Prevalence and types of coronary artery fistulas detected with coronary CT angiography.

OBJECTIVE: The prevalence of coronary artery fistula (CAF) based on coronary angiographic findings has been reported. However, the number of incidentally found CAFs is increasing as coronary CT angiography (CTA) has become popular. The purpose of this study was to determine the prevalence and types of CAFs detected with coronary CTA.
MATERIALS AND METHODS: Between March 2009 and November 2011, 6341 patients underwent coronary CTA at one institution. The prevalence of CAF was retrospectively evaluated, and the morphologic features were analyzed, including vessel of origin, drainage site, size, and presence of an aneurysmal sac. We also analyzed cardiac and pulmonary findings.
RESULTS: Among 6341 patients, 56 (0.9%) patients had CAF. The types of CAF detected, in decreasing frequency, were coronary to pulmonary artery fistula (43 cases [76.8%]), coronary to bronchial artery fistula (five cases [8.9%]), coronary artery to cardiac chamber fistula (five cases [8.9%]), combined coronary to pulmonary and coronary to bronchial artery fistula (two cases [3.6%]), and coronary artery to superior vena cava fistula (one case [1.8%]). Lung parenchymal or vascular anomaly was more frequently noted in coronary to bronchial artery fistulas, combined coronary to pulmonary and coronary to bronchial artery fistulas, and coronary artery to superior vena cava fistulas than in coronary to pulmonary artery and coronary artery to cardiac chamber fistulas.
CONCLUSION: The prevalence of CAF at coronary CTA was 0.9%, which is higher than the known prevalence based on conventional angiographic findings (0.05-0.25%). Furthermore, the most common type of CAF in this study was coronary to pulmonary artery, whereas coronary artery to ventricle fistula was previously considered the most common type in studies conducted with conventional angiography. Coronary CTA is a useful, noninvasive imaging modality for the detection of CAF.