Direct venous‑to‑arterial communication as a novel mechanism for ectopic embolism following esophageal variceal embolization: A case report

Introduction

Esophageal varices are a common and life-threatening complication of portal hypertension in patients with liver cirrhosis (1). Endovascular embolization, often in combination with transjugular intrahepatic portosystemic shunt (TIPS), is a standard therapeutic approach to reduce variceal bleeding (2,3). Although generally effective, complications such as ectopic embolism may occur, occasionally resulting in catastrophic outcomes including cerebral, renal or mesenteric infarction (4,5); the underlying anatomical basis for such events has not been fully elucidated. In patients with cirrhosis, treatment for ectopic embolism caused by esophageal varices is relatively rare. Within the literature, to the best of our knowledge, there is only 1 case of cerebral embolism (6) and 3 cases of spinal cord embolism (7-9), but the specific cause of embolism is unclear.

To the best of our knowledge, the present case is the first reported case of angiographically confirmed direct venous-to-arterial communication causing ectopic embolism. Traditionally, right-to-left shunting mechanisms-such as pulmonary arteriovenous malformations or intracardiac defects-have been implicated (7,10); however, in several cases, including the present case, such mechanisms are absent (11-14).

Case report

Case presentation

A 57-year-old man with a long-standing history of hepatitis B virus-related cirrhosis (Child-Pugh class B; model for end-stage liver disease score 15) (15) was admitted to The Second Affiliated Hospital of The Third Military Medical University (Chongqing, China) in June 2023, for recurrent upper gastrointestinal bleeding and progressive ascites, which was unresponsive to diuretics. Previous endoscopic therapy with ligation had been performed twice over the past year, with partial but temporary hemostasis.

On admission, the patient was hemodynamically stable. Laboratory investigations revealed anemia (hemoglobin, 82 g/l; reference range, 110-160 g/l), thrombocytopenia (platelets, 55x109/l; reference range, 125-350x109/l), hypoalbuminemia (albumin, 28 g/l; reference range, 35-50 g/l) and elevated total bilirubin (34 µmol/l; reference range, 3-22 µmol/l). Imaging using contrast-enhanced abdominal CT showed marked splenomegaly, large esophageal varices and ascites. After multidisciplinary discussion, the patient underwent elective TIPS combined with embolization of esophageal varices.

Imaging and interventions

The TIPS procedure was performed in June 2023, under local anesthesia via a right internal jugular approach. Puncture of the left portal vein branch was achieved via the middle hepatic vein. Splenic venography revealed large, tortuous esophageal varices. After balloon dilatation of the puncture channel (Cook 7x8 mm), an 8x80 mm GORE VIATORR stent graft was placed.

Embolization of the varices was performed through a 4F Cobra catheter by slow injection of a 1:1 mixture of 2 ml tissue adhesive (GLUBRAN2) and 2 ml iodized oil under fluoroscopic control. Pre- and post-TIPS portal pressure gradients were 32 and 17 mmHg, respectively, indicating successful decompression. At ~24 h post-surgery, the patient developed sudden bilateral vision loss and lower limb weakness (grade III muscle strength bilaterally). Magnetic resonance angiography showed embolic occlusion of branches of the middle cerebral artery. Emergent neuroimaging including non-contrast CT and diffusion-weighted MRI revealed multiple acute infarctions in the bilateral frontal lobe, parietal lobe, occipital lobe, temporal lobe, left thalamus and cerebellar hemisphere (Fig. 1A-E).

Figure 1 Multimodal imaging evaluation revealing acute cerebral infarction. (A) Axial head CTA demonstrates spotty and nodular high-density filling of the sclerosing agent within the distal M1 segments of the bilateral MCAs. (B) Head CTA maximum intensity projection reveals cast-like high-density filling in the distal M1 segments of the bilateral MCAs. (C) Brain MRI (DWI, b=800) shows multiple patchy hyperintense lesions in the right frontal lobe and bilateral parietal lobes. (D) Brain MRI DWI (b=800) displays multiple patchy hyperintense lesions in the right temporo-occipital region and the left temporal lobe. (E) Head CTA volume rendering depicts the abrupt cutoff of the distal M1 segments of the bilateral MCAs, accompanied by sparse and reduced distal branching. CTA, CT angiography; MCA, middle cerebral artery; DWI, diffusion-weighted imaging. (A, B and E) Arrows refer to the positions filled with sclerosing agents in the cerebral arteries. (C and D) Arrows refer to the part of the cerebral infarction caused by arterial blockage.

To identify the embolic source, further evaluation was conducted. Echocardiography excluded patent foramen ovale or intracardiac thrombus (Fig. 2C). Additionally, no arteriovenous malformations or pulmonary embolism was found on pulmonary CT angiography (Fig. 2B).

Figure 2 Intraoperative angiography demonstrated direct drainage from the esophageal variceal plexus to the left heart and ascending aorta, exclusion of conventional shunts and underlying abdominal pathology. (A) Sequential fluoroscopic images obtained during the procedure reveal the abnormal vascular pathway in this single patient. Contrast medium injected into the esophageal variceal plexus drains directly into the left heart and subsequently fills the ascending aorta (indicated by arrows), completely bypassing the pulmonary circulation. This rare anatomical variant provided the direct conduit for the embolic material to enter the systemic arterial circulation. (B) Pulmonary CT angiography shows no evidence of pulmonary arteriovenous malformations or pulmonary embolism, ruling out intrapulmonary shunting. (C) Echocardiography reveals normal cardiac chambers with no signs of patent foramen ovale or intracardiac thrombus, excluding intracardiac shunting sources. (D) Contrast-enhanced abdominal CT scan demonstrates marked splenomegaly, extensive esophageal varices and ascites, confirming the background of decompensated cirrhosis and portal hypertension.

