
==== Front
Acute Med Surg
Acute Med Surg
10.1002/(ISSN)2052-8817
AMS2
Acute Medicine & Surgery
2052-8817
John Wiley and Sons Inc. Hoboken

10.1002/ams2.70007
AMS270007
AMS-2024-0058.R2
Case Report
Case Report
A case of right atrial thrombus in the Chiari network after blunt cardiac rupture
Right atrial thrombus in the Chiari network
Oishi et al.
Oishi Takahiro https://orcid.org/0009-0000-9269-6401
1 t.oishi.0516@gmail.com

Tamagaki Keisuke 2
Maruyama Shuhei https://orcid.org/0009-0009-9836-2870
1
Kanayama Shuji 1
Wada Daiki https://orcid.org/0000-0002-3404-9924
1
Yoshihara Tomoyuki 1
Saito Fukuki 1
Yoshiya Kazuhisa 1
Nakamori Yasushi 1
Kuwagata Yasuyuki 2
1 Department of Emergency and Critical Care Medicine Kansai Medical University General Medical Center Osaka Japan
2 Department of Emergency and Critical Care Medicine Kansai Medical University Osaka Japan
* Correspondence
Takahiro Oishi, Department of Emergency and Critical Care Medicine, Kansai Medical University General Medical Center, 10‐15 Fumizonocho, Moriguchi, Osaka 570‐8507, Japan.
Email: t.oishi.0516@gmail.com

23 9 2024
Jan-Dec 2024
11 1 10.1002/ams2.v11.1 e7000731 8 2024
29 2 2024
11 9 2024
© 2024 The Author(s). Acute Medicine & Surgery published by John Wiley & Sons Australia, Ltd on behalf of Japanese Association for Acute Medicine.
https://creativecommons.org/licenses/by-nc/4.0/ This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Abstract

Background

The Chiari network mostly causes no symptoms but may occasionally be involved in thrombus formation in the right atrium. We present a case of right atrial thrombus discovered in the postoperative course of blunt cardiac rupture.

Case Presentation

A 19‐year‐old female injured in a motor vehicle accident was transported to the hospital in a state of shock. Echocardiography revealed pericardial effusion. Cardiopulmonary arrest was imminent, so a clamshell thoracotomy was performed. A laceration at the right atrial junction of the superior vena cava was observed and sutured. Echocardiography on post‐injury day 6 showed a floating thrombus in the right atrium. Anticoagulation therapy was started, the thrombus was reduced, and the patient was discharged on day 27 without sequelae. Six months later, echocardiography showed a filamentous structure and the presence of the Chiari network.

Conclusion

Right intra‐atrial thrombi are rare and may warrant a search of the Chiari network in conditions where hypercoagulation is anticipated.

The Chiari network mostly causes no symptoms but may occasionally be involved in thrombus formation in the right atrium. The present report is the first that we could find in which the presence of a Chiari network was diagnosed after a course of treatment for trauma.

anticoagulation therapy
blunt cardiac rupture
Chiari network
clamshell thoracotomy
right atrial thrombus
source-schema-version-number2.0
cover-dateJanuary/December 2024
details-of-publishers-convertorConverter:WILEY_ML3GV2_TO_JATSPMC version:6.4.8 mode:remove_FC converted:23.09.2024
Oishi T , Tamagaki K , Maruyama S , Kanayama S , Wada D , Yoshihara T , et al. A case of right atrial thrombus in the Chiari network after blunt cardiac rupture. Acute Med Surg. 2024;11 :e70007. 10.1002/ams2.70007
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pmcINTRODUCTION

The Chiari network (CN) was first described by Hans Chiari in 1897 and is considered an embryologic remnant resulting from incomplete resorption of remnants of the right sinus venosus valve. The CN is recognized as floating reticular or linear structures in the right atrium that are attached to the anterior surface of the right atrium or atrial septum near the inferior vena cava. Its prevalence ranges from 1.5% to 13.6%. 1 , 2 Most patients are asymptomatic, but occasionally an association between the CN and thrombosis in the right atrium has been reported. We present a case in which the CN was considered to be involved in thrombus formation in the right atrium during the postoperative course following blunt cardiac rupture.

CASE REPORT

A previously healthy 19‐year‐old female without comorbidities was injured in a motor vehicle accident. When emergency medical service personnel arrived, they could not palpate her radial artery pulse. She complained of chest pain and was transported to our emergency center. Her vital signs on arrival were Glasgow Coma Scale, 14; pulse rate, 85/min; and respiratory rate, 30/min. Blood pressure and pulse oximetry were not measured. A focused assessment with sonography for trauma revealed the collection of pericardial fluid. Her arterial blood gas values on 21% oxygen were pH 7.36, PaO2 51 mmHg, PaCO2 36.4 mmHg, HCO3− 20.7 mEq/L, base excess −4.3 mEq, and lactate 3 mmol/L.

Although pericardiocentesis was attempted after tracheal intubation, the common carotid artery could not be palpated, so we performed left anterolateral thoracotomy and a large amount of blood gushed out after the pericardial incision. After this, her blood pressure improved, so clamshell thoracotomy was performed to evaluate her cardiac injury, which revealed a 1‐cm laceration of the superior vena cava‐right atrial junction. Bleeding was controlled with a Satinsky clamp, and closure was performed using 4‐0 polypropylene sutures. Intraoperative bleeding was 2477 mL. She was transfused with 10 units of red cell concentrate and 12 units of fresh frozen plasma. Finally, we diagnosed blunt cardiac rupture and facial contusion and calculated her severity as follows: Injury Severity Score, 26; Revised Trauma Score, 5.3522; and probability of survival calculated with the Trauma and Injury Severity Score, 0.865.

