Matsuoka Hideki
Department of Cerebrovascular Division, National Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan.
Brain Nerve. 2008 Oct;60(10):1134-43.
The presence of right-to-left shunt (RLS), which can result in paradoxical brain embolism, is an important etiology of ischemic stroke especially in young adults. However, the characteristic features of RLS and paradoxical brain embolism have not been recognized in detail, especially in Japan. Patent foramen ovale (PFO) and pulmonary arterio-venous fistula are the most important causes of RLS. According to the registered clinical data of 7,245 acute stroke patients obtained by the Strategies Against Stroke Study for Young Adults in Japan (SASSY-Japan), PFO is more frequent in young patients (n = 1,584) than in old patients (n = 5,661) (1.2% vs. 0.7%, p = 0.07). However, the prevalence of PFO in the study was considerably lower than that in previous studies. The low prevalence of PFO in this study was probably due to the limited number of subjects who underwent transesophageal echocardiography (TEE) or other examinations for the detection of RLS. Currently, the golden standard for detecting RLS is contrast-enhanced TEE. Developing a standard method of TEE is very important for the accurate diagnosis of RLS. In recent years, transcranial Doppler ultrasound has been reported to be a noninvasive and useful method for detecting RLS. Ultrasonography is considered to be a most useful method for evaluating venous thrombi, as the source of the embolism. It is recommended that these examinations be carried out immediately after the onset of the stroke. In order to prevent ischemic strokes in patients with RLS, treatment should be provided based on coexisting factors. Patients with other risk factors, such as venous thrombus and a cardiac source of embolism, should be administered anticoagulation therapy and the prothrombin time--international normalized ratio should be closely monitored. The PICCS confirmed that there was no difference in the recurrence rate of embolism between patients who were administered anticoagulation therapy and these administered aspirin therapy, in patients with no other risk factors. Therefore, patients with no other risk factors may be administered antiplatelet therapy.
右向左分流（RLS）可导致反常脑栓塞，是缺血性卒中尤其是年轻成人缺血性卒中的重要病因。然而，RLS和反常脑栓塞的特征尚未得到详细认识，尤其是在日本。卵圆孔未闭（PFO）和肺动静脉瘘是RLS的最重要原因。根据日本针对年轻成人的卒中研究策略（SASSY-Japan）获得的7245例急性卒中患者的注册临床数据，年轻患者（n = 1584）中PFO的发生率高于老年患者（n = 5661）（1.2%对0.7%，p = 0.07）。然而，该研究中PFO的患病率明显低于先前研究。本研究中PFO患病率低可能是由于接受经食管超声心动图（TEE）或其他检测RLS检查的受试者数量有限。目前，检测RLS的金标准是对比增强TEE。开发TEE的标准方法对于准确诊断RLS非常重要。近年来，经颅多普勒超声已被报道为检测RLS的一种无创且有用的方法。超声检查被认为是评估作为栓塞来源的静脉血栓的最有用方法。建议在卒中发作后立即进行这些检查。为预防RLS患者发生缺血性卒中，应根据并存因素进行治疗。有其他危险因素（如静脉血栓和心脏栓塞源）的患者应接受抗凝治疗，并应密切监测凝血酶原时间-国际标准化比值。PICCS证实，在无其他危险因素的患者中，接受抗凝治疗的患者与接受阿司匹林治疗的患者之间栓塞复发率无差异。因此，无其他危险因素的患者可接受抗血小板治疗。