Notably, retrospective analysis of fluoroscopic angiography demonstrated direct drainage from the esophageal variceal plexus to the left atrium and ascending aorta, bypassing the pulmonary circulation (Fig. 2A and D and Video S1). This anatomical variant likely accounted for the cerebral embolism.

Due to the recent hemorrhagic history, anticoagulation was withheld, and the patient was managed supportively with neuroprotective agents (0.25 g citicoline once daily for 5 days). Over 2 weeks, bilateral visual acuity markedly improved, and motor function partially recovered. At the most recent follow-up, the patient remained clinically stable with normal mental status and appetite. He reported no recurrence of gastrointestinal bleeding (hematemesis or melena), nausea, vomiting, abdominal pain or ascites.

Discussion

The present case represents a novel mechanism of ectopic embolism in the setting of esophageal variceal embolization. To the best of our knowledge, the present case is the first reported case of angiographically confirmed direct venous-to-arterial communication causing ectopic embolism. Traditionally, right-to-left shunting via patent foramen ovale or pulmonary arteriovenous fistulas has been considered necessary for systemic embolization following venous embolization procedures (16-18). However, in the present case, such conventional shunts were definitively ruled out.

Instead, angiography revealed a rare and direct venous drainage route from the esophageal variceal plexus to the systemic circulation via the left heart, presumably through pathological dilation of small bronchial or mediastinal collaterals (19,20). To the best of our knowledge, this anatomic variant has not been previously described in the literature, in the context of post-embolization cerebral infarction (16).

A similar case of spinal cord infarction after sclerotherapy was reported by Seidman et al (7) in 1984, but no vascular mechanism was identified. Other studies postulated that the patent foramen ovale may allow embolic material into the cerebral circulation during TIPS, but in the absence of identifiable shunts, the mechanism remained speculative (21-25). The present case confirms the hypothesis of an alternative, direct venous-to-arterial conduit.

Due to the difficulty of detecting this vascular pathway with preoperative routine vascular CT, it is recommended to extend the display time and fully understand its flow direction in gastric coronary angiography during TIPS surgery, especially paying attention to whether the heart and aortic circulatory system are visible. From the perspective of surgical safety, if direct esophageal venous to the systemic arterial communication is found during surgery, it is recommended to avoid using liquid embolic agents due to their inherent migration risk (26,27). Solid embolic agents such as coils or embolization are unlikely to penetrate small caliber blood vessels and may be a safer option, particularly when imaging suspicion or abnormal communication is observed prior to embolization (28,29).

In conclusion, the present case highlights a previously unreported cause of systemic embolization following esophageal variceal embolization; direct venous communication between the esophageal variceal plexus and the left heart/ascending aorta. If the cardiac and aortic circulatory systems are found to be visualized during gastric coronary angiography during TIPS surgery, it is recommended to use large-diameter or solid embolic materials such as coils, which may prevent potentially life-threatening ectopic embolic events.

Supplementary Material

Dynamic angiography of the present case. This video demonstrates the direct vascular communication between the esophageal variceal plexus and the left heart/ascending aorta during the transjugular intrahepatic portosystemic shunt procedure, which corresponds to the sequential images shown in Fig. 2A.

Supplementary data.

Acknowledgements

Not applicable.

Funding

Funding: The authors declare that financial support was received for the research, authorship and publication of this article. This study was funded by the General Project of Chongqing Science and Health Joint Medical Research Project (grant no. 2024MSXM081), the Science and Technology Research Project of Chongqing Education Commission (grant no. KJQN202302828), the 2023 Chongqing Nan'an District Science and Health Union Public Medical Research Project (grant no. 2023-05), the Open Research Project of the Chongqing Key Laboratory for Occupational Disease Prevention and Poisoning Treatment in 2021 (grant no. 2021ZYBKF07), the Chongqing Pharmaceutical Vocational Education Group General Project (grant no. CQZJ202352), the General Project of the Incubation Fund within The First Affiliated Hospital of Chongqing Medical and pharmaceutical College (grant no. 2022-2023MS02) and the 2023 Chongqing Nan'an District Public Health Key Specialty (Disease Prevention and Control) Construction Project.

Availability of data and materials

The data generated in the present study may be requested from the corresponding author.

Authors' contributions

YL and ZX contributed to designing the study and performed the surgery. YK obtained the medical images. TY advised on patient treatment and analyzed patient data. ZX and YK confirm the authenticity of all the raw data. All authors have read and approved the final manuscript.

Ethics approval and consent to participate

The Ethics Committee of the Second Affiliated Hospital of the Third Military Medical University (Chongqing, China) exempted the present study from ethical approval. The participant provided written informed consent to participate in this study.

Patient consent for publication

Written informed consent was obtained from the patient for the publication of clinical details and any accompanying images.

Competing interests

The authors declare that they have no competing interests.

References