Giant Right Coronary Artery Aneurysm With Left Ventricular Fistula

Abstract

Background

Giant coronary artery aneurysms are rare vascular anomalies (<0.02% prevalence). Fistulous drainage into the left ventricle (LV) is exceptionally uncommon and may present with malignant arrhythmias or sudden cardiac arrest.

Case Summary

A 65-year-old man with hypertension and presumed cardiomyopathy experienced an out-of-hospital ventricular tachycardia arrest while on pilgrimage. Multimodality imaging revealed a 42-mm right coronary artery aneurysm with a fistulous connection to the LV, a true inferobasal LV aneurysm, and ascending aortic dilation. A multidisciplinary team recommended surgical repair and implantable cardioverter-defibrillator for secondary prevention, but the patient declined all invasive interventions after thorough counseling. He was managed medically and discharged in stable condition with a structured surveillance plan.

Discussion

This case highlights a rare triad of right coronary artery aneurysm, LV fistula, and true LV aneurysm, presenting as cardiac arrest. It underscores the importance of imaging, patient-centered decision-making, and follow-up in managing rare coronary anomalies.

Take-Home Messages

Multimodality imaging is essential for diagnosing rare coronary anomalies. Patient autonomy can override guideline-driven recommendations.

Visual Summary

Visual Summary.

3-Dimensional Reconstruction of Computed Tomography Angiography

Three-dimensional volume-rendered CTA of the heart and great vessels demonstrating a large inferobasal LV aneurysm, markedly dilated RCA aneurysm with fistulous drainage into the LV, and dilated ascending aorta. This rendering illustrates the spatial relationship of the aneurysms with the adjacent cardiac structures. CTA = computed tomography angiography; LV = left ventricle; RCA = right coronary artery.

History of Presentation

A 65-year-old man with hypertension and presumed cardiomyopathy (prior left ventricular [LV] ejection fraction: ∼40%) collapsed near the Grand Mosque during pilgrimage. Bystanders initiated cardiopulmonary resuscitation, and emergency medical services arrived promptly, documenting ventricular tachycardia (VT) cardiac arrest. He received 3 direct current shocks, intravenous amiodarone, and was intubated and sedated on site.

Take-Home Messages

• •Multimodality imaging is essential for diagnosing rare coronary anomalies.
• •Patient autonomy can override guideline-driven recommendations.

On arrival to Al-Haram Hospital (a peripheral non–percutaneous coronary intervention facility), electrocardiogram (ECG) showed diffuse ST-segment depression with ST-segment elevation in aVR, raising suspicion of left main or multivessel coronary artery disease. With no immediate percutaneous coronary intervention capability available and given high-risk ECG findings consistent with ST-segment elevation myocardial infarction equivalent, fibrinolysis was administered per protocol using recombinant tissue plasminogen activator. Differential diagnoses at that time included left main coronary occlusion, massive pulmonary embolism, or acute coronary syndrome with arrhythmic complications.

After partial stabilization and completion of initial resuscitative measures, the patient was transferred to our tertiary cardiac center for advanced evaluation and management. On arrival, he remained intubated and sedated and required norepinephrine to maintain hemodynamics.

Past Medical History

The patient had longstanding hypertension and a reported diagnosis of cardiomyopathy. No prior interventions or coronary imaging were documented.

Differential Diagnosis

Given the patient's presentation with cardiac arrest and ischemic ECG changes, differential considerations included acute left main or 3-vessel coronary artery disease, ventricular tachyarrhythmia secondary to ischemia, pulmonary embolism, and structural cardiac complications such as aneurysm or fistula.

Investigations

Initial laboratory evaluation revealed acute kidney injury (serum creatinine 2.1 mg/dL), transaminitis (aspartate aminotransferase: 540 IU/L, alanine aminotransferase: 480 IU/L), lactic acidosis (lactate: 4.9 mmol/L), coagulopathy (international normalized ratio: 2.7), and elevated troponin.

