A Native Coronary Ventricular Fistula

Coronary anomalies, like coronary arteriovenous fistulae, where the coronary arteries communicate abnormally with the cardiac chambers, can be a result of congenital or acquired pathophysiology. They account for about 0.002% of the general population. 

Case Report

A 63-year-old female presented to the hospital after experiencing 3 days of intermittent, substernal chest pain, worse with exertion and improving with rest. On the day of her presentation to the hospital, the patient developed 6 out of 10 pressure-like chest pain, radiating to bilateral shoulders, and associated with nausea and lightheadedness. Her past medical history was significant for tobacco abuse and hypertension. She smoked about 10 cigarettes daily and had a 15-pack-year history. She denied any contributory family history of premature coronary artery disease. She was allergic to hydrochlorothiazide and has been on lisinopril for treatment of hypertension. Her clinical examination was unrevealing, with temperature 37.5°C, heart rate 88 bpm, respiratory rate 18/min, blood pressure 135/75, and oxygen saturation 99% on 2L oxygen via nasal cannula. Cardiovascular examination revealed S1-S2 normal, S3-S4 absent, no murmur, rub or gallop appreciated. Point of maximal impulse (PMI) minimally displaced laterally, pulses normal bilaterally. No jugular venous distention (JVD). Extremities with trace pedal edema. The examination was otherwise normal. 

An electrocardiogram (EKG) showed nonspecific inferior T-wave changes. Chest x-ray was normal. Blood work was predominantly normal, with cardiac enzymes within normal range. An echocardiogram revealed a preserved ejection fraction (EF) with EF of 70% and mild left ventricular hypertrophy, no definitive regional wall motion abnormality, and no identifiable shunt with Doppler, which was reviewed again after cardiac catheterization.  

The patient was admitted to the telemetry unit for chest pain evaluation. As her chest pain presentation was typical with nonspecific changes in her EKG, history of tobacco abuse and hypertension, she underwent non-emergent cardiac catheterization for further evaluation. No significant coronary artery disease was visible, but a fistula originating from the distal right coronary artery (RCA) and emptying into the left ventricle cavity was revealed. The fistula was not large enough to be coiled or ligated. No coronary intervention was pursued. On further review of the echocardiogram, no shunt was identified. There was no plan for surgical intervention. The patient was medically managed with metoprolol. She did not have return of her symptoms thereafter. She was discharged home after 2 days. In follow-up, she was doing well, was without issues, and was able to exercise several times per week without exertional angina. 

Discussion

Coronary artery to ventricular cavity fistula is an entity first identified by cardiac catheterization. A spontaneous or congenital fistula should attempt to be distinguished from a secondary or acquired communication, such as a fistula arising following cardiac surgery, myocardial biopsy, or myocardial infarction. An origin from the right coronary artery is more common than left (55% vs 35%, respectively) with the receiving structure being most commonly the right ventricle, right atrium, or pulmonary artery space (45%, 25%, or 15-20%, respectively).

The left ventricle is very frequently the receiving structure of a coronary artery fistula. Secondary coronary ectasia may occur with the bleeding vessel as it dilates over time (contrary to micro fistulas), with shunting of coronary flow, sometimes resulting in a steal phenomenon as well as volume overload, if a very large shunt empties into the left ventricular cavity. However, it is unlikely for oximetry to reveal evidence of significant shunt. On nuclear cardiac perfusion imaging, reversible ischemia may be present, thought to be possibly due to steal phenomenon, and the size of the reversible ischemia will be based on the amount of shunt. Coronary artery fistulae may also be identified by more modern imaging studies such as magnetic resonance imaging (MRI), computed tomography (CT), or Doppler echocardiography.

Management is controversial when asymptomatic. Medical treatment includes beta-blockade, with surgical therapy aimed at those with symptoms, in which coil embolization or ligation may be considered. Bacterial endocarditis prophylaxis is often recommended.

This report illustrates a remarkable case of a native right coronary to left ventricular fistula. It is important to identify those patients with a coronary fistula, as it may impact management, although given the infrequency at which this entity is seen, approach to treatment is controversial. History and physical exam is neither sensitive nor specific. Our patient had minimal shunting with no significant reversible ischemia and was successfully medically managed with resolution of symptoms.

References

1. Angelini P. Coronary artery anomalies—current clinical issues: definitions, classification, incidence, clinical relevance, and treatment guidelines. Tex Heart Inst J. 2002; 29(4): 271-278.
2. Cabamus B, Khan N, Shammas R. Large spontaneous coronary artery-to-right ventricular fistula. J Invasive Cardiol. 2006 Dec; 18(12): E288-291.
3. López-Candales A, Kumar V. Coronary artery to left ventricle fistula. Cardiovasc Ultrasound. 2005 Nov 8; 3: 35.
4. Challoumas D, Pericleous A, Dimitrakaki IA, Danelatos C, Dimitrakakis G. Coronary arteriovenous fistulae: a review. Int J Angiol. 2014 Mar; 23(1): 1-10. doi: 10.1055/s-0033-1349162. 

The authors can be contacted via Dr. Nissi Suppogu at nissi.suppogu@hhchealth.org.