Discussion

Coronary artery fistulae are rare anomalies of the coronary tree, defined as abnormal communication between coronary arteries and vascular structures. According to the American Heart Association, the "Sakakibara" classification can be used to classify coronary artery fistulae. ^{Reference Reddy, Davies, Holmes, Schaff, Singh and Alli1} Several studies have demonstrated the incidence of coronary artery fistulae ranging from 0.05% to 0.9% in the general population ^{Reference Lim, Jung and Lee2} . Rare multiple coronary artery fistulae have also been reported in the literature. ^{Reference Lim, Jung and Lee2} The most common site of origin of coronary artery fistulae is the right coronary artery and the right atrium, pulmonary artery, and right ventricle being draining end points. ^{Reference Lim, Jung and Lee2} Whilst predominantly congenital (as in our case), coronary artery fistulae can also be acquired post-myocardial infarction or be iatrogenic post-endomyocardial biopsy or following percutaneous intervention. ^{Reference Fernandes, Kadivar, Hallman, Reul, Ott and Cooley3} Depending on the size of the coronary artery fistulae patients can often be asymptomatic, thus be incidentally found during cardiac investigations. Large coronary artery fistulae can manifest with chest pain, shortness of breath, fluid overload, and a systolic crescendo–decrescendo murmur secondary to severe shunting. In 2018, the American Heart Association published guidelines on the investigation and management of coronary artery fistulae with an emphasis on multidisciplinary medical and surgical joint partnership. ^{Reference Stout, Daniels and Aboulhosn4} However, in continental Europe, coronary artery fistulae are not specifically addressed in the international guidelines on adult CHD from the European Society of Cardiology. ^{Reference Baumgartner, Bonhoeffer and De Groot5} Initial step of echocardiography is essential in evaluating the ventricular size, any regional wall abnormalities, shunting and left ventricular systolic function. Following this, coronary angiography is an ideal modality to look at coronary artery disease and fistulae, however CT coronary angiogram is considered to be the superior non-invasive modality as it allows enhanced visualisation of the coronaries with high-resolution and three-dimensional volume rendering. ^{Reference Stout, Daniels and Aboulhosn4} Percutaneous closures of coronary artery fistulae involve occlusion coils, detachable balloons, and stents. ^{Reference Stout, Daniels and Aboulhosn4} The question to opt for surgical or percutaneous management involves an multidisciplinary team approach to assess the anatomy and physiology of the coronary artery fistulae, the patient’s co-morbidities, and perioperative risk. For example, fistulae that are symptomatic, large, and complex are candidates for surgical management, whereas fistulae that is proximal, non-tortuous, and in older frail patient’s, percutaneous management can be opted for. ^{Reference Stout, Daniels and Aboulhosn4} As our patient was relatively young with no comorbidities, both options for surgical and percutaneous management were given, of which after discussion with the patient percutaneous option was opted for.