The timeline for imaging studies was as follows:

• •Day 1: Transthoracic echocardiography (TTE) showed preserved LV ejection fraction (>60%), no regional wall motion abnormalities, and dilation of the aortic root (52 mm at the sinuses of Valsalva, 45 mm at the sinotubular junction). A hypokinetic inferobasal segment with outward bulging consistent with LV aneurysm was noted. No pericardial effusion or significant valvular abnormalities were observed (Figure 1).
• •Day 2: Coronary computed tomography angiography (CTA) demonstrated a giant right coronary artery (RCA) aneurysm with maximal diameter of 42 mm, involving the mid to distal RCA, with a calcified wall and no ostial obstruction. A fistulous communication was clearly seen arising from the aneurysmal RCA and draining directly into the inferobasal LV cavity, without any intervening chamber. There was no evidence of intracavitary thrombus within the aneurysm. A true inferobasal LV aneurysm was also noted, measuring approximately 3.2 × 2.1 cm, with intact wall continuity and transmural thinning involving all myocardial layers. No signs of pseudoaneurysm (ie, wall rupture or narrow-necked sac) were seen. Ascending aortic dilation (49 mm) was also observed (Figure 2).
• •Day 3: Coronary angiography confirmed normal left main and left coronary arteries. The RCA was markedly aneurysmal, with sluggish contrast flow and opacification of the fistulous tract into the LV cavity (Video 1). No significant coronary stenoses were noted.

Figure 1.

Transthoracic Echocardiography

(A) Parasternal long-axis view showing aortic root dilation. (B) Apical 3-chamber view demonstrating the inferolateral left ventricular aneurysm.

Figure 2.

Computed Tomography Angiography

(A) CTA showing giant RCA aneurysm (42 mm) with fistulous drainage into the LV, (B) sagittal section demonstrating the inferolateral LV aneurysm that involve all layers (true aneurysm), (C) transverse cut showing the point of fistulation between the RCA and LV in addition demonstrating the aneurysmal segment. CTA = computed tomography angiography; LV = left ventricle; RCA = right coronary artery.

Cardiac magnetic resonance imaging was recommended to further characterize myocardial viability and clarify the anatomy of the aneurysm and fistula. However, the study was not performed because of patient refusal and early discharge against medical advice.

The diagnosis of a true LV aneurysm was based on CTA findings of full-thickness myocardial involvement, preserved epicardial continuity, and the absence of a narrow neck consistent with postinfarction true aneurysm morphology.

Management

The patient was initially stabilized with antiarrhythmic therapy and vasopressor support and subsequently extubated. Despite medical optimization, he experienced episodes of nonsustained VT, prompting readmission to the coronary care unit. As secondary prevention, an implantable cardioverter-defibrillator was recommended after multidisciplinary evaluation, but this was ultimately declined by the patient.

A full multidisciplinary team discussion was held involving cardiac surgery, interventional cardiology, imaging specialists, and electrophysiology. Percutaneous closure was deemed unsuitable given the complex fistula anatomy, specifically, the broad-necked connection of the aneurysmal RCA to the inferobasal LV wall, the presence of extensive aneurysmal dilation with calcifications, and the lack of a discrete entry site for device deployment.

The surgical plan that was offered consisted of aneurysm resection with fistula closure and potential aortic repair under cardiopulmonary bypass. Perioperative risks included bleeding, ventricular arrhythmias, and possible low-output syndrome, especially given the underlying structural distortion and prior arrest.

The patient demonstrated full decisional capacity and, after detailed counseling on risks, benefits, and alternatives, declined both surgical and device-based therapy. The care team respected his autonomy and proceeded with a medical management plan consisting of the following:

• •Oral amiodarone to suppress ventricular ectopy.
• •Anticoagulation with apixaban instead of warfarin, to mitigate thromboembolic risk from the aneurysmal segment, with better safety profile in the context of variable international normalized ratio control and recent bleeding risks.

Outcome and Follow-Up

The patient remained hemodynamically stable with no recurrence of sustained ventricular arrhythmias during hospitalization. After multidisciplinary evaluation, he declined both surgical repair and secondary-prevention implantable cardioverter-defibrillator placement after detailed counseling and assessment of decision-making capacity. A structured medical and surveillance plan was initiated upon discharge.

