Image Question-59

coronary-pulmonary artery fistula

What is the Cause of the Color Flow Jet Marked?

[A] PDA
[B] Rat tail sign
[C] Coronary artery fistula
[D] AP Window

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Echocardiographic assessment in parasternal view documented

• Dilatation of the pulmonary artery trunk
• Normal-sized right chambers.
• Doppler echocardiography identified continuous laminar flow
• Jet flow corresponding to the site of coronary fistula drainage

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Coronary Artery Fistula (CAF) – Overview

A coronary artery fistula is an abnormal connection between a coronary artery and a cardiac chamber, great vessel, or other vascular structure, bypassing the myocardial capillary network.

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Key Points:

Surgical ligation (especially if complex anatomy or failed percutaneous closure)

Etiology:

Congenital (most common) – due to abnormal embryonic development of coronary vasculature

Acquired – post-cardiac surgery, trauma, endomyocardial biopsy, or invasive coronary interventions

Common Sites of Origin:

• Right coronary artery (RCA) – most frequent
• Left anterior descending (LAD) artery
• Left circumflex (LCx) artery

Common Sites of Drainage:

• Right atrium
• Right ventricle
• Pulmonary artery
• Coronary sinus
• Less common – left atrium, left ventricle, superior vena cava

Pathophysiology:

Shunt from high-pressure coronary artery to low-pressure receiving chamber/vessel → coronary steal phenomenon → myocardial ischemia

Clinical Features:

• Often asymptomatic (especially small fistulas)
• Symptomatic cases: exertional angina, dyspnea, palpitations, fatigue, signs of heart failure, or continuous murmur
• Large fistulas may cause myocardial ischemia, arrhythmias, or heart failure

Complications:

• Myocardial ischemia (due to steal)
• Heart failure
• Endocarditis/endarteritis
• Arrhythmias
• Aneurysm formation and rupture

Diagnosis:

Echocardiography (especially TEE) – detects abnormal flow

Coronary angiography – gold standard for anatomic definition

CT coronary angiography – non-invasive detailed imaging

Treatment:

Small, asymptomatic – conservative follow-up

Symptomatic or large fistulas – closure by:

Catheter-based techniques (coil embolization, plug device)