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Two unique systemic venous connections of levoatriocardinal vein without intracardiac anomalies

Published online by Cambridge University Press:  17 December 2025

Soo Jung Park,
Yoo Jin Jung and
Jae Gun KwakOpen the ORCID record for Jae Gun Kwak[Opens in a new window]
Soo Jung Park
Affiliation:
Department of Thoracic and Cardiovascular Surgery, Kyungpook National University Hospital, Jung-gu, Daegu, South Korea
Yoo Jin Jung
Affiliation:
Department of Thoracic and Cardiovascular Surgery, Seoul National University Children’s Hospital, Jongno-gu, Seoul, South Korea
Jae Gun Kwak*
Affiliation:
Department of Thoracic and Cardiovascular Surgery, Seoul National University Children’s Hospital, Jongno-gu, Seoul, South Korea
*
Corresponding author: Jae Gun Kwak; Email: switch.surgeon@gmail.com
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Abstract

Levoatriocardinal vein is a rare venous anomaly occasionally presenting as a bidirectional shunt in structurally normal hearts. We describe two unique systemic connections of levoatriocardinal vein without intracardiac defects, one causing paradoxical embolism via the hemiazygos vein, and the other draining from the left jugular vein to the pulmonary vein, requiring surgical correction to preserve cerebral venous return.

Keywords

Levoatriocardinal veinsystemic veindrainageparadoxical embolism

Information

Type
Case Report
Information
Cardiology in the Young , Volume 36 , Issue 1 , January 2026, pp. 206 - 209
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Copyright
© The Author(s), 2025. Published by Cambridge University Press

Case report

Case 1

A 23-year-old male presented with hemiplegia due to cerebral embolic infarctions, which recurred despite warfarin therapy. No intracardiac shunt or arrhythmia was detected. CT angiography revealed an enlarged levoatriocardinal vein connecting the left upper pulmonary vein to both the hemiazygos and intercostal veins, forming a venous plexus with the azygos system (Figure 1).

Figure 1.

Case 1: 23-year-old male. Pre-operative axial CT angiography ( a ) with three-dimensional reconstructed images ( b , c ). Images showing two systemic connnection of LACV connected to the LUPV (asterisk), represented by numbers, with one pathway labelled “1” which is connected to hemiazygos vein cranially and the other labelled “2” which is connected to intercostal vein caudally. Engorged intercostal vein made a venous plexus (arrow) cross the vertebral body continued to the azygos vein. Post-operative three-dimensional reconstructed CT image ( d ) represented division state of anmalous connection between LACV and LUPV. LACV = levo atriocardinal vein; LUPV = left upper pulmonary vein.

Given the complexity and calibre of the vessels, percutaneous closure was not suitable. A left posterolateral thoracotomy was performed. The anomalous venous connections were identified and carefully ligated at both the hemiazygos and intercostal veins. Care was taken to avoid residual blind pouches that might promote thrombus formation.

The patient recovered without complications. Post-operative CT confirmed no residual anomalous venous communication (Figure 1d). A bubble contrast echocardiogram revealed no residual right-to-left shunt. After surgical correction of the anomalous pathway, the patient’s antithrombotic regimen was changed from warfarin to clopidogrel, as long-term anticoagulation was deemed less necessary once the paradoxical embolic source had been addressed. No further embolic events occurred, and rehabilitation continued for hemiplegia.

This case highlights a rare variant of levoatriocardinal vein with dual systemic connections in the absence of intracardiac shunt. Recognition and complete surgical interruption of such anomalous pathways are crucial in patients with unexplained embolic events, particularly when conventional thromboembolic risk factors are absent.

Case 2

A 5-year-old male was diagnosed with glaucoma. Pre-operative chest X-ray showed a bulge near the left aortic interface. CT angiography revealed a levoatriocardinal vein connecting the left internal jugular vein to the left lower pulmonary vein (Figure 2A –C), with absence of the left brachiocephalic vein. The missing brachiocephalic vein raised concern that dividing the levoatriocardinal vein might compromise cerebral venous return from the left internal jugular vein.

Figure 2.

