Supplementary Material for: Orientation of the atrial septum to the inferior vena cava may contribute to the persistent patency of the foramen ovale

Purpose: There is growing evidence that paradoxical embolism through patent foramen ovale (PFO) is a cause for cryptogenic stroke. However, it is still unclear why the foramen ovale fails to close after birth. We studied whether the 3D relations between the atrial septum and the inferior vena cava (IVC) are associated with PFO. Methods: We recruited 30 patients (18-49 years) with a first-ever cryptogenic stroke and 30 age- and sex-matched stroke-free controls. Using cardiac magnetic resonance (CMR), an approach to evaluate the 3D relations between the atrial septum and the IVC was developed. The presence of interatrial right-to-left shunt was evaluated with transesophageal echocardiography (TEE) in patients and transcranial Doppler in controls. Results: Of 30 patients, 29 underwent successful TEE, of which 12 (41%) had a shunt. Patients with a shunt had a greater mean 3D angle (γ) between the atrial septal plane and the vector from the orifice of the IVC to the middle of the atrial septum compared with patients without a shunt (45±9° vs. 36±8°, p=0.017). Of 30 controls, 12 (40%) had a shunt and a greater mean γ compared with controls without a shunt (47±8° vs. 37±10°, p=0.007). In a pooled analysis, 24 (41%) of 59 subjects with a shunt had a mean γ of 46±9° compared with subjects without a shunt of 37±9° (p<0.001). Conclusions: More perpendicular orientation of the atrial septal plane to the orifice of the IVC is associated with PFO, possibly by directing the IVC flow to PFO.研究背景与目的：越来越多的证据表明，经卵圆孔未闭（patent foramen ovale, PFO）引发的反常栓塞是隐源性卒中（cryptogenic stroke）的致病诱因之一，但目前仍未明确卵圆孔在出生后未能闭合的具体机制。本研究旨在探讨房间隔（atrial septum）与下腔静脉（inferior vena cava, IVC）之间的三维空间关系是否与卵圆孔未闭存在关联。 研究方法：本研究纳入30例年龄介于18至49岁的首发隐源性卒中患者，以及30例年龄与性别相匹配的无卒中对照受试者。通过心脏磁共振成像（cardiac magnetic resonance, CMR）技术，建立了一套用于评估房间隔与下腔静脉三维空间关系的分析方案。针对患者，采用经食管超声心动图（transesophageal echocardiography, TEE）检测心房水平右向左分流情况；针对对照受试者，则采用经颅多普勒（transcranial Doppler）完成该项评估。 研究结果：30例患者中，29例成功完成经食管超声心动图检查，其中12例（占比达41%）检测到右向左分流。存在分流的患者，其房间隔平面与下腔静脉开口至房间隔中点的矢量之间的平均三维夹角（γ）显著高于无分流患者（45±9° 与 36±8°相比，p=0.017）。30例对照受试者中，12例（占比达40%）检测到右向左分流，存在分流的对照受试者的平均三维夹角（γ）同样显著高于无分流的对照受试者（47±8° 与 37±10°相比，p=0.007）。合并分析结果显示，59例存在右向左分流的受试者中，24例（占比达41%）的平均三维夹角（γ）为46±9°，而无分流受试者的平均三维夹角为37±9°（p<0.001）。 研究结论：房间隔平面与下腔静脉开口的垂直取向程度越高，与卵圆孔未闭的发生呈显著相关，该关联可能是由于下腔静脉血流更易定向流向卵圆孔未闭部位所致。