Transthoracic echocardiography (TTE) was performed on day 6 after injury, and two hyperintense linear structures floating in the right atrium were observed that were suspicious for thrombus (Figure 1). A contrast‐enhanced computed tomography scan was performed, but no pulmonary arterial embolism was detected, and no deep venous thrombosis (DVT) was found. Based on her disease course, a diagnosis of right atrial thrombosis adhering to the suture was made. Anticoagulation therapy with unfractionated heparin was initiated at 15,000–20,000 units/day to attain a target‐activated partial thromboplastin time of 50–60 s. TTE on day 10 after the start of anticoagulation therapy showed that the thrombus had tended to shrink. Anticoagulation was shifted to a direct‐acting oral anticoagulant (apixaban 10 mg/day), and the patient was discharged to home on day 27 of hospitalization without sequelae. Anticoagulation was administered in total for 8 weeks because TTE confirmed that the thrombus had disappeared, and TTE at 3 and 6 months revealed a string‐like appearance in the right atrium and a structure that appeared to be a CN (Figure 2). The anatomic location of the CN in the right atrium did not coincide with the suture site, suggesting that thrombus caused by the trauma had adhered to the originally existing CN in the right atrium (Figure 3). No screening was performed in this case for thrombophilia‐related factors such as protein C or protein S deficiency. There was no change between 3 and 6 months after injury, so the outpatient visits were terminated after 6 months and echocardiography has not been performed since then.

FIGURE 1 Transthoracic echocardiography on day 6 after injury. Parasternal right ventricular inflow view (A) and apical four‐chamber view (B). Some highly mobile structures are shown in the right atrium (red arrow).

FIGURE 2 Transthoracic echocardiography after 6 months. Parasternal right ventricular inflow view (A) and apical four‐chamber view (B). The thrombus has completely disappeared, and the Chiari network is seen in the right atrium (red arrow).

FIGURE 3 Anatomic location of thrombus in the Chiari network and suture site.

DISCUSSION

Although the CN is usually considered clinically unimportant, there have been occasional reports of thrombus adherence to the CN resulting in right atrial masses and pulmonary embolism, 3 , 4 and cases in which the network has become a reservoir for infective endocarditis, 5 suggesting its potential to cause a variety of pathological conditions. The present report is the first, to our knowledge, to describe the presence of a CN diagnosed after treatment for trauma. There were two possible reasons for thrombus adhesion to the CN: thrombus formation in the CN due to hypercoagulability after severe trauma, or trapping of deep venous thrombus by the CN acting as a filter. There have been case reports of intracardiac thrombus due to hypercoagulable states after severe trauma and traumatic intracardiac thrombus, suggesting that intracardiac thrombus is more likely to form after cardiac injury or severe trauma that requires massive blood transfusion. 6 , 7 Furthermore, there are also reports of thrombus formation in the CN due to hypercoagulability in patients with active lung cancer. 8 Thus, the thrombus in our patient may have formed in the CN because of severe trauma that required massive blood transfusion, with hypercoagulability possibly continuing after the surgery. As we did not investigate thrombophilia‐related factors such as protein C deficiency or protein S deficiency, we cannot rule out this possibility.

The role of the CN in thromboembolic events is controversial. It may act as a nidus for thrombus formation or play a protective role as an inferior vena cava filter in the case of polycythemia 9 or pulmonary embolism. 10 Although DVT was not detected in our patient during hospitalization, the possibility of a DVT migrating to and being trapped in the CN cannot be ruled out. However, we can only speculate as there is no clear evidence that cardiac rupture or massive blood transfusion is associated with thrombosis of the CN, and there are no reports of thrombus formation in the CN as a result of trauma. Long‐term clinical laboratory findings are insufficient to show how the CN was involved in thrombus formation.

Despite the lack of clear criteria regarding the indication for surgery and anticoagulant therapy in cases of thrombus formation due to a CN, there have been reports of surgical thrombectomy in patients in whom the thrombus was thought to have been involved in acute pulmonary thromboembolism. 4 Our patient showed no evidence of pulmonary embolism despite the presence of thrombus in the right atrium, and the thrombus disappeared with anticoagulation therapy, so the patient was treated conservatively. After confirming the disappearance of thrombus by periodic echocardiography, we discontinued anticoagulation therapy, and upon confirming no recurrence of the thrombus, we terminated outpatient follow‐up.

It is important to recognize the presence of the CN after cardiac injury or severe trauma requiring massive blood transfusion as the patient may be in a hypercoagulable state and prone to intracardiac thrombus formation, and the presence of the CN may contribute to the occurrence of thrombus in the right atrium.

CONCLUSION

The CN is a potential source of thrombus formation in the right atrium after cardiac trauma or trauma requiring massive blood transfusions, which can lead to fatal pulmonary embolisms. Right intra‐atrial thrombi are rare and may warrant search of the CN in conditions in which hypercoagulation is anticipated.

CONFLICT OF INTEREST STATEMENT

The authors declare no conflicts of interest. Dr. Yasuyuki Kuwagata is an Editorial Board member of the Acute Medicine & Surgery journal and a co‐author of this article. To minimize bias, this author was excluded from all editorial decision‐making related to the acceptance of this article for publication.

ETHICS STATEMENT

Approval of the research protocol: Not applicable.

Informed consent: Informed consent for publication was obtained from the patient's parents.

Registry and the registration no. of the study/trial: Not applicable.

Animal studies: Not applicable.

ACKNOWLEDGMENTS

We would like to thank Rise Japan LLC for editing the English language.

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available from the corresponding author upon reasonable request.
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