Introduction

Coronary cameral fistula (CCF) is a rare congenital anomaly where a coronary artery connects abnormally to a cardiac chamber. Typically arising from embryological abnormalities, CCFs can also result from traumas or surgeries. Congenital coronary anomalies occur in about 1% of the population, with CCFs making up 0.2–0.4% of these cases and appearing in 0.1–0.2% of coronary angiograms [1, 2]. The majority of cases are congenital and solitary, accounting for 0.2–0.4% of all congenital cardiac malformations [3]. These fistulas are often asymptomatic for many years and are frequently diagnosed incidentally during imaging studies [4]. In childhood, asymptomatic cases of CCF are often identified by a continuous heart murmur detected during auscultation. For children older than 3–5 years, elective closure of the fistula is recommended due to the increased risk of complications associated with the condition [5]. In symptomatic cases of CCF, patients may experience manifestations such as angina, exertional dyspnea, syncope, and palpitations. These symptoms arise due to the abnormal blood flow and increased demand on the heart caused by the fistula, which can lead to complications if left untreated [6]. Therapeutic intervention with surgical ligation or transcatheter closure (TCC) is typically performed in patients with symptomatic fistulas or in cases of complications. Percutaneous TCC is preferred because it is less invasive and avoids potential surgical complications. However, surgical closure may be necessary if the vessel is tortuous or if the fistula is large and unsuitable for TCC [7]. TCC of CCF has been advocated as a minimally invasive alternative to surgery [7]. In this study, we report the history of a 5-year-old boy with the diagnosis of coronary cameral fistula, which was treated by an Amplatzer™ duct occluder (ADO).

Case presentation

A 5-year-old Iranian boy presented to the emergency room (ER) with complaints of chest pain and dyspnea on exertion. His medical history revealed multiple similar episodes over the previous 4 months, which had not been evaluated. There was no significant family history of cardiac disease, and his drug history was unremarkable. The patient’s social history did not reveal any notable factors contributing to his condition.

On physical examination, his vital signs were stable and within normal ranges. Heart rate was 90 beats per minute, respiratory rate was 20 breaths per minute, blood pressure was 110/70 mmHg, and oxygen saturation was 98% on room air. No murmurs or abnormal heart sounds were detected during auscultation. His cardiopulmonary examination was normal, with clear lung fields and no signs of respiratory distress. Abdominal examination showed no hepatosplenomegaly, and there were no neurological deficits observed.

Methods

The patient was admitted to the pediatric cardiology ward for further evaluation and monitoring. Initial investigations included serial measurements of troponin levels and other relevant blood tests, which are detailed in Table 1. Notably, the lab results revealed mild anemia with a hemoglobin level of 11 g/dL. All other lab results were within normal reference ranges and did not show any remarkable abnormalities. An electrocardiogram (ECG) was performed, revealing normal sinus rhythm with no ST/T wave changes.

Table 1 Laboratory findings of the patient
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Transthoracic echocardiography (TTE) was then conducted, demonstrating a dilated left coronary artery (LCA) with a large aneurysm and a small orifice to the right ventricular (RV) body. The RV size and function were normal, and the left ventricular ejection fraction (LVEF) was measured at 55%. To further delineate the anatomy and confirm the diagnosis, cardiac computed tomography angiography (CTA) was performed, which substantiated the findings of a dilated LCA and coronary cameral fistula to the RV (Figs. 1, 2).

Fig. 1
figure 1

(A) and (B) Three-dimensional cardiac computed tomography angiography (CTA) images showing a coronary cameral fistula with a dilated left coronary artery (LCA) and a large aneurysm. Both views (A and B) illustrate the aneurysmal dilation of the LCA, with the arrows indicating the location of the fistula and aneurysm

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Fig. 2
figure 2

Cardiac computed tomography angiography (CTA) image showing a coronary cameral fistula (indicated by the arrow). The CTA highlights the connection between the coronary artery and a cardiac chamber, providing a clear view of the anatomical anomaly

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Subsequently, cardiac angiography was conducted, confirming the presence of a dilated LCA and a coronary cameral fistula to the right ventricle. During the procedure, the aneurysm was successfully occluded using two Amplatzer™devices (Fig. 3). Post-procedure angiography of the LCA in the right anterior oblique (RAO) view showed no aneurysmal filling, indicating a successful intervention.

