A single coronary artery with a fistula draining into the left ventricle: a pediatric case description

Introduction

The coexistence of a single coronary artery (SCA) and coronary artery fistula (CAF) is a rare congenital anomaly. This combination is exceptionally uncommon within the pediatric population, particularly when the CAF drains into the left ventricle (LV)—a distinct scenario from the more frequent right-sided drainage favored by lower pressure gradients (1). Current literature offers limited guidance on management of such complex anatomy in asymptomatic children, especially regarding the feasibility and planning of minimally invasive interventions (2). This case report describes the successful transcatheter closure of a large, tortuous LV-draining CAF in a child with underlying SCA. It highlights the pivotal role of multimodal quantitative imaging in diagnosis, anatomical risk stratification, and the formulation of a tailored interventional strategy, contributing to the management paradigm for this rare condition.

Case presentation

A 7-year-old asymptomatic girl was referred to our tertiary center for a routine postoperative echocardiogram, three years after undergoing uneventful surgical repair of atrial septal defect (ASD) at an external hospital; no regular follow-up had been conducted since the surgery. At initial presentation to our hospital, transthoracic echocardiography incidentally revealed a markedly dilated coronary system. Quantitative analysis against pediatric norms (body surface area: 0.93 m²) showed severe aneurysmal dilation of the left coronary artery (LCA, 4.7 mm, Z-score +4.1) and right coronary artery (RCA, 4.5 mm, Z-score +3.7). An abnormal conduit was identified between the RCA and the left ventricle (LV), with a fistulous orifice of approximately 2.5 mm at the posterior mitral annulus. Color Doppler revealed a high-velocity (peak 3.5 m/s) diastolic shunt from this orifice into the LV outflow tract. In keeping with this significant shunt, the LV was enlarged (end-diastolic dimension of 40 mm, Z-score +2.8), confirming volume overload. Comprehensive evaluation showed preserved LV systolic function (LVEF 65%), no regional wall motion abnormalities, no significant mitral or aortic regurgitation, and a normal estimated right ventricular systolic pressure (Figure 1A,1B).

Figure 1 Multimodal imaging and transcatheter closure of a coronary artery fistula in a pediatric patient with a single coronary artery. (A,B) Transthoracic echocardiography. A dilated coronary artery fistula (arrow) is seen terminating at the LV free wall (A). Color Doppler reveals a high-velocity diastolic jet from the fistula into the LV cavity, confirming the left-to-left shunt (B). (C-E) Coronary CTA. Multiplanar (C-E) reconstructions map the complex, tortuous course of the fistula (white double arrowheads). It originates from the left coronary system, courses anteriorly and rightward, traverses the atrioventricular groove, and finally drains into the LV near the posterior mitral leaflet (black asterisk, E). CTA precisely delineated the anatomy for procedural planning. (F,G) Diagnostic angiography. Ascending aortic (F) and selective right coronary (G) angiography demonstrate the large, tortuous fistula (white arrows) arising from the proximal left coronary bed. The absence of a right coronary ostium in its normal sinus (red arrow, G) confirms the SCA anomaly. (H-J) Procedural angiography and fistula cannulation. A coronary guidewire was advanced through the fistula termination (H). A 6F sheath was then delivered over an arterio-arterial rail, allowing for selective angiography within the fistula (I,J). This clearly defined the SCA anatomy—left anterior descending (white arrow), left circumflex (green arrow), first diagonal (D1, yellow arrow), and the anomalously originating right coronary artery (RCA, red arrow)—and precisely outlined the entire fistulous tract (white arrowheads) and its LV drainage site (white asterisk). (K) Device deployment. A 6/6-mm Amplatzer Vascular Plug II (red star) was delivered via a guiding catheter and deployed at the fistula’s drainage site into the LV. (L) Final result. Post-occlusion angiography confirms complete fistula closure with the Amplatzer Vascular Plug II in situ (red star) and no residual flow, while perfusion to all native coronary branches is preserved (white arrows). CLVF, coronary-left ventricular fistula; CTA, computed tomography angiography; LA, left atrium; LAD, left anterior descending artery; LCX, left circumflex artery; LV, left ventricle/left ventricular; LVEF, left ventricular ejection fraction; RA, right atrium; RCA, right coronary artery; RV, right ventricle; SCA, single coronary artery.

To define the complex anatomy, coronary computed tomography angiography (CTA) was performed on a 256-slice scanner with retrospective ECG-gating and bolus-tracking. Coronary CTA delineated the complex anatomy as follows: (I) origin: a single coronary ostium from the left sinus (Lipton Type L-II) (3); (II) left coronary system: the LCA gave rise to a markedly dilated left anterior descending artery (LAD, 7.0 mm, Z-score +15.4) and left circumflex artery; (III) right coronary system: the RCA arose anomalously from the proximal LAD and followed a benign anterior course anterior to the right ventricular outflow tract, with no interarterial or intramural segment; (IV) fistula: the proximal RCA gave rise to a large, tortuous fistulous tract (maximum diameter 7.0 mm) that coursed rightward, traversed the atrioventricular groove, and ultimately drained into the LV infero-posterior to the posterior mitral annulus; (V) coronary dimensions: the RCA demonstrated progressive tapering from its origin (5.5 mm, Z-score +5.9) to its mid segment (5.0 mm, Z-score +4.8) and distal segment (4.4 mm, Z-score +3.5). This anatomy, combined with the quantified diastolic shunt, confirmed a hemodynamically significant left-to-left shunt (Figure 1C-1E).

