Quantification of Retrograde Blood Flow in the Descending Aorta Using Transesophageal Echocardiography in Comparison to 4D Flow MRI
Quantification of Retrograde Blood Flow in the Descending Aorta Using Transesophageal Echocardiography in Comparison to 4D Flow MRI
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DOI：
10.1159/000381682
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发表时间：
2015-06-01
影响因子：
2.9
通讯作者：
Harloff, Andreas
中科院分区：
文献类型：
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作者：
Wehrum, Thomas;Kams, Miriam;Harloff, Andreas
背景：降主动脉近端(DAO)的逆行舒张期血流将4 mm厚的斑块与脑供血动脉连接起来，先前已被认为是脑血栓的可能来源。目前，只有4D Flow MRI能够显示和量化DAO体内潜在的逆行栓塞途径。因此，我们的目标是测试是否可以通过常规的经食道二维超声心动图(TEE)来评估逆行血流的程度。方法：对48例急性卒中患者进行常规TEE检查，采用20 mm二维超声心动图，在90~140°多普勒角度下，对主动脉弓与DAO之间的移行区进行多普勒检查。应用4DFlow磁共振成像技术，对逆行和顺行的速度-时间-积分(VTI)进行研究，计算VTI比值(VTI)，并与该部位逆行路径长度进行相关分析。用受试者工作特征(ROC)曲线评价VTI比率的阈值，以区分大的(<3 cm)和小的(<3 cm)逆行血流范围。结果：TEE测量部位VTI比值平均为0.53+/-0.16，逆行入弓的平均长度为3.1+/-1.4 cm。VTI比率是逆行路径长度的独立预测因子(r=0.44；p=0.002)。ROC分析的VTI比值阈值为0.6012，敏感性为0.5，特异性为0.92，阳性预测值为0.84，阴性预测值为0.68。相应地，11例(22.91%)患者的VTI比值截断值为0.6012，相应的逆行路径长度为3 cm。结论：TEE可以预测逆行路径的长度。因此，它可能为在大规模研究中研究DAO血流逆转的独立预测因素提供一种经济有效的方法。然而，在临床环境下，TEE作为高逆行血流的筛查工具的价值有限，因为只有大约23%的患者可以避免4D Flow MRI，这对于准确评估DAO体内斑块的个别栓塞途径仍然是不可或缺的。(C)2015年S.Karger AG，巴塞尔
Background: Retrograde diastolic blood flow in the proximal descending aorta (DAo), which connects plaques >= 4 mm thickness with brain-supplying arteries, has previously been identified as a possible source of brain embolism. Currently, only 4D flow MRI is able to visualize and quantify potential retrograde embolization pathways in the DAo in-vivo. Hence, it was our aim to test if the extent of retrograde flow could be estimated by routine 2D transesophageal echocardiography (TEE). Methods: Forty-eight acute stroke patients were prospectively included and they underwent Doppler examinations of the transition zone between the aortic arch and the DAo using a 20 mm 2D sample volume in longitudinal section at 90-140 degrees Doppler angle during routine TEE. Velocity-time-integrals (VTI) were studied for ante-grade and retrograde velocities and the ratio (VTIratio) was calculated and correlated with the length of retrograde pathlines at that site, which were visualized using 4D flow MRI at 3-Tesla. A receiver operating characteristic (ROC) curve was used to evaluate a threshold value of VTIratio in differentiating large (>= 3 cm) from small (< 3 cm) retrograde flow extent. Results: At the TEE measurement site, the mean VTIratio was 0.53 +/- 0.16 and the mean length of retrograde pathlines reaching back into the aortic arch was 3.1 +/- 1.4 cm. VTIratio was an independent predictor of retrograde pathline length (r = 0.44; p = 0.002). ROC analysis identified a VTIratio threshold value of 0.6012 with a sensitivity of 0.5, a specificity of 0.92, and positive and negative predictive values of 0.84 and 0.68, respectively. Accordingly, 11 (22.91%) patients had a VTIratio cutoff value >= 0.6012 and corresponding retrograde pathline length >= 3 cm in 4D flow MRI. Conclusions: TEE allows predicting the length of retrograde pathlines. Hence, it may offer a cost-effective way to investigate independent predictors of DAo flow reversal in large-scale studies. However, TEE is only of limited value as a screening tool for high retrograde flow in a clinical setting, as only similar to 23% of patients can be spared 4D flow MRI, which remains indispensable for the exact assessment of individual embolization pathways from plaques of the DAo in-vivo. (c) 2015 S. Karger AG, Basel