Department of Neurology, Stroke and Cerebrovascular Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Int J Stroke. 2013 Dec;8(8):657-62. doi: 10.1111/j.1747-4949.2012.00846.x. Epub 2012 Jul 19.
Paradoxical embolism has been documented as a mechanism of cryptogenic embolic stroke. We investigated the frequency of right-to-left shunt in patients with cryptogenic embolic stroke and evaluated the factors associated with diffusion-weighted imaging (DWI) lesion pattern.
We analyzed data on 157 consecutive patients with acute ischemic stroke because of presumed cryptogenic embolism. Agitated saline transcranial Doppler study was conducted in all patients to detect right-to-left shunt. We evaluated the association of the amount (microemboli <20 vs. ≥20) and activity (spontaneous vs. after Valsalva maneuver only) of right-to-left shunt with diffusion-weighted imaging lesion patterns.
Right-to-left shunt was observed in 96 (61·1%) patients. The multiplicity and distribution of diffusion-weighted imaging lesions did not differ depending on the amount and activity of right-to-left shunt. However, the size of diffusion-weighted imaging lesions differed depending on the amount of right-to-left shunt (P = 0·019). Right-to-left shunt was more frequently observed in patients with small (<1 cm) infarcts than in those with a large infarct (66·7% vs. 45·9%), and most patients with a larger amount of right-to-left shunt were found to have small infarcts on diffusion-weighted imaging (80%). The clinical characteristics, including Framingham stroke risk strategy, did not differ between the groups.
Our results indicate that the amount of right-to-left shunt determines the Diffusion-weighted imaging lesion patterns and suggest that mechanisms of stroke other than paradoxical mechanism may play an important role in patients with large cryptogenic embolic stroke.
反常栓塞已被证实为隐源性栓塞性卒中的发病机制之一。我们调查了隐源性栓塞性卒中患者中右向左分流的频率，并评估了与弥散加权成像（DWI）病变模式相关的因素。
我们分析了 157 例连续的因疑似隐源性栓塞导致急性缺血性卒中患者的数据。所有患者均行激动盐水经颅多普勒超声检查以检测右向左分流。我们评估了右向左分流的量（微栓子＜20 个 vs. ≥20 个）和活性（自发 vs. 仅瓦尔萨尔动作后）与弥散加权成像病变模式的相关性。
96 例（61.1%）患者观察到右向左分流。弥散加权成像病变的多发性和分布与右向左分流的量和活性无关。然而，弥散加权成像病变的大小取决于右向左分流的量（P = 0.019）。与大梗死相比，小梗死（＜1cm）患者更常出现右向左分流（66.7% vs. 45.9%），并且大多数右向左分流量大的患者在弥散加权成像上表现为小梗死（80%）。临床特征，包括弗莱明翰卒中风险策略，在两组之间没有差异。
我们的结果表明，右向左分流的量决定了弥散加权成像的病变模式，并提示除反常机制以外的卒中机制可能在大隐源性栓塞性卒中患者中发挥重要作用。
