Abstract: Objective  To investigate the effects of shunts with different origins detected by contrast-enhanced transesophageal echocardiography (cTEE) on ischemic stroke.
Methods  This study retrospectively enrolled patients hospitalized in the Department of Neurology and the Department of Cardiovascular Medicine at Shenzhen Second People’s Hospital from December 2021 to June 2025, who were confirmed to have a right to left shunt by cTEE. Based on the origin of right to left shunt, patients were divided into three groups: isolated intracardiac shunt group, mixed shunt group (combined intracardiac and intrapulmonary shunt), and isolated intrapulmonary shunt group. The severity of RLS was semi‑quantitatively graded according to the maximum microbubble count in the left atrium on a single cTEE frame, as follows: mild (grade Ⅰ), moderate (grade Ⅱ), and severe (grade Ⅲ). Demographic characteristics, shunt severity, and the incidence of ischemic stroke were compared among the three groups. Furthermore, a multivariate logistic regression model was constructed to explore the association of various factors with the occurrence of ischemic stroke, with its occurrence as the dependent variable.
Results  A total of 286 patients were enrolled in this study, including 40 in the isolated intracardiac shunt group, 127 in the mixed shunt group, and 119 in the isolated intrapulmonary shunt group. The isolated intrapulmonary shunt group was predominantly characterized by mild shunting (71.4%), with a significantly higher proportion than that in the isolated intracardiac shunt group (22.5%, adjusted P＜0.001) and the mixed shunt group (13.4%, adjusted P＜0.001). In contrast, the mixed shunt group had a high proportion of severe shunting, accounting for 51.2%. Multivariate logistic regression analysis revealed that, using the isolated intrapulmonary shunt as the reference, mixed shunt (OR 2.515, 95%CI 1.217-5.197) and isolated intracardiac shunt (OR 2.727, 95%CI 1.107-6.716) were independently and positively associated with the occurrence of stroke. Increased age (OR 1.037, 95%CI 1.013-1.062) and comorbid diabetes mellitus (OR 2.350, 95%CI 1.138-4.854) were also independently associated with a higher risk of ischemic stroke, whereas female sex (OR 0.481, 95%CI 0.257-0.901) was associated with a lower risk of stroke.
Conclusions  The risk of ischemic stroke in patients with isolated intrapulmonary shunt is relatively low; therefore, excessive examination and intervention for this type of shunt should be avoided in clinical practice. The focus of prevention and treatment should revert to the management of conventional cerebrovascular risk factors, including advanced age, sex, diabetes mellitus, and intracardiac shunt.

Key words: Contrast-enhanced transesophageal echocardiography; Right to left shunt; Patent foramen ovale; Intrapulmonary shunt; Ischemic stroke

摘要： 目的 探讨对比增强经食管超声心动图（contrast-enhanced transesophageal echocardiography，cTEE）中发现的不同来源的右向左分流对缺血性卒中的影响。
方法 回顾性纳入2021年12月—2025年6月于深圳市第二人民医院神经内科及心血管内科住院，且经cTEE证实存在右向左分流的患者。根据右向左分流来源将患者分为单纯心内分流组、混合分流组（心内合并肺内分流）和单纯肺内分流组。依据cTEE单帧图像左心房最大微泡计数进行半定量分级：少量（Ⅰ级）、中量（Ⅱ级）及大量（Ⅲ级）。比较三组患者的人口学特征、分流严重程度及缺血性卒中发生情况。以是否发生缺血性卒中为因变量，构建多因素logistic回归模型探讨不同因素与卒中发生的关联。
结果 本研究共纳入286例患者，其中单纯心内分流组40例，混合分流组127例，单纯肺内分流组119例。单纯肺内分流组以少量分流为主（71.4%），其比例显著高于单纯心内分流组（22.5%，P校正＜0.001）和混合分流组（13.4%，P校正＜0.001）；而混合分流组的大量分流占比达51.2%。多因素logistic回归分析显示，以单纯肺内分流为参照，混合分流（OR 2.515，95%CI 1.217～5.197）与单纯心内分流（OR 2.727，95%CI 1.107～6.716）均与较高的卒中发生风险独立正相关；年龄增加（OR 1.037，95%CI 1.013～1.062）及合并糖尿病（OR 2.350，95%CI 1.138～4.854）与缺血性卒中独立正相关；而女性（OR 0.481，95%CI 0.257～0.901）与较低的卒中发生风险相关。
结论 单纯肺内分流人群的缺血性卒中发生风险较低，临床对于此类分流勿过度检查与干预。防治重心应回归至对高龄、性别、糖尿病及心内分流等传统脑血管危险因素的管控。

关键词: 对比增强经食管超声心动图; 右向左分流; 卵圆孔未闭; 肺内分流; 缺血性卒中