Coronary artery fistula (CAF) is abnormal connection between coronary artery and cardiac chamber or great thoracic vessel with congenital forms being the commonest so far. Its prevalence (0.05–0.25%) has been reported previously by many authors based on retrospective analysis of large amount of coronary angiography studies performed to rule-out or to treat obstructive coronary artery disease [1, 2].
Different vessels of origin have been reported regarding CAF including left anterior descending (LAD) artery, left circumflex (LCx) and right coronary artery (RCA) in decreasing order, and different sites of termination were also described with cardiac chambers (coronary-cameral fistula) being the commonest most frequently into right ventricle, while superior vena cava drainage was documented in minority of patients [3].
Although coronary angiography is still considered the gold standard for diagnosis of atherosclerotic coronary artery disease, its use in CAF diagnosis is less preferable due to complex nature of CAF, lack of three-dimensional (3D) images which outline the course of CAF in relation to adjacent structures. Furthermore, the dilution of injected contrast material during coronary angiography by the shunting effect of large fistulae decreases image quality and interferes with accurate assessment of draining site, and here it comes the value of CT [4].
With increasing number of coronary CT angiography studies performed to rule-out obstructive coronary artery disease as well as the widespread availability of high-end CT scanners, the number of detected CAF is increasing even in asymptomatic individuals or those with atypical ischemic symptoms owing to high spatial and temporal resolution of recent CT scanners together with 3D reconstructions which facilitates the evaluation of CAF regarding site of origin, course, and termination [5].
The reported incidence of CAF in patients undergoing coronary CT angiography is higher than in those undergoing invasive coronary angiography as the latter is being replaced nowadays by multislice CT in those with low to intermediate risk of having coronary artery disease [6].
The purpose of this study was to know the prevalence of CAF among Egyptian population detected by routinely performed coronary CT angiography at our institution, and to further analyze different sites of origin and termination, and to correlate the CT findings with clinical symptoms and any associated cardiac abnormality detected at performed coronary CT study.