Fig. 3
figure 3

Cardiac angiography:A shows the coronary cameral fistula (indicated by the arrow). B illustrates two coronary cameral fistula orifices to the right ventricular (RV) cavity (indicated by the arrow). C shows the coronary cameral fistula immediately after the use of the Amplatzer™ device (indicated by the arrow). D shows the coronary cameral fistula 2 minutes after using the Amplatzer™ device, with successful occlusion (indicated by the arrow)

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Results and follow-up

The day after the angiography, the patient’s symptoms were completely resolved. Physical examination revealed normal heart, respiratory system, and neurological function. A chest x-ray was performed, which was normal (Fig. 4). After 48 hours, the patient was discharged without any complications. Follow-up appointments were scheduled at 1, 3, and 6 months after the procedure, during which time the patient reported no abnormal symptoms or recurrences of chest pain or dyspnea.

Fig. 4
figure 4

Chest x-ray taken 1 day after the procedure, showing no signs of complications. The heart and lungs appear normal, and the Amplatzer™ devices are in place and visible (yellow arrow)

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Discussion

CCFs are rare coronary anomalies characterized by abnormal connections between a coronary artery and one of the cardiac chambers. These and abnormal connections, though uncommon, can have significant clinical implications, including the development of heart failure and non-ischaemic ischemic cardiomyopathy, as evidenced by the patient in this report [1]. In the reported case of a 5-year-old boy, the CCF presented with significant hemodynamic consequences, manifesting as chest pain and dyspnea on exertion, which necessitated prompt intervention with transcatheter closure using Amplatzer™ duct occluders.

Previous studies have shown that the majority of CCF cases are asymptomatic and often discovered incidentally during imaging studies conducted for other reasons. However, symptomatic cases, particularly those with hemodynamically significant shunts, may require intervention to prevent complications such as heart failure and ischemic damage [9] Pathophysiologically, coronary artery fistulas, including CCFs, arise from a failure of the normal development of the coronary vasculature, resulting in a direct connection between a branch of a coronary artery and a cardiac chamber, which can lead to various clinical presentations depending on the severity of the left-to-right shunt [10] These fistulae often lead to a “coronary steal phenomenon,” where blood is shunted away from the myocardium, potentially causing myocardial ischemia, particularly during increased myocardial oxygen demand, such as exercise [11].

Diagnostic methods for coronary artery fistulas often begin with noninvasive imaging techniques. TTE is useful for visualizing hemodynamically significant fistulas, while transesophageal echocardiography (TEE) provides detailed information about the origin and insertion point area in adults. Cardiac computed tomography (CT) and magnetic resonance imaging (MRI) offer excellent anatomical delineation, particularly useful for surgical planning [12, 13]. However, coronary angiography remains the gold standard for definitive diagnosis and detailed anatomical assessment of coronary artery fistulas, providing precise information on the size, course, and drainage site of the fistula [12, 14].

The use of three-dimensional echocardiography has improved the accuracy of anatomical characterization, enhancing the pre-procedural assessment and planning for interventional procedures [15].

Treatment options for CCFs vary on the basis of the clinical significance of the condition and patient comorbidities. According to the updated 2023 American Heart Association (AHA)/American college of cardiology (ACC) guidelines, the management of coronary artery fistulas has evolved to incorporate the latest evidence and a more patient-centered approach. For large fistulas, closure, using either transcatheter embolization or surgical closure, is recommended regardless of symptoms. Smaller fistulas should also be managed with these methods if complications such as ventricular dysfunction, angina, or arrhythmias are present. This approach aims to prevent severe complications and improve patient outcomes by ensuring timely and appropriate intervention [16]. The literature further indicates that transcatheter closure (TCC) is often preferred due to its minimally invasive nature. It avoids complications related to surgical interventions, such as surgical stress, bleeding, infections, and inflammatory responses from cardiopulmonary bypass. In cases where TCC is not feasible due to anatomical challenges, surgical repair remains the most effective treatment. This involves the obliteration of the fistula through epicardial and endocardial ligations. The choice of therapy is influenced by the size, location, and complexity of the fistula, as well as the patient’s overall health condition and the presence of comorbid conditions [12, 17]. An innovative stent-assisted coil occlusion technique has also been successfully utilized, providing a promising option for complex cases where traditional methods are not suitable [17].