Case 2: 5-year-old male. Coronal CT angiography ( a ) with three-dimensional reconstructed images ( b , c ). ( a ) and ( b ) The connection of torturous LACV between LLPV (asterisk) and left IJV (arrow). Absent left BCV was shown by dashed line box in ( c ). Post-operative three-dimensional reconstructed CT image ( d ) showed reconstructed state of LACV (black star), resembling left BCV which connected left IJV to SVC. BCV = brachiocephalic vein; IJV = internal jugular vein; LACV = levo atriocardinal vein; LUPV = left upper pulmonary vein; SVC = superior vena cava.

To assess cerebral venous drainage, brain MR venography (Figure 3) was performed and revealed that the majority of cranial venous outflow drained through the left internal jugular vein. Given the absence of the brachiocephalic vein, redirection of the levoatriocardinal vein into the systemic venous system was deemed necessary to preserve cerebral drainage.

Figure 3.

Brain MR venography: (coronal view), brain MR brain venography demonstrated occlusion of the right internal jugular vein with multiple collateral vessels, and the right sigmoid sinus appeared aplastic.

The levoatriocardinal vein was surgically divided from the left lower pulmonary vein, and its proximal end was redirected and anastomosed to the right superior vena cava, reconstructing the functional equivalent of a left brachiocephalic vein. Post-operative CT showed a patent anastomosis, although slight compression by the ascending aorta was noted. Although the anastomosis was performed between native tissue (levoatriocardinal vein and right atrium), there was a discrepancy in size, and the reconstructed vessel coursed across the ascending aorta, which could result in compression from the aorta. These two factors could potentially interfere with maintaining a smooth laminar flow. Therefore, to prevent thrombus formation, aspirin was administered at a dose of approximately 5 mg/kg for about 2 months post-operatively as thromboprophylaxis.

The patient recovered without signs of cerebral venous insufficiency or embolic complications.

This case illustrates an unusual levoatriocardinal vein draining from the left internal jugular vein to the pulmonary venous system in the absence of a left brachiocephalic vein. Surgical redirection of the levoatriocardinal vein successfully restored systemic venous return and prevented cerebral congestion, with pre-operative MR venography playing a critical role in planning the reconstruction strategy.

Discussion

Levoatriocardinal vein is a rare vascular anomaly involving abnormal venous communication between the pulmonary and systemic circulations. While most commonly associated with left-sided obstructive lesions, such as hypoplastic left heart syndrome, levoatriocardinal vein can also occur in structurally normal hearts. The connection typically drains into the left brachiocephalic vein or right superior vena cava. Reference Bernstein, Moore and Stanger1,Reference Tosun, Saygı and Kasar2 The levoatriocardinal vein, initially described in 1926 by McIntosh et al., represents an anomalous venous channel between the pulmonary and systemic venous systems. Reference McIntosh3 Embryologically, the levoatriocardinal vein represents a persistent channel between the pulmonary venous plexus and the cardinal venous system. The left brachiocephalic vein normally arises from a transverse anastomosis between the right and left anterior cardinal veins; failure of this anastomosis results in its absence. In the largest case series with a literature review by Bernstein et al., drainage patterns were most commonly to the left brachiocephalic vein (48%) or right superior vena cava (36%). Reference Bernstein, Moore and Stanger1 A subsequent study by Tosun et al. reported similar patterns in 11 patients, with 64% draining to the right superior vena cava and 36% to the left brachiocephalic vein. Reference Tosun, Saygı and Kasar2

The clinical presentation of levoatriocardinal vein varies from asymptomatic to severe thromboembolic events. Such complications can have serious consequences, including ischaemic stroke, myocardial infarction, or peripheral embolism. Reference Karangelis, Avramidis and Mousiama4 Levoatriocardinal vein is a persistent pulmonary–systemic venous channel and may show bidirectional shunting depending on relative pressures, whereas Partial anomalous pulmonary venous connection—including Scimitar syndrome—results from failure of complete incorporation of the pulmonary venous plexus into the left atrium and consistently drains pulmonary venous blood into the systemic venous circulation. However, due to its rarity and often non-specific findings, levoatriocardinal vein is frequently overlooked or misdiagnosed. Reference Agarwal, Mahani and Lu5 CT angiography and MR venography are essential tools for defining anatomic relationships and planning appropriate intervention.

