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\begin{document}

\title{A giant right atrial appendage aneurysm in an infant: a case report}



\author[1]{Jianming Yue}%
\author[1]{Qi Wang}%
\author[1]{Bin Liu}%
\author[1]{Leng Zhou}%
\affil[1]{Sichuan University West China Hospital}%


\vspace{-1em}



  
  \date{June 02, 2024}


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\selectlanguage{english}
\begin{abstract}
Right atrial appendage aneurysms (RAAAs) are extremely rare in cardiac
anomaly. According to the literature, no more than 25 cases have been
reported so far, among which only 3 cases were children. Here, we
reported an infant with a giant RAAA and severe symptoms. The RAAA was
diagnosed by echocardiography and surgically resected under
cardiopulmonary bypass. The role of transesophageal echocardiography was
very important during the aneurysm resection surgery, which helped
surgeons to plan surgical procedures during the surgery and evaluate the
surgical effect postoperatively.%
\end{abstract}%



\sloppy


\textbf{Title page}

\textbf{Title}

A giant right atrial appendage aneurysm in an infant: a case report

\textbf{Running title}

Right atrial appendage aneurysm

\textbf{Author}

Jianming Yue MD\textsuperscript{1,2} \textbar{} Qi Wang
MD\textsuperscript{1,2} \textbar{} Bin Liu
MD\textsuperscript{1,2} \textbar{} Leng Zhou PhD\textsuperscript{1,2}

Department of Anesthesiology, West China Hospital, Sichuan university

The Research Units of West China(2018RU012)-Chinese Academy of Medical
Sciences, West China Hospital,Sichuan University\textbf{Corresponding
author}Leng Zhou, No. 37 Guoxue Lane, Chengdu 610041, Sichuan Province,
China, \emph{zhoulenghx@foxmail.com,} +86
18980601585\textbf{Acknowledgement}We thank the patient's guardian for
allowing us to publish the case report and to use the images taken.

\textbf{Supported by none.}

\textbf{Abstract}

Right atrial appendage aneurysms (RAAAs) are extremely rare in cardiac
anomaly. According to the literature, no more than 25 cases have been
reported so far, among which only 3 cases were children. Here, we
reported an infant with a giant RAAA and severe symptoms. The RAAA was
diagnosed by echocardiography and surgically resected under
cardiopulmonary bypass. The role of transesophageal echocardiography was
very important during the aneurysm resection surgery, which helped
surgeons to plan surgical procedures during the surgery and evaluate the
surgical effect postoperatively.

\textbf{KEYWORDS}

right atrial appendage aneurysms, infant, echocardiography, giant

\textbf{1 \textbar{} INTRODUCTION}

Atrial aneurysm is rare in cardiac anomaly, most of which are left
atrial aneurysms in adults. Right atrial appendage aneurysms (RAAAs) are
extremely rare compared to other cardiac aneurysms, especially for
infants and pediatric population. According to the literature, no more
than 25 cases have been reported so far, among which only 3 cases are
infants or neonates.\textsuperscript{1,2} A systematic review published
in 2014 found that the highest morbidity of RAAAs was in the third
decade of life, with cases noted from the perinatal period to 72~years
of age.\textsuperscript{3} RAAAs usually involve free walls and atrial
appendages, most have congenital origins and develop in the course of
pregnancy.\textsuperscript{2,4} Generally, patients with RAAA are
usually asymptomatic and are diagnosed incidentally or until they
present some clinical symptoms like arrhythmia or
dyspnea.\textsuperscript{5} Pulmonary thromboembolism is a common
complication due to blood stasis in the
aneurysm.\textsuperscript{6}However, there is no guideline for the
treatment of this condition, and surgical resection is safe and can be
performed through sternotomy with or without cardiopulmonary bypass for
symptomatic patients.\textsuperscript{2,5} Here, we reported an infant
with a giant RAAA and severe symptoms who underwent surgical resection
of the aneurysm.

\textbf{2 \textbar{} CASE REPORT}

A 1-year-old infant was first disclosed right atrial enlargement at the
26 weeks of gestation, but the parents were unable to provide detailed
prenatal examination data. The infant had been asymptomatic and had not
received any echocardiography until he got a prolonged unhealed cold and
eventually developed pneumonia accompanying with
supraventricular~tachycardia and dyspnea at the local hospital. After
the infection and arrhythmia were controlled by antibiotics and digoxin,
he was transferred to our hospital.