The child was asymptomatic. Cardiac auscultation revealed a diastolic murmur audible over the left 3rd and 4th intercostal spaces. No abnormality in ECG or X-ray was detected. All laboratory findings including cardiac enzymes were normal. Nevertheless, a multidisciplinary heart team finally recommended treatment rather than observation based on the following key findings. Firstly, the severity of coronary aneurysms was unequivocal, with Z-scores exceeding +5.0 in multiple segments, which were far surpassing guideline-based thresholds for pathological dilation and indicating a substantial long-term risk of thrombosis or myocardial ischemia independent of the fistula (4). Secondly, objective evidence of left ventricular volume overload was confirmed by an enlarged LV end-diastolic dimension (40 mm, Z-score +2.8), directly attributable to the diastolic shunt and representing a hemodynamic burden analogous to chronic aortic regurgitation that could progress to heart failure if uncorrected. Thirdly, the fistula itself demonstrated high-risk anatomical and physiological features, including a large caliber (7.0 mm aneurysmal segment), a high-velocity diastolic jet (peak 3.5 m/s), and drainage into the high-pressure LV cavity, all indicative of a hemodynamically significant left-to-left shunt.

Next, the rationale for percutaneous closure was refined based on specific anatomical and technical considerations. First, selective coronary angiography confirmed the absence of normal branches from the fistulous segment, ensuring safe occlusion without risk of iatrogenic ischemia. Given the fistula’s large proximal aneurysm and narrower terminal orifice draining into the LV, a distal occlusion strategy was chosen to minimize the length of excluded aneurysmal tissue and reduce thrombosis risk (Figure 1F,1G). Due to the significant diameter and tortuosity, a vascular plug was preferred over coils. Therefore, a 6 mm Amplatzer™ Vascular Plug II (AVP II; Abbott, Chicago, IL, USA) was selected for its precise, stable, and retrievable design, which is a critical safety feature for a high-pressure chamber. The device was oversized by 20–30% relative to the distal landing zone to ensure secure anchorage and complete occlusion while minimizing embolization risk.

Diagnostic catheterization prior to intervention recorded normal right heart and left ventricular end-diastolic pressures, confirming the absence of overt hemodynamic congestion. A step-up in oxygen saturation by Qp: Qs measurement was not assessed, as the left-to-left shunt physiology was already definitively established by imaging. Additionally, during the procedure, systemic anticoagulation was achieved with intravenous unfractionated heparin to maintain an activated clotting time higher than 250 seconds. To further mitigate this risk, bilateral femoral arterial access was obtained. A coronary guidewire was advanced from the right side through the fistula and into the ascending aorta, where it was snared and externalized via the left femoral sheath to create a stable “arterio-arterial” rail (Figure 1H-1J). This rail provided the essential support to advance a stable 6F long sheath deep into the tortuous fistula. The AVP II was then deployed under meticulous fluoroscopy with a snare on standby. Additionally, immediate post-deployment angiography showed preserved flow in all native coronary branches (Figure 1K,1L). Furthermore, no ST-segment changes were observed on continuous ECG monitoring during or after the procedure. Post-operative transthoracic echocardiography showed normal left ventricular wall motion, and serial cardiac enzyme levels remained within normal limits.

The patient was prescribed a 6-month course of dual antiplatelet therapy comprising clopidogrel (0.6–0.8 mg/kg/day) and aspirin (3–5 mg/kg/day), per our institutional protocol for device closure in a coronary artery with pre-existing aneurysmal dilation. She was discharged on postoperative day 7. A structured follow-up plan was instituted, including clinical review and echocardiography at 1, 6, and 12 months to assess symptoms, fistula closure, coronary dimensions and LV function. Surveillance coronary CTA will be considered at 1 year. The patient remained well at her 3-month visit, with echocardiography confirming persistent closure and stable coronary dimensions. Serial assessment demonstrated no new symptoms, no residual shunt, and no progression of coronary dilation.

Ethical considerations

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient’s legal guardians for publication of this article and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Discussion

The reported case of successful transcatheter closure of an LV-draining CAF in a pediatric patient with an underlying SCA highlighted a novel application of catheter-based techniques in complex anatomy.

