Department of Neurology and Neurophysiology, Medical Center, University of Freiburg, Breisacherstr. 64, 79106, Freiburg, Germany.
Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Eur Radiol. 2019 Oct;29(10):5172-5179. doi: 10.1007/s00330-019-06104-z. Epub 2019 Mar 15.
Retrograde blood flow from complex atheroma in the descending aorta (DAo) has only recently been described as a potential mechanism of stroke. However, prevalence of this mechanism in the general population and the exact factors influencing stroke risk are unclear.
One hundred twenty-six consecutively recruited inhabitants of Freiburg, Germany, between 20 and 80 years of age prospectively underwent 3-T MRI. Aortic plaque location and thickness were determined by 3D T1 MRI (1 mm). 4D flow MRI (spatial/temporal resolution 2 mm/20 ms) and dedicated software were used to determine prevalence and extent of flow reversal and potential embolization from DAo plaques. Flow was correlated with baseline characteristics and echocardiographic and MRI parameters (aortic diameter, wall thickness, and pulse wave velocity).
The maximum length of retrograde blood flow connecting the DAo with the left subclavian artery (LSA) increased from 16.1 ± 8.3 mm in 20-29-year-old to 24.7 ± 11.7 mm in 70-80-year-old subjects, correlated with age (r = 0.37; p < 0.001), and was lower in females (p = 0.003). Age was the only independent predictor of increased flow reversal. Complex DAo plaques ≥ 4-mm thickness were found in eight subjects (6.3%) and were connected with the LSA, left common carotid artery, and brachiocephalic trunk in 8 (100%), 1 (12.5%), and 0 (0%) cases, respectively.
Retrograde blood flow from the DAo was very frequent. However, potential retrograde embolization was rare due to the low incidence of complex DAo plaques. The magnitude of flow reversal and prevalence of complex atheroma increased with age. Thus, older patients with aortic atherosclerosis are especially vulnerable to this stroke mechanism.
• 4D flow MRI allows in vivo visualization and quantification of individual and three-dimensional blood flow patterns within the thoracic aorta including retrograde components. • This population-based study showed that blood flow reversal from the proximal descending aorta to the brain-supplying great arteries is very frequent and able to reach all brain territories. The extent of such flow reversal increases with age and with the extent of aortic atherosclerosis. • The combination of blood flow reversal with plaque rupture in the proximal descending aorta constitutes a potential stroke mechanism that should be considered in future trials and in the management of stroke patients in clinical routine.
降主动脉（DAo）内复杂粥样硬化斑块的逆行血流最近才被描述为中风的潜在机制。然而，这种机制在普通人群中的流行程度以及确切影响中风风险的因素尚不清楚。
126 名连续招募的德国弗赖堡居民在 20 至 80 岁之间前瞻性地接受了 3-T MRI 检查。通过 3D T1 MRI（1mm）确定主动脉斑块的位置和厚度。使用 4D 流 MRI（空间/时间分辨率 2mm/20ms）和专用软件来确定 DAo 斑块的血流反转和潜在栓塞的发生率和程度。血流与基线特征以及超声心动图和 MRI 参数（主动脉直径、壁厚度和脉搏波速度）相关联。
连接 DAo 与左锁骨下动脉（LSA）的逆行血流最大长度从 20-29 岁的 16.1±8.3mm 增加到 70-80 岁的 24.7±11.7mm，与年龄相关（r=0.37；p<0.001），女性较低（p=0.003）。年龄是唯一能预测血流反转增加的独立因素。8 名受试者（6.3%）存在≥4mm 厚度的复杂 DAo 斑块，与 LSA、左颈总动脉和头臂干分别有 8（100%）、1（12.5%）和 0（0%）例连接。
来自 DAo 的逆行血流非常频繁。然而，由于复杂的 DAo 斑块发生率较低，潜在的逆行栓塞很少发生。血流反转的幅度和复杂粥样硬化斑块的发生率随着年龄的增长而增加。因此，主动脉粥样硬化的老年患者尤其容易受到这种中风机制的影响。
4D 流 MRI 可在体内可视化和量化胸主动脉内的个体和三维血流模式，包括逆行成分。
这项基于人群的研究表明，来自近端降主动脉至大脑供血大动脉的血流反转非常频繁，能够到达所有大脑区域。这种血流反转的程度随年龄和主动脉粥样硬化的程度而增加。
近端降主动脉内血流反转与斑块破裂的结合构成了一种潜在的中风机制，应在未来的试验中考虑，并在临床常规中对中风患者进行管理。
