Coronary artery fistula with myocardial infarction due to steal syndrome

Abstract

Sirs: Coronary artery fistulas are anomalous connections between a coronary artery and a cardiac chamber or great vessel [1]. They are rare abnormalities with a reported incidence of 0.13–0.18% of patients undergoing coronary angiography [2, 3]. The majority of coronary artery fistulas are congenital in origin, but they have been reported as acquired complications of chest trauma and surgery also. Most of them are diagnosed incidentally in asymptomatic patients, but depending on shunt volume, congestive heart failure can develop [1]. Furthermore, myocardial ischemia due to a ‘steal’ from the adjacent myocardium has been reported [4–12], but true existence of this phenomenon is a controversial issue [13]. We present the case of a young female with a large coronary artery fistula originating from the proximal left anterior descending artery (LAD), and evidence of a coronary steal syndrome is provided by fractional flow reserve (FFR). A so far healthy 36-year-old female without cardiovascular risk factors presented in our emergency department with sudden onset chest pain following a long exhausting motorbike trip. Physical examination was unremarkable, and no cardiac murmur was audible. Baseline electrocardiogram showed T inversions in the anterior leads, and the cardiac biomarkers were elevated with a peak high sensitive Troponin T of 0.55 lg/l and a peak creatine kinase of 623 U/l. Subsequent left heart catheterization ruled out coronary artery disease, but a large coronary artery fistula originating from the proximal LAD draining into to the pulmonary trunk was found (Fig. 1). Ventriculography showed a hypokinesis of the anterior segments distal to the origin of the fistula, and magnetic resonance tomography revealed a late enhancement pattern of subendocardial myocardial infarction (Fig. 2). Hypothesizing a coronary steal syndrome due to the fistula, a second procedure with left and right heart catheterization was performed. Hemodynamic and oximetric measurements revealed a systemic blood flow (QS) of 6.0 l/min and a pulmonary blood flow (QP) of 6.7 l/min, leading to a relatively small calculated left-to-right shunt of 0.68 l/min (QP/QS = 1.12), and pulmonary artery pressure was in normal range. FFR in the distal LAD was 0.78 under maximal hyperemia, raising to 0.95 while temporary experimental occlusion of the fistula using a 3.0/15 mm standard balloon catheter. In consideration of this evidence of steal syndrome, coil embolization of the fistula was performed in the same procedure, using 2 Detach embolization coils (Cook Medical, Bloomington, IN, USA) [2–2 and 2–4 (diameter in mm–length in cm)] in each of the two main branches and another two coils (3–4 and 3–6) in the bifurcation of the fistula (Fig. 1). Finally, a FFR of 1.0 was measured in the distal LAD. The patient was discharged free of symptoms the following day. At 3-month follow-up, the patient was free of symptoms, and echocardiography revealed complete recovery of left ventricular function. A coronary artery fistula is a rare but not an exceptional finding on a routine coronary angiogram. Small fistulas need no specific treatment, but if they are hemodynamically important, elective closure is recommended. Coil embolization of coronary artery fistulas is considered as a safe and effective treatment [14–16], and the aim of the procedure is to achieve complete occlusion at as distal a location as possible in the fistulous vessel [1]. Based on case reports, coronary artery fistulas are considered as a rare cause of myocardial infarctions that T. Harle (&) K. Kronberg A. Elsasser Department of Cardiology, Heart Center, Klinikum Oldenburg gGmbH, Rahel-Straus-Str. 10, 26133 Oldenburg, Germany e-mail: t.haerle@gmx.de