Complications of untreated CCFs include heart failure, myocardial ischemia, arrhythmias, and endocarditis [11, 18]. The prognosis after treatment is generally favorable, especially with timely intervention. Regular follow-up is essential to monitor for potential recurrence of the fistula or the development of related complications [11]. Continuous follow-up is crucial to monitor for any potential recurrence of the fistula or the emergence of related complications. Moreover, CCFs can lead to increased left ventricular end-diastolic pressure, left ventricular hypertrophy (LVH), congestive heart failure (CHF), atrial fibrillation (AF), ventricular tachyarrhythmias (VT), chronic myocardial ischemia, and myocardial infarction (MI). Hemopericardium can result from the rupture of an associated aneurysm, which is a life-threatening complication [19]. Effective occlusion of CCF can be obtained in more than 90% of cases with the appropriate use of occluder devices, highlighting the importance of careful pre-procedural planning and device selection to minimize the risk of complications [15].

Zenooz et al. [4] emphasize the importance of early diagnosis and intervention for CCFs due to the high prevalence of late symptoms and complications, highlighting the role of CT angiography and conventional angiography in the precise delineation of coronary anomalies [10]. Boyle et al. [9] also support the use of multimodality imaging for the diagnosis of CCFs, noting that advances in noninvasive imaging have improved the detection and management of these anomalies [9]. Furthermore, Wolking et al. [20] highlight the potential for mural thrombosis, rupture, aneurysm formation, and intimal rupture as complications of coronary cameral fistulae, highlighting the importance of careful monitoring and timely intervention [20] Minhas et al. [21] also reported that larger fistulas could cause coronary artery steal, resulting in ischemia of the myocardium perfused by the coronary artery distal to the fistula, and other complications such as cardiac failure, atrial fibrillation, bacterial endocarditis, thrombosis, and embolism [21].

CCFs, though rare, are significant anomalies that can lead to severe cardiovascular issues if not treated properly. This case of a 5-year-old boy underscores the importance of prompt diagnosis and intervention. With advancements in imaging technologies such as three-dimensional echocardiography and CT angiography, the accuracy of diagnosing these anomalies and planning for procedures has greatly improved. Transcatheter closure is now the preferred treatment method due to its less invasive nature and high success rate. Continuous follow-up and diligent monitoring are crucial to prevent and address potential complications such as heart failure, myocardial ischemia, and endocarditis. Effective management of CCFs demands a collaborative approach involving cardiologists, radiologists, and interventional specialists to achieve the best patient outcomes. Similar cases reported in previous literature have been summarized and mentioned in Table 2.

Table 2 Literature review of case reports on coronary cameral fistula (CCF)
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Conclusions

Timely identification of CCFs is essential to prevent severe cardiovascular complications, including heart failure and myocardial ischemia. Advances in imaging techniques, such as three-dimensional echocardiography and CT angiography, have significantly improved diagnostic accuracy and treatment planning. Transcatheter closure has emerged as the preferred treatment modality due to its minimally invasive nature and high success rate, while surgical intervention is reserved for cases where transcatheter closure is not feasible. Regular follow-up and monitoring are crucial to detect and manage potential complications early, such as arrhythmias, myocardial infarction, and endocarditis. A multidisciplinary approach involving cardiologists, radiologists, and interventional specialists is necessary to provide comprehensive care and ensure optimal patient outcomes. Additionally, the use of innovative techniques and devices, such as stent-assisted coil occlusion, offers promising results in treating complex CCF cases where traditional methods pose challenges.