Coronary arterial fistulas

Abstract

A coronary arterial fistula is a connection between one or more of the coronary arteries and a cardiac chamber or great vessel. This is a rare defect and usually occurs in isolation. Its exact incidence is unknown. The majority of these fistulas are congenital in origin although they may occasionally be detected after cardiac surgery. They do not usually cause symptoms or complications in the first two decades, especially when small. After this age, the frequency of both symptoms and complications increases. Complications include 'steal' from the adjacent myocardium, thrombosis and embolism, cardiac failure, atrial fibrillation, rupture, endocarditis/endarteritis and arrhythmias. Thrombosis within the fistula is rare but may cause acute myocardial infarction, paroxysmal atrial fibrillation and ventricular arrhythmias. Spontaneous rupture of the aneurysmal fistula causing haemopericardium has also been reported. The main differential diagnosis is patent arterial duct, although other congenital arteriovenous shunts need to be excluded. Whilst two-dimensional echocardiography helps to differentiate between the different shunts, coronary angiography is the main diagnostic tool for the delineation of the anatomy. Surgery was the traditional method of treatment but nowadays catheter closure is recommended using a variety of closure devices, such as coils, or other devices. With the catheter technique, the results are excellent with infrequent complications.

Figure 1

1a shows a dilated fistula between the proximal right coronary artery and right atrium. Such a fistula is suitable for an occlusion device such as the Amplatzer duct occluder (Figure 1b).

Figure 2

2a shows a fistula between the proximal part of the right coronary artery and drains to the right atrium. There is a stenosis at the entry point into the right atrium. Such a fistula may be suitable for closure with coils or duct occluder type of device. In Figure 2b, the fistula has been closed with coils.

Figure 3

3a shows a very tortuous fistula between the left anterior descending coronary artery and the right ventricle. Such a fistula is suitable for controlled-release coils (3b) rather than devices.

Figure 4

4a shows a tortuous small fistula between the proximal right coronary artery and the pulmonary trunk, which has been closed with controlled-release coils (4b). Figure 4c shows a tortuous fistula between the left anterior descending coronary artery and the pulmonary trunk in the same patient, which has been closed also with controlled-release coils (4d).