Discharge medications included:

• •Amiodarone 200 mg once daily for arrhythmic suppression
• •Apixaban 5 mg twice daily (preferred over warfarin because of fixed dosing and lower monitoring burden)
• •Bisoprolol 2.5 mg once daily for beta blockade and rhythm control

The surveillance plan was as follows:

• •ECG monitoring: weekly 24-hour Holter monitor for 3 months, then symptom-triggered event monitoring
• •Imaging follow-up: CTA every 6 months to monitor aneurysm dimensions and fistula stability; TTE every 6 months to assess LV function and aneurysm wall motion
• •Anticoagulation: annual renal and hepatic panel to reassess apixaban suitability

Despite the complexity of the findings and guideline-based recommendations for surgical and device-based interventions, the patient opted for discharge against medical advice. He later traveled to his home country.

Discussion

Coronary artery aneurysms are defined as dilatations exceeding 1.5 times the diameter of the adjacent normal coronary segment. Giant aneurysms (>20 mm) are extremely uncommon, with an angiographic prevalence of <0.02%.¹ The RCA is the most frequently affected vessel, accounting for approximately 40% of reported cases.^2,3 Coronary artery fistulas are abnormal connections between a coronary artery and a cardiac chamber or great vessel. Most are congenital and drain into the right atrium or pulmonary artery. In a large review, over 90% of coronary artery fistulas drained into right-sided chambers, while fewer than 3% terminated in the LV, making LV drainage exceptionally rare.⁴

The coexistence of a giant RCA aneurysm with a direct fistulous connection to the LV is therefore exceedingly unusual. Its concurrence with a true LV aneurysm and ascending aortic dilatation adds further structural complexity. Diao et al⁵ reported a similar case of a ∼56-mm RCA aneurysm directly communicating with the LV, also associated with LV enlargement and aortic dilatation.³ In our patient, the out-of-hospital VT arrest likely reflected an arrhythmogenic substrate arising from ischemia, mural thrombus, or conduction disturbance caused by distortion of the inferobasal myocardium. The true LV aneurysm, characterized by thinning and fibrosis with preserved wall continuity, was probably a sequela of prior transmural infarction.⁶

In this case, multimodality imaging was indispensable for defining the extent and relationship of the anomalies. TTE confirmed preserved systolic function and aortic root dilatation, whereas coronary CTA provided detailed visualization of the RCA aneurysm and its fistulous trajectory into the LV. Coronary angiography excluded left-sided obstructive disease and confirmed the presence of the RCA-LV communication.

According to the 2018 American Heart Association/American College of Cardiology guidelines, management of anomalous RCA with high-risk features such as ischemia or arrhythmia is individualized. Surgical intervention carries a Class IIa recommendation for symptomatic patients with arrhythmic events such as VT, and Class IIb recommendation for asymptomatic individuals with high-risk anatomy.⁷ In our patient, the coexistence of a giant RCA aneurysm, LV fistulous connection, and prior VT arrest would ordinarily support surgical correction.

However, refusal of surgery despite clear indications underscores an ethical and clinical challenge: balancing anatomic risk with patient autonomy. Given the rarity of such presentations, evidence-based guidance is limited, and management decisions must rely on individualized assessment within a multidisciplinary framework.

Pragmatic principles derived from this case include early recognition of aneurysmal and fistulous anatomy in atypical ischemic presentations, confirmation of “true” aneurysm morphology through multimodal imaging, comprehensive risk stratification that incorporates arrhythmic events and aneurysm size, and shared decision-making when guideline-recommended interventions are declined. Structured surveillance and long-term follow-up should therefore form the cornerstone of conservative management in these exceptional scenarios.

Conclusions

This case demonstrates a nearly unprecedented triad of a giant RCA aneurysm, coronary-LV fistula, and true LV aneurysm, presenting as cardiac arrest. It emphasizes the diagnostic value of multimodality imaging and the ongoing challenges in management of rare anomalies where guidelines are limited and patient preference plays a decisive role.

Funding Support and Author Disclosures

The authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Appendix

Video 1

Coronary Angiography

Coronary angiography showing the aneurysmal RCA and its drainage pattern into the LV. CTA = computed tomography angiography; LV = left ventricle; RCA = right coronary artery; TTE = transthoracic echocardiography.