Left circumflex coronary artery aneurysm with arteriovenous fistula to the coronary sinus presenting as acute coronary syndrome.

899 from the right or left anterior descending cor‐ onary artery; therefore, Cx fistulas are unique. A great majority of fistulas bypass the blood from the arterial to venous systems, such as the pulmo‐ nary artery, coronary sinus, superior vena cava, or right ‐sided heart chambers. Most patients re‐ main asymptomatic.1 Possible clinical presenta‐ tions of coronary fistulas include angina, myocar‐ dial infarction, heart failure symptoms, endocar‐ ditis, arrhythmias, and they are related with the size and location of a fistula.3 Of note, most pa‐ tients develop symptoms of myocardial ischemia in their fourth to sixth decade of life.4 Myocardi‐ al ischemia associated with coronary fistulas can be secondary or, less common, primary.4 Coronary steal syndrome was a possible expla‐ nation of angina in our patient. Potential compli‐ cations of coronary fistulas are aneurysmal remod‐ eling of drained artery, which was present in our patient, and rupture or thrombosis of the fistula. Coronary angiography is the gold standard for di‐ agnosing coronary fistula.1 Nevertheless, nonin‐ vasive methods such as color ‐flow Doppler ultra‐ sound, magnetic resonance imaging, and comput‐ ed tomography can be useful in diagnosis, as they show the exact shape and anatomy of arteriove‐ nous connections of fistulas.5 Treatment is recom‐ mended only for symptomatic patients, and pos‐ sible options are surgical or transcatheter fistula closure. Surgical treatment was the most common technique until the introduction of transcatheter techniques in carefully selected patients with suit‐ able anatomy of the fistula, namely, accessible with a closure device and with no other indications for surgery.1 Coronary artery fistulas, although rare, should be considered in a differential diagnosis of chest pain, particularly in young patients without known risk factors of atherosclerosis. A 61 ‐year ‐old Caucasian woman with a history of ischemic heart disease, hypertension, type 2 dia‐ betes, and hypercholesterolemia was admitted to the hospital due to unstable angina. Three months prior to hospitalization, an exercise treadmill test was performed showing a significant down sloping ST ‐segment depression of 1.5 mm in leads III, aVF, and V4–V6, at 7 metabolic equivalents of exercise with no chest pain. A physical examination was unremarkable, blood pressure was 130/75 mmHg, and the pulse rate was regular (66 bpm). An elec‐ trocardiogram on admission revealed inferolat‐ eral ST ‐segment depression with ST ‐segment el‐ evation in lead aVR, suggesting diffuse subendo‐ cardial ischemia. Routine blood test results were normal. The measurement of high ‐sensitivity car‐ diac troponin levels yielded negative results. Ur‐ gent transthoracic echocardiography showed no wall motion abnormalities with normal left ven‐ tricular ejection fraction of 65%. On a comput‐ ed tomography (CT) angiography, a fistula from the circumflex artery (Cx) to coronary sinus was suspected (FIGURE 1A–C). The coronary angiography confirmed a large fistula between an aneurysmat‐ ic Cx and the coronary sinus without coronary ar‐ tery stenosis (FIGURE 1D). After a heart team con‐ sultation, the patient was referred for a surgical fistula closure and then successfully operated on. One year after the surgery, a CT angiography ex‐ cluded any communication between the Cx and coronary sinus. After a 6 ‐year follow ‐up, the pa‐ tient is in good general condition without any symptoms of angina. Coronary arteriovenous fistulas are uncom‐ mon anomalies that are observed in 3 to 8 cases per thousand of coronary angiograms.1,2 Further‐ more, aneurysmal formation of the artery drained by the fistula is uncommon.1 Usually, fistula arises CLINICAL IMAGE