Preoperative chest X-ray showed an enlarged cardiac shadow with a
prominent right atrial contour (Figure 1A). Transthoracic
echocardiography (TTE) disclosed a giant right atrial aneurysmal
structure measured 7.8 \selectlanguage{ngerman}× 7.5 cm and a large patent foramen ovale (PFO)
(Figure 1B). The anatomical position and structure of the tricuspid
valve (TV) were normal. The right ventricle (RV) and left atrium (LA)
were compressed by the abnormal cavity, whereas tricuspid regurgitation
was minimal. The other valves and left ventricle were normal with good
systolic function. An enhanced cardiac computed tomography scan was
requested and showed a large aneurysmal dilatation of the right atrial
appendage with no internal thrombi (Figure 2). Thus, the infant was
diagnosed with a giant right atrial appendage aneurysm complicated with
a PFO and was indicated to surgery considering the large size of RAAA,
the PFO and the previous episodes of supraventricular tachycardia and
dyspnea. After induction of anesthesia, transesophageal echocardiography
(TEE) was performed to evaluate the RAAA (Figure 3A) and cardiac
structure. It revealed that the free wall of the right ventricle (RV)
was compressed by the large aneurysm (Figure 3B). Although blood flow in
the right atrium and RAAA was slow, no thrombus was found. Both
ventricles and left atrium were of normal size and function (Figure 3B).
TEE also revealed a large PFO and mild tricuspid regurgitation with
normal RV systolic pressure. Considering the large aneurysm might have
higher risks of bleeding and arrhythmia, the surgeons performed the
aneurysm resection under cardiopulmonary bypass (CPB). The giant RAAA
occupied almost all pericardial space (Figure 4A). The aneurysm sac was
opened, an extremely thin atrial wall was observed, no thrombus was
found and there were many tube-like structures distributed on the inner
wall during surgery (Figure 4B). The aneurysm was resected and the PFO
was closed. After weaning of CPB, postoperative TEE showed that the
cardiac structure was normal and the tricuspid valve functioned normally
without regurgitation or insufficiency (Figure 5A). And the
postoperative TTE dimension of the right atrial appendage showed a
decrease in right atrial size to 2.0 cm × 2.35 cm (Figure 5B). Later
pathological examination confirmed the diagnosis of RAAA (Figure 5C).

The postoperative course was uneventful and the infant was discharged on
the 5th day after the surgery. He had a full recovery without any
complications at the three-month follow-up.

\selectlanguage{english}\textbf{3 \textbar{} DISCUSSION}

Compared with left atrial appendage aneurysm, RAAA is a rare cardiac
anomaly that was first reported in 2001 which thought to be caused by
dysplasia of the muscular wall of the right atrium (RA) and right atrial
appendage.\textsuperscript{7,8} Most of these aneurysms affect adults in
their third decade of life but they can also occur in children and
neonates and can also be detected prenatally.\textsuperscript{2,3}

The diagnosis can be confirmed by imaging modalities, especially initial
echocardiography and chest X-ray.\textsuperscript{9} Both TTE and TEE
are very effective in diagnosis and distinguish of the aneurysm, such as
pericardial cysts, Ebstein's anomaly, cortriatriatum and
thrombosis.\textsuperscript{10}Agitated saline study with
echocardiography can be performed to confirm the diagnosis and to
distinguish from pericardial effusion or cysts, demonstrating
opacification of the RAAA and RV.\textsuperscript{2} TEE plays an
important role in further preoperative evaluation and planning surgical
procedures during resection of RAAA. In this case, before the aneurysm
resection TEE presented the giant RAAA, PFO and RV compression. During
the surgery, surgeons concerned the resection of the aneurysm might
change the entire anatomical structure, leading to tricuspid valve
dysfunction. Additionally TEE played a key role in confirming valve
competency during the surgery. In this case, the postoperative TEE
confirmed that the tricuspid valve still functioned normally without
regurgitation or insufficiency. Therefore, the patient was not indicated
to tricuspid valvuloplasty. Taken together, TEE is very helpful for
surgeons to formulate detailed surgical plan and evaluate the effect of
surgical correction during cardiac surgery. Finally, TTE is useful for
long-term follow-up on this case since there is no report regarding
postoperative recurrence or death after RAAA resection.

Although RAAA is a very rare anomaly in pediatric patients, prenatal
diagnosis via fetal echocardiography is possible. Clinical experience of
treatment for RAAA is limited and the natural history and optimal
management strategy are still unclear. Therefore, the therapeutic
strategies of RAAA remain controversial and aneurysm resection and
anticoagulation therapy are not recommended in all
cases.\textsuperscript{3} Surgical resection is preferred for patients
with symptoms or progressive enlargement in preventing thromboembolisms
and lowering the risk of atrial arrhythmia and heart failure, which are
the most common complications of these
aneurysms.\textsuperscript{2,3}Oral anticoagulants is recommended to
reduce the risk of thromboembolic events in patients with
contraindications to surgery.\textsuperscript{4}

In conclusion, echocardiography plays an important role in the diagnosis
and surgical resection of RAAA as well as postoperative evaluation of
surgical effect. Treatment should be modified according to the age,
presentation, imaging findings and the follow-up results.

