INTRODUCTION:

Coronary artery fistulas (CAFs) are abnormal communications between a coronary artery and a cardiac chamber or great vessel ¹, with an estimated prevalence of approximately 0.002% in the general population and 0.1–0.8% among adults undergoing catheterization². Hemodynamically significant fistulas generate turbulent flow and endothelial injury that may predispose to infective endocarditis (IE) ^3,4. Although rare, IE in the context of CAF can lead to devastating complications including embolic stroke in young patients ^5–7.

Case Presentation:

A 25-year-old woman presented with history of headache and malaise. There was no remarkable history of intermittent fever or joint pain. Brain imaging showed a late-acute thrombotic infarction in the right parietal cortical–subcortical region. On examination, a diastolic murmur was audible at the aortic area.

Transthoracic echocardiography (TTE) demonstrated mobile vegetations on the right coronary cusp (RCC) (13×5 mm) and non-coronary cusp (NCC) (11×6 mm) of the aortic valve (Fig1). Blood cultures grew Gemella morbillorum; targeted therapy with ampicillin plus gentamicin was initiated for 21 days.

Figure 1. TTE showed multiple oscillating mass on RCC sized (13 mm x 5 mm) and NCC (11 mm x 6 mm)

During surgery for aortic valve replacement with a bioprosthetic valve, intraoperative transesophageal echocardiography (TEE) identified a 7-mm fistula originating from the right coronary artery and draining into the right atrium (Fig 2). The fistulous tract was surgically closed during the same session.

Figure 2. Incidental finding: Fistula from Right Coronary Artery to Right Atrium sized 7 mm

Post-operative recovery was uneventful, with hemodynamic stability and gradual improvement in functional status on follow-up.

This case is significant as it highlights a rare presentation of infective endocarditis associated with a coronary artery fistula, which complicates the typical presentation and management. The discovery of the fistula was incidental, suggesting that such anatomical abnormalities can be easily overlooked in non-general anesthesia settings, emphasizing the importance of thorough evaluation in similar contexts. This provides valuable insights into the challenges and complexities of diagnosing and managing infective endocarditis with underlying rare cardiac anomalies.

DISCUSSION:

Epidemiology and anatomy: CAFs most commonly originate from the right coronary artery or the left anterior descending artery ^8,9 and typically drain into right-sided chambers—most frequently the right ventricle or right atrium ^10,11. The anatomical configuration in this patient—right coronary artery to right atrium—is consistent with commonly reported drainage sites. ^12,13

Pathophysiology: CAFs create continuous or diastolic shunting with high-velocity turbulent jets that injure endothelium and may produce a nidus for bacterial adhesion ^14,15. Small fistulas are usually asymptomatic ¹⁶. Larger fistulas can also cause coronary steal, reducing perfusion distal to the communication and predisposing to ischemia ^16–18. In this patient, the combination of aortic valve vegetations and a concealed RCA-to-RA fistula provides a plausible pathway for bacteremia with G. morbillorum to seed damaged endocardium and generate embolic phenomena.

Microbiology: The most common bacteria involved in IE are Staphylococcus aureus and Streptococci ^19,20. G. morbillorum is a rare cause of native-valve IE^19,21,22linked to oropharyngeal or gastrointestinal sources²². Despite its low virulence, bacteremia in the presence of endothelial injury or prosthetic material may allow colonization and vegetation formation. ^22,23

Diagnostics: TTE remains first-line to detect vegetations and assess valve dysfunction ²⁴, whereas TEE improves sensitivity for periannular complications and can delineate fistulous origins and terminations ²⁵. Coronary computed tomographic angiography (CTA) or invasive angiography offers precise anatomical mapping, particularly when percutaneous closure is contemplated ^26,27.

Management: Indications for fistula closure include symptoms, significant shunt, and complications such as IE, ischemia, or aneurysmal change.^17,28 When valve surgery is indicated, concomitant surgical closure of the fistula, as performed here, is reasonable to achieve definitive management in a single session.

Practice implications: In young IE patients with embolic events and without typical risk factors, clinicians should consider occult structural lesions such as CAFs and adopt a low threshold for advanced imaging (TEE and/or CTA). ^29–31

CONCLUSION:

Hidden coronary artery fistulas may underlie IE and embolic events in young patients. A high index of suspicion and routine use of TEE (and/or CTA) can reveal surgically correctable lesions, enabling definitive management in a single session. The successful resolution of this case through surgical intervention underscores the importance of multidisciplinary management and vigilance in cases of infective endocarditis, especially in atypical presentations. This report adds valuable knowledge to the limited literature on the association between coronary artery fistulas and infective endocarditis, suggesting the need for careful evaluation of potential anatomical contributors in young patients with IE.

STATEMENT OF ETHICS:

Institutional requirements for case reports were reviewed; formal ethics board approval was not required for a single-patient case report in our jurisdiction.

PATIENT CONSENT:

Written informed consent for publication of this case and accompanying images was obtained from the patient. Identifying details have been removed to ensure anonymity.

CONFLICT OF INTEREST:

The authors have no conflicts of interest to declare.

ACKNOWLEDGEMENTS:

The authors thank the cardiothoracic surgical and anesthesia teams for their assistance in the perioperative management of this patient.

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Received on 07.12.2024 Revised on 21.03.2025

Accepted on 28.05.2025 Published on 01.12.2025

Available online from December 06, 2025

Research J. Pharmacy and Technology. 2025;18(12):5839-5842.

DOI: 10.52711/0974-360X.2025.00842

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