Teaching Case

A 33-year-old man complained of chest pain, mucous congestion and asthma for one month. Transthoracic echocardiography 10 years before revealed aortic insufficiency. He had a history of a serious reaction to penicillin, but no history of injury, previous surgery and atherosclerosis or any relevant family history.

X-ray showed an abnormal shadow on the left cardiac border.
Doppler echocardiography revealed a dilatation in the aorta and right coronary artery (RCA) (maximal transverse diameter: 22 mm) travelling along the atrioventricular groove, a 15 mm diameter fistula draining into the left ventricle, diastolic shunt by flow rate 350cm/s, enlargement of the left ventricle (LV) (65mm) and ejection fraction 61%.
Dual-source computed tomography (DSCT) angiography showed a coronary artery fistula (CAF) and aneurysmal dilatation originating from the RCA, the CAF having a fistulous connection to the LV, with the maximum diameter of aneurysmal dilatation being about 31 mm and the fistula 9 mm.
The aneurysmal dilatation compressing the right ventricle (RV) markedly enlarged the LV and the left anterior descending artery ran along the surface of the myocardium. The diameter of the ascending aortic lumen was 41mm, and the diameter of the aortic sinus about 44 mm.

Background: CAF is an abnormal connection between a coronary artery and any of the 4 chambers of the heart or any of the great vessels [2]. They most frequently originate in the right coronary artery, and the right cardiac chambers are the most common draining chambers [4], the drainage site being the pulmonary artery, RV, right atrium, LV and so on.
There are few reported cases of a coronary fistula with aneurysmal dilatation arising from the right coronary artery that had a fistulous connection to the left ventricles [1, 3, 5].
Clinical perspective: The fistula could be single or multiple; infants and children may be asymptomatic. Apart from symptoms of angina or infarction, there are no specific signs or symptoms of CAF, and it is found slightly more often in men.
Imaging techniques can provide a diagnosis and guide the therapeutic management.
Imaging perspective: Doppler echocardiography and computed tomography angiography are able to diagnose a CAF and aneurysmal dilatation arising from cardiac chambers and great vessels.
DSCT 3D imaging (Maximum Intensity Projection, Multiple Planar Reconstruction and Volume Rendering) can be intuitive and accurately display the structure and the branches of the coronary artery. Not only can it provide information regarding the location, size, shape, and number of fistulas, but also demonstrate the origin and drainage site. This was helpful for defining the range of the surgical procedure.
Outcome: Angina, congestive heart failure, myocardial infarction, and rupture are indications for surgery. Surgical techniques have shown excellent results.
Take Home Message, Teaching Points:
- Differential diagnosis of a right cardiac bulge in chest X-ray has to include right atrial enlargement.
- If a coronary artery fistula is suspected or diagnosed with Doppler echocardiography and computed tomography angiography, coronary tree study is mandatory.
- DSCT-Angiography represents an ideal, noninvasive imaging modality for the diagnosis of coronary artery malformations, complementing invasive coronary imaging.
- Aortic root aneurysms with aortic insufficiency and coronary fistulas with aneurysmal dilatation to the left ventricle are rarely reported, and rupture is a potential complication. Nowadays the first line treatment are surgical techniques.