\textbf{CONFLICTS OF INTEREST}

The authors have no conflicts of interest to disclose.

\textbf{INFORMED CONSENT}

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

\textbf{DATA AVAILABILITY STATEMENT}

No additional data.

\textbf{ORCID}

Jian-Ming Yue: 0000-0002-1826-4931

Qi Wang: 0000-0003-0509-3851

Biu Liu: 0000-0001-5503-0053

Leng Zhou: 0000-0003-3374-7007

\textbf{Author contributions:}

All the authors participated in the management of this patient and
provided suggestion for the manuscript. Jian-Ming Yue followed up the
patient closely, collected the data and written the manuscript. Qi Wang
and Bin Liu provided some suggestions about the manuscript and
management of this patient. Leng zhou reviewed the manuscript and was
the corresponding author.

\textbf{References}

1. Bachani N, Jadwani J, Joshi S, et al. Right atrial appendage aneurysm
with intractable atrial tachycardia. IHJ Cardiovascular Case Reports
(CVCR). 2019;3(3):108-111.

2. Tunks RD, Malysz J, Clark JB. Neonatal Management of a Giant Right
Atrial Appendage Aneurysm. Circulation. 2015;132:e226-228.

3. Aryal MR, Hakim FA, Giri S, et al. Right atrial appendage aneurysm: a
systematic review. Echocardiography. 2014;31:534-539.

4. Barberato SH, Barberato MF, Avila BM, et al. Aneurysm of the right
atrial appendage. Arq Bras Cardiol. 2002;78:236-241.

5. Sivakumaran L, Sayegh K, Mehanna E, et al. Use of cardiovascular
magnetic resonance in the evaluation of a giant right atrial appendage
aneurysm: a case report and review of the literature. BMC Res Notes.
2017;10:681.

6. Toufan M, Pourafkari L, Akbarzadeh F, et al. A case of right atrial
appendage aneurysm mimicking a pericardial cyst on echocardiogram. Echo
Res Pract. 2014;1:K5-8.

7. Ishii Y, Inamura N, Kayatani F. Congenital aneurysm of the right
atrial appendage in a fetus. Pediatr Cardiol. 2012;33:1227-1229.

8. Mizui S, Mori K, Kuroda Y. Ectopic atrial tachycardia due to aneurysm
of the right atrial appendage. Cardiol Young. 2001;11:229-232.

9. Moraes F, Santos CL, Lira V, et al. Congenital aneurysm of the right
atrium. Eur J Cardiothorac Surg. 2001;19:943-944.

10. Pontecorboli G, Figueras I Ventura RM, Carlosena A, et al. Use of
delayed-enhancement magnetic resonance imaging for fibrosis detection in
the atria: a review. Europace. 2017;19:180-189.

\textbf{Figure legends}

FIGURE 1 Chest X-ray showed cardiomegaly with enlarged right atrial
contour (A); The subxiphoid view of TTE showed the giant RAAA and the
PFO (B); The apical four-chamber view showed large aneurysm, measuring
7.8 x 7.5 cm (C). a = aneurysm; LA: left atrium; LV: left ventricle; MV:
mitral valve; PFO = patent foramen ovale; RA: right atrium; RAAA = right
atrial appendage aneurysm; RV: right ventricle; TTE = transthoracic
echocardiography; TV: tricuspid valve.

FIGURE 2 Enhanced cardiac computed tomography showed a large dilatation
of the right atrium and atrial appendage. LA: left atrium; LV: left
ventricle; RA: right atrium; RAAA = right atrial appendage aneurysm; RV:
right ventricle.

FIGURE 3 The intraoperative TEE showed the thin wall of right atrial
appendage aneurysm with a size of 6.1 x 7.9 cm (A); The 4-chamber view
showed the right ventricle was compressed by the atrial appendage
aneurysm (B). LA = left atrium; LV = left ventricle; MV = mitral valve;
RA = right atrium; RAAA = right atrial appendage aneurysm; RV = right
ventricle; TV = tricuspid valve.

FIGURE 4 The giant RAAA was found upon opening the pericardium (A); The
resected sac of right atrial appendage aneurysm (B). RAAA = right atrial
appendage aneurysm.

FIGURE 5 The postoperative TEE showed a normal cardiac structure and
valve function (A); The postoperative TTE showed a decreased size of
right atrium (B); Histopathological sections of the aneurysm showed
thinned myocardium and proliferated blood vessels. (x100) (C). LA = left
atrium; LV = left ventricle; MV = mitral valve; RA = right atrium; RV =
right ventricle; TV = tricuspid valve.\selectlanguage{english}
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