complications. Future longitudinal studies are needed to verify this hypothesis.
摘要：
目的：与BAV和狭窄患者相比，二叶主动脉瓣（BAV）和主动脉瓣反流患者的主动脉并发症发生率更高，以及无瓣膜疾病的BAV。主动脉瓣返流不仅在收缩期改变血液动力学，还有舒张期.因此，我们试图研究BAV伴有主动脉瓣反流的整个心动周期中的壁切应力（WSS）。
结果：包括57名接受4D血流心血管磁共振成像的受试者：13名无瓣膜疾病的BAVs患者，14例主动脉瓣反流BAVs,15例主动脉瓣狭窄的BAV和22例三尖瓣主动脉瓣（TAV）的正常对照。收缩期和舒张期的峰值和时间平均WSS，计算升主动脉的振荡剪切指数（OSI）。学生t检验用于比较数据呈正态分布的四组之间的值，非参数Wilcoxon秩和检验在其他情况下使用。与没有瓣膜疾病和狭窄的BAV患者相比，反流的BAV具有相似的峰值和时间平均WSS。没有发现WSS升高的区域。BAV伴主动脉瓣反流的OSI是其他组的两倍（p≤0.001），主要位于中远端升主动脉外侧。
结论：OSI独特地表征了主动脉瓣反流的BAVs中WSS模式的改变，因此可能是该特定人群的血液动力学标志物，该人群具有较高的主动脉并发症风险。需要未来的纵向研究来验证这一假设。
结果：包括57名接受4D血流心血管磁共振成像的受试者：13名无瓣膜疾病的BAVs患者，14例主动脉瓣反流BAVs,15例主动脉瓣狭窄的BAV和22例三尖瓣主动脉瓣（TAV）的正常对照。收缩期和舒张期的峰值和时间平均WSS，计算升主动脉的振荡剪切指数（OSI）。学生t检验用于比较数据呈正态分布的四组之间的值，非参数Wilcoxon秩和检验在其他情况下使用。与没有瓣膜疾病和狭窄的BAV患者相比，反流的BAV具有相似的峰值和时间平均WSS。没有发现WSS升高的区域。BAV伴主动脉瓣反流的OSI是其他组的两倍（p≤0.001），主要位于中远端升主动脉外侧。
结论：OSI独特地表征了主动脉瓣反流的BAVs中WSS模式的改变，因此可能是该特定人群的血液动力学标志物，该人群具有较高的主动脉并发症风险。需要未来的纵向研究来验证这一假设。
