Coronary Fistula Complications
Coronary artery fistulas can cause acute myocardial infarction, paroxysmal atrial fibrillation, ventricular arrhythmias, heart failure, myocardial ischemia, endarteritis, dissection, rupture, and progressive chamber enlargement—with symptomatic fistulas requiring transcatheter or surgical closure. 1, 2
Natural History and Clinical Complications
Coronary fistulas arise from the right or left coronary artery and most commonly drain into the right atrium, right ventricle, or pulmonary artery. While most patients remain asymptomatic in childhood, symptom frequency increases substantially in adulthood 1.
Life-Threatening Complications
- Thrombosis within the fistula (rare but serious): Can precipitate acute myocardial infarction, paroxysmal atrial fibrillation, and ventricular arrhythmias 1
- Myocardial ischemia and infarction: Results from coronary steal phenomenon as blood bypasses normal myocardial capillary beds 2
- Endarteritis: Infectious complication requiring closure 2
- Dissection and rupture: Documented risks, particularly with increasing fistula size 2
- Progressive chamber enlargement: Chronic volume overload leads to ventricular dysfunction 2
- Heart failure: From chronic left-to-right shunting and ventricular remodeling 2
Progressive Nature
Small fistulas may slowly enlarge with advancing age due to changes in systemic blood pressure and aortic compliance. Increasing fistula size correlates with increased abnormalities of coronary flow, chest pain, decreased life expectancy, and rupture risk 2.
Evaluation Strategy
Initial Assessment
When a continuous murmur is present, define its origin using echocardiography, MRI, CT angiography, or cardiac catheterization 2.
Ongoing Surveillance
For small, asymptomatic fistulas: Clinical follow-up with echocardiography every 3-5 years to monitor for symptom development, arrhythmias, progressive size increase, or chamber enlargement 2.
Pre-Intervention Workup
Transcatheter delineation of the fistula course and access to distal drainage must be performed in all patients with audible continuous murmur and recognized coronary fistula 2.
Treatment Indications
Mandatory Closure (Class I)
Close all large coronary fistulas regardless of symptoms via transcatheter or surgical route after complete anatomic delineation 2.
Close small to moderate fistulas when any of the following are present 2:
- Documented myocardial ischemia
- Arrhythmias (atrial or ventricular)
- Unexplained ventricular systolic or diastolic dysfunction
- Ventricular enlargement
- Endarteritis
Transcatheter occlusion is indicated for all symptomatic coronary artery fistulas 1.
Reasonable to Close (Class IIa)
Transcatheter occlusion is reasonable for moderate or large coronary fistulas without clinical symptoms 1.
Do Not Close (Class III)
Transcatheter device occlusion is not indicated for clinically insignificant fistulas (e.g., normal-sized cardiac chambers) 1.
Procedural Complications
Transcatheter Closure Risks
Complications of transcatheter coil or device embolization include 1:
- Incomplete occlusion with residual shunting: Most common complication
- Myocardial ischemia: If a more distal coronary artery is inadvertently occluded
- Device embolization: Coil migration to right heart or pulmonary artery requiring retrieval
- Thrombus formation: In venous channels or collecting system
- Device malposition: Requiring repositioning or retrieval
Critical Procedural Pitfall
Care must be taken to avoid occlusion of nearby non-fistulous coronary branches, as this can cause iatrogenic myocardial infarction 1.
Reassuring Long-Term Data
Late recanalization or endarteritis has not been reported after coil embolization of coronary artery fistulas 1.
Procedural Requirements
Transcatheter closure must be performed only in centers with expertise in such procedures 2.
Surgeons with training and expertise in congenital heart disease should perform operations for coronary fistula management 2.
Post-Intervention Surveillance
Patients with coronary fistulas require intermediate and long-term follow-up even after repair, as they may retain large, patulous epicardial conduits with thin-walled, ectatic coronary arteries 2.