In our first case, the levoatriocardinal vein drained from the left upper pulmonary vein to both the hemiazygos and intercostal veins, forming a venous plexus, and was associated with systemic embolism despite anticoagulation. Surgical interruption of both abnormal connections led to resolution of embolic events. This case highlights the need to consider extracardiac right-to-left shunts like levoatriocardinal vein in patients with paradoxical embolism and no evident intracardiac source. After interruption of the anomalous channel, the embolic risk was considered reduced, and antiplatelet therapy was chosen in line with secondary stroke prevention guidelines. Warfarin was therefore replaced with clopidogrel.

The second case involved a child with an levoatriocardinal vein draining from the left internal jugular vein to the left lower pulmonary vein, in the absence of a left brachiocephalic vein. Pre-operative MR venography showed dominant cerebral venous return through the left internal jugular vein. To preserve this outflow, the levoatriocardinal vein was redirected to the right superior vena cava, effectively reconstructing the left brachiocephalic vein. Post-operative imaging confirmed patency, and the patient was clinically stable and asymptomatic.

The complete interruption of shunt lesions and the successful application of vascular reconstruction strategies, guided by comprehensive understanding of levoatriocardinal vein variants and precise anatomical delineation through imaging, are fundamental to achieving favourable patient outcomes.

Financial support

This study was supported by a Seoul national University Research Grant (No. 800-20230598).

Competing interests

The authors have no conflicts of interest to disclose.

Ethical standard

This case report was approved by the Institutional Review Board (IRB) of Seoul National University Hospital (IRB number: H- 2308-003-1455; IRB approval date: August 4th, 2023), and the requirement for informed consent was waived.

References

Bernstein, HS, Moore, P, Stanger, P, et al. The levoatriocardinal vein: morphology and echocardiographic identification of the pulmonary-systemic connection. J Am Coll Cardiol 1995; 26: 995–1001.CrossRefGoogle ScholarPubMed
Tosun, Ö., Saygı, M, Kasar, T, et al. A rare pathology: levoatriocardinal vein. Turk Kardiyol Dern Ars 2016; 44: 315–319.Google ScholarPubMed
McIntosh, CA. Cor biatriatum triloculare. Am Heart J 1926; 1: 735–744.CrossRefGoogle Scholar
Karangelis, D, Avramidis, D, Mousiama, T, et al. Levoatriocardinal vein: a rarely recognized cause of recurrent cardiac and cerebral thromboembolic events. Can J Cardiol 2020; 36: 589.e9–589.e11.Google Scholar
Agarwal, PP, Mahani, MG, Lu, JC, et al. Levoatriocardinal vein and mimics: spectrum of imaging findings. AJR Am J Roentgenol 2015; 205: W162–W171.CrossRefGoogle ScholarPubMed
Figure 0

Figure 1.Case 1: 23-year-old male. Pre-operative axial CT angiography (a) with three-dimensional reconstructed images (b,c). Images showing two systemic connnection of LACV connected to the LUPV (asterisk), represented by numbers, with one pathway labelled “1” which is connected to hemiazygos vein cranially and the other labelled “2” which is connected to intercostal vein caudally. Engorged intercostal vein made a venous plexus (arrow) cross the vertebral body continued to the azygos vein. Post-operative three-dimensional reconstructed CT image (d) represented division state of anmalous connection between LACV and LUPV. LACV = levo atriocardinal vein; LUPV = left upper pulmonary vein.

Figure 1

Figure 2.Case 2: 5-year-old male. Coronal CT angiography (a) with three-dimensional reconstructed images (b,c). (a) and (b) The connection of torturous LACV between LLPV (asterisk) and left IJV (arrow). Absent left BCV was shown by dashed line box in (c). Post-operative three-dimensional reconstructed CT image (d) showed reconstructed state of LACV (black star), resembling left BCV which connected left IJV to SVC. BCV = brachiocephalic vein; IJV = internal jugular vein; LACV = levo atriocardinal vein; LUPV = left upper pulmonary vein; SVC = superior vena cava.

Figure 2

Figure 3.Brain MR venography: (coronal view), brain MR brain venography demonstrated occlusion of the right internal jugular vein with multiple collateral vessels, and the right sigmoid sinus appeared aplastic.