The case of a patient in whom hemodynamic and electrocardiographic studies using the occlusion test for coronary artery fistulas (CAF) were safely performed prior to catheter embolization is reported. A 1-year-old girl had a separate right coronary artery arising from a left single coronary artery that formed a significant coronary artery fistula to the right ventricle. Coronary steal by the large coronary artery fistula narrowed the left coronary artery. The right coronary artery branches could not be clearly identified due to an overlap with the fistula. Due to the long porous CAF, embolic procedures could cause serious complications. We confirmed the safety by performing an occlusion test of the CAF’s proximal blood vessels. Following total occlusion of the CAF for 10 minutes, pulmonary arterial pressure and aortic blood pressure were not significantly changed. No bradycardia, atrioventricular block, or ST changes were observed. Coil embolization treatment was performed safely. For patients with long distal CAF complicated with a single coronary artery, myocardial ischemia and conduction system disorders can be identified by performing the occlusion test before embolization.
Coronary artery fistula (CAF) has congenital and acquired coronary artery abnormalities. This abnormality accounts for 0.27–0.4% of all congenital cardiac defects. Congenital single coronary artery comprises about 0.04% of congenital cardiac anomalies [
The parents of the following patient have given their consent for the publication of this report.
A 1-year-old girl presented with continuous heart murmur. Chest radiography showed slight cardiomegaly (cardiothoracic ratio, 55%). Electrocardiogram showed sinus rhythm and no ST changes. Echocardiography showed a dilated left main coronary trunk artery (LMT) and a right coronary artery (RCA) entering a right ventricular fistula. Coronary computed tomography angiography (CTA) with three-dimensional volume rendering revealed the thick and torsional RCA originating from the left anterior descending coronary artery (LAD), with fistulous communication to the right ventricle via a large vessel (Figure
(a) 320-row coronary CTA. The single coronary artery view shows the anterior course of the separate right coronary artery coming off the LAD. This is the anterior view. (b) Selective coronary angiography of the LMT shows the LAD and the LCX with weak contrast effects and a CAF with “multiple caliber change” of the RCA to the right ventricle (arrowhead). (c) Occlusion test on the proximal site of CAF using an occlusion balloon (arrowhead). (d) Engaged microcatheter in the distal RCA and embolization using a detachable coil. (e) One year after coil embolization, selective LMT coronary angiography clearly distinguishes the contrast effect of the LAD and LCX, the sinus node branch branching from LCX (white arrow), and right ventricular branches from the proximal side of the RCA (asterisks). The proximal end of the coil-embolized CAF formed a thrombus and occluded (arrowhead). CAF: coronary artery fistula; CTA: computed tomography angiography; LAD: left anterior descending coronary artery; LCX: left circumflex coronary artery; LMT: left main coronary trunk artery; RCA: right coronary artery.
After this procedure, anticoagulation therapy was continued. In cardiac catheter examination one year after coil embolization, the contrast effect of the LAD and left circumflex coronary artery (LCX) increased, and each coronary branch was easy to distinguish. The residual shunt from the CAF did not have a contrast effect. The proximal end of the coil-embolized CAF formed a thrombus and occluded. However, there existed right ventricular branches from the proximal side of the RCA. The sinus node branch revealed branching from the LCX. The collateral vessels from the developed septal branch, LAD, and sinus node branch supplemented the peripheral areas of the RCA (Figure
Up to 57% of patients with a CAF also have another congenital cardiovascular anomaly [
CAF are classified as distal or proximal. The proximal type arises near the origin of the coronary artery. A short proximal segment of the feeding coronary artery may be dilated, but the distal end of the original coronary artery is thin. The original coronary branches responsible for blood flow steal are hard to identify. The distal type of CAF originates near the distal end of a branch coronary artery. The feeding coronary artery proximal to a distal fistula gives rise to coronary branches that supply the myocardium [
Therapies to close congenital CAF during childhood have been recommended to avoid complications such as myocardial ischemia, congestive heart failure, endocarditis, and aneurysmal dilatation [
A balloon occlusion test before coil embolization of a CAF is necessary to avoid complications, particularly when many coronary branches cannot be distinguished clearly in small pediatric patients [
In patients with CAF, the coronary artery branches sometimes cannot be identified due to the presence of blood flow steal. In such cases, myocardial ischemia and conduction system disorders can be identified by performing the occlusion test before embolization.
The authors declare that they have no conflicts of interest.