Discussion.
CAAs are rare cardiac anomalies, with an incidence rate of
<1% and are often misdiagnosed as sickle cell crisis in
patients with a history of sickle cell disease or trait (3). With the
exception of a coronary artery traversing between the aorta and
pulmonary trunk potentially causing sudden death at a young age due to
extrinsic coronary occlusion, CAAs usually carry minimal clinical
significance. In a study conducted by Taylor et al., it was demonstrated
that 25% of CAAs culminated in asymptomatic sudden death, with
autopsies showing evidence of repetitive episodes of minor myocardial
infarctions - diffuse necrosis and myocardial fibrosis (4). Obstruction
of blood flow can be due to multiple causes - 1) obstruction of the
coronary ostium due to slit-like morphology, 2) the aorta and pulmonary
trunk compressing the right coronary artery and 3) aortic and pulmonary
arterial distension leading to stretching and increased tension of the
right coronary artery (5). CT coronary angiogram is advantageous over
ECG and conventional coronary angiography as it detects not only the
extent and site of stenosis, but also the ectopic origin and course of
the anomalous coronary artery. An increase of CAAs have been diagnosed
since the advent of CT coronary angiography (6).