Although most patients with CAFs are asymptomatic initially, elderly individuals may develop symptoms such as exertional chest pain, fatigue, palpitations, arrhythmias, congestive heart failure, or even sudden death (5). The two primary mechanisms underlying CAF pathophysiology are coronary steal and cardiac chamber volume overload. During diastole, the decreased pressure within the LV creates a gradient that diverts blood flow from a major coronary artery directly into the LV. This aberrant shunt can ultimately lead to chronic LV volume overload, paralleling the hemodynamic effects seen in aortic regurgitation (6). Therefore, even in asymptomatic patients, early diagnosis and definitive treatment of CAF are now strongly recommended due to potential long-term complications (7). Although the most common treatment for CAF is surgical ligation, coil embolization, and catheter-mediated stent occlusion are increasingly being performed (8,9). When performed on carefully selected patients, percutaneous closure can achieve favorable outcomes in appropriately selected patients and offers the potential advantage of avoiding the risks associated with thoracotomy (10). Nevertheless, when vessels are extremely tortuous or unable to deliver a catheter far enough through the coronary trunk, surgical treatment should be recommended as the first-line approach (11). For this case, decision-making was first guided by a critical safety assessment: coronary CT angiography confirmed that the anomalous RCA coursed anterior to the right ventricular outflow tract, thereby ruling out a high-risk “malignant” anatomic pattern. This allowed the treatment focus to remain squarely on the hemodynamic impact of the fistula itself.

This case presented a technical challenge due to the fistula’s tortuosity, large caliber, and drainage into a high-pressure chamber. The successful strategy employed a distal occlusion approach using a retrievable vascular plug, delivered over a stable “arterio-arterial” rail created via bilateral femoral access. This technique was essential for navigating the complex anatomy and mitigating the risk of device embolization into the LV. While transcatheter closure was successfully performed in this case, the choice between surgical and percutaneous approaches should be individualized based on anatomical factors, patient characteristics, and local expertise. This single case does not establish superiority of one modality over another, but rather demonstrates that percutaneous closure is a feasible option in selected patients with complex anatomy.

Despite the benefits and non-invasive nature of catheter intervention, several postoperative complications such as coronary thrombosis, myocardial infarction, coronary perforation or dissection and risk of device embolization to the LV should be carefully monitored. Therefore, oral anticoagulation or extended dual antiplatelet therapy should be considered. Nevertheless, there are not enough data in the current literature about how to plan anticoagulation treatment for these children (12). Shah et al. described a 20-year experience with percutaneous closure of CAF in adult patients and found that 3 patients developed thrombotic occlusion of a proximal coronary artery, of whom two had only oral anticoagulation treatment (13). In this case, dual antiplatelet therapy was chosen over oral anticoagulation based on a balanced risk assessment. Firstly, the successful elimination of the high-flow shunt and the absence of a large residual stagnant aneurysm sac lowered the perceived thrombotic burden. Secondly, dual antiplatelet therapy effectively targets acute, platelet-rich thrombus on the device and diseased endothelium, and it offers a more manageable safety profile regarding bleeding risk in a young, active child compared to warfarin. Thirdly, angiography confirmed no residual flow into the fistula and no stagnant contrast within the excluded aneurysmal segment, reducing the risk of in-situ thrombosis. However, given the pre-existing severe coronary aneurysms which themselves confer an independent thrombotic risk, extended antiplatelet coverage was deemed necessary. Nevertheless, we explicitly acknowledge that the optimal duration and regimen in pediatric cases are not standardized and require further study. Additionally, we acknowledge that the follow-up period in this case is relatively short. Given the known risks of late thrombosis, recanalization, and coronary remodeling following CAF closure, longer-term surveillance is essential. Our findings should therefore be interpreted as demonstrating short-term procedural success and safety, while the durability of closure, evolution of the aneurysmal coronary segments, and optimal long-term management remain to be established through extended follow-up.

Conclusions

This case demonstrates the short-term feasibility and safety of percutaneous closure for this rare anomaly. However, long-term outcomes require further investigation with extended follow-up to assess late complications and coronary remodeling.

Acknowledgments

None.

Footnote

Funding: This work was supported by the Natural Science Foundation of Sichuan Province (Nos. 2026NSFSC1715, 2025ZNSFSC0705); the Key Research and Development Project of Chengdu Science and Technology Bureau (Nos. 2024-YF05-00237-SN, 2024-YF05-00300-SN); National Natural Science Foundation of China (No. 82370236); and the National Key Research and Development Program of China (No. 2022YFC2703902).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-2025-1-2511/coif). H.D. reports the funding from the Natural Science Foundation of Sichuan Province (No. 2025ZNSFSC0705) and the Key Research and Development Project of Chengdu Science and Technology Bureau (No. 2024-YF05-00300-SN). S.S. reports the funding from the Key Research and Development Project of Chengdu Science and Technology Bureau (No. 2024-YF05-00237-SN). K.Z. reports the funding from the National Natural Science Foundation of China (No. 82370236) and the National Key Research and Development Program of China (No. 2022YFC2703902). The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient’s legal guardians for publication of this article and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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