Recurrent Ischemic Stroke Caused by a Residual PFO Shunt After Surgical Repair: Three‐Dimensional Transesophageal Echocardiography‐Guided Localization and Transcatheter Closure

Abstract

Residual shunting after surgical PFO closure may cause recurrent paradoxical embolism. Three‐dimensional transesophageal echocardiography combined with microbubble testing and multiplanar reconstruction enabled precise localization of an elusive residual shunt and guided successful transcatheter closure.

1.

A 50‐year‐old man who had undergone isolated surgical closure of a patent foramen ovale (PFO) with mattress suturing for a previous paradoxical embolic stroke five years earlier presented with rotational vertigo and was diagnosed with acute cerebral infarction in the right occipital lobe. Evaluation for alternative stroke etiologies, including carotid ultrasonography, Holter electrocardiographic monitoring, and laboratory testing for thrombophilia, revealed no vulnerable atherosclerotic disease, atrial fibrillation, or hypercoagulable condition. Lower‐extremity venous ultrasonography showed no evidence of deep vein thrombosis. Although a venous thrombotic source was not identified, the Risk of Paradoxical Embolism (RoPE) score was 6, and paradoxical embolism through the residual PFO shunt was considered the most likely cause of recurrent cerebral infarction.

Although the bubble testing at rest showed no right‐to‐left shunt (RLS) on transthoracic echocardiography (TTE), the testing during Valsalva maneuver (VM) demonstrated a large RLS. The Bubble study by transesophageal echocardiography (TEE) was performed as follows. Agitated saline contrast, prepared by mixing 8 mL saline, 1 mL air, and 1 mL blood, was injected through a 20‐gauge catheter placed in the right antecubital vein. Because the residual shunt could not be localized using conventional imaging, multiple contrast injections were performed at rest and during VM. The VM was maintained for approximately 10 seconds with concomitant abdominal compression and released when the right atrium became densely opacified. Microbubbles appeared in left atrium (LA) within three cardiac cycles after right atrial opacification, consistent with an intracardiac RLS. Shunt severity was graded according to the number of microbubbles appearing in LA (grade 1, 1–5; grade 2, 6–19; grade 3, ≥20 microbubbles). TEE bubble testing demonstrated a grade 2 RLS in LA during VM, but the exact origin of the RLS could not be identified. Real‐time 3D zoom imaging from the left atrial perspective, combined with real‐time multiplanar reconstruction, demonstrated a linear microbubble stream arising slightly posterosuperior to the fossa ovalis and localized the presumed origin of the residual RLS (Figure 1 and Supplemental Movie 1), likely corresponding to a small residual defect near the superior vena cava rim suture line. Based on these findings, recurrent cerebral embolism due to residual PFO shunting was diagnosed, and percutaneous PFO closure was planned.

FIGURE 1.

Multiplanar reconstruction of 3D‐TEE for microbubbles visualized from the left atrial perspective demonstrated a linear stream (dotted line) aligned coaxially, confirming a right‐to‐left shunt (RLS) across the interatrial septum and localizing its origin (white arrowhead) slightly posterosuperior to the fossa ovalis. 3D‐TEE, three‐dimensional transesophageal echocardiography; LA, left atrium; RUPV, right upper pulmonary vein.

The procedure was performed via the femoral venous approach under fluoroscopic and 3D‐TEE guidance using an 8.5‐Fr long sheath. Because the residual communication could not be crossed under conventional fluoroscopic and two‐dimensional TEE guidance, real‐time 3D‐TEE from the right atrial perspective was used to guide targeted probing of the region slightly posterior to the superior central portion of the fossa ovalis (Figure 2 and Supplemental Movie 2, upper panel). The residual communication was successfully crossed using a multipurpose catheter and a 0.035‐inch straight guidewire. Balloon sizing was not performed because the communication was extremely small. An 18‐mm AMPLATZER Talisman PFO Occluder (Abbott, Abbott Park, IL, USA) was selected as the smallest available PFO occluder and was considered sufficient to cover the pinpoint residual communication and adjacent septal tissue. Intraprocedural 3D‐TEE confirmed appropriate device positioning without interference with adjacent structures, including the superior vena cava rim. Postprocedural bubble testing was negative even during VM (Figure 3 and Supplemental Movie 2, lower panel). Single antiplatelet therapy with aspirin was continued during the periprocedural period and after device closure. Follow‐up TTE with bubble testing performed 6 months after the procedure demonstrated complete disappearance of the residual RLS. No recurrent cerebral ischemic events were observed during the 6‐month follow‐up period.

FIGURE 2.

Intraprocedural 3D‐TEE frontal views from the right atrial perspective illustrating successful guidewire navigation and crossing of the defect (yellow arrowhead), along with a corresponding schematic image. 3D‐TEE, three‐dimensional transesophageal echocardiography; SVC, superior vena cava; RA, right atrium; Ao, aorta.

FIGURE 3.

Post‐deployment 3D‐TEE images from both atrial perspectives confirming appropriate positioning of the occluder device. Post‐procedural bubble testing demonstrating complete disappearance of the RLS. 3D‐TEE, three‐dimensional transesophageal echocardiography; LA, left atrium; RA, right atrium.

Transcatheter closure has been reported to be a feasible and relatively safe treatment option for significant residual shunts following surgical closure of an atrial septal defect [1]. Although residual right‐to‐left shunting after surgical PFO closure is extremely rare, it may result in recurrent cerebral embolic events [2]. Previous reports have emphasized that the PFO tunnel can be involved in embolic mechanisms, either as a conduit for paradoxical embolism or as a potential site of thrombus formation [3]. Therefore, even a small residual interatrial communication after surgical closure may be clinically relevant when recurrent embolic events occur. In the present case, 3D‐TEE‐guided bubble testing enabled precise localization of the residual shunt and facilitated successful transcatheter closure. Currently, transcatheter closure is the standard treatment for PFO‐associated stroke [4], and isolated surgical PFO closure is rarely performed. Nevertheless, PFO or small atrial septal defects are still occasionally closed surgically during concomitant cardiac procedures, such as valve surgery. Consequently, residual interatrial shunts may still be encountered in contemporary practice and should be recognized as a potential source of recurrent paradoxical embolism. When residual shunting is suspected but difficult to localize using conventional imaging, 3D‐TEE with bubble testing and multiplanar reconstruction may provide incremental value by identifying the presumed shunt origin and guiding catheter‐based intervention.

Funding

The authors have nothing to report.

Ethics Statement

Institutional Review Board approval was waived for this single case report in accordance with institutional policy.

Consent

Written informed consent was obtained from the patient for publication of this case report and accompanying images.

Conflicts of Interest

The authors declare no conflicts of interest.

Supporting information

Supporting Information: echo70548‐supp‐0001‐Movie 1.mp4

Supporting Information: echo70548‐supp‐0002‐Movie 2.mp4