AJR 2004; 182:617-618
© American Roentgen Ray Society
MDCT of a Malignant Anomalous Right Coronary Artery
Cameron Hague1,
Gordon Andrews and
Bruce Forster
1 All authors: Department of Radiology, University of British Columbia, 2211
Wesbrook Mall, Vancouver V6J 3R3, BC, Canada.
Received March 18, 2003;
accepted after revision July 23, 2003.
Address correspondence to G. Andrews
(gandrews{at}vanhosp.bc.ca).
Introduction
Knowledge of coronary artery anatomy is becoming increasingly important to
radiologists. Coronary artery calcification scoring has been proven to be an
independent risk factor in prediction of hard coronary events (myocardial
infarction and cardiac death) in asymptomatic persons, with risk ratios that
may exceed traditional Framingham risk factors
[1]. Coronary CT angiography is
poised to become a clinical reality in augmenting or replacing diagnostic
catheter angiography [2].
Knowledge of cross-sectional anatomy of the coronary arteries and their
variants is critical for accurate diagnosis, especially because some variants
are associated with sudden death.
The right coronary artery typically arises from the right sinus of
Valsalva. It courses anteriorly between the pulmonary trunk and the auricle of
the right atrium before entering the right atrioventricular groove. The origin
and course of the right coronary artery are not always as described, with
various congenital anomalies of the right coronary artery documented
[3,
4]. Among these anomalies is a
right coronary artery that arises from the left sinus of Valsalva and then
courses between the pulmonary trunk and the aorta before continuing within the
right atrioventricular groove. Such a variant has been called
"malignant" because it is associated with sudden death
[5]. In this article we
describe a patient with an anomalous right coronary artery that was an
incidental finding on CT.
Case Report
A 73-year-old man presenting with chronic obstructive pulmonary disease and
hemoptysis underwent high-resolution CT to assess for bronchiectasis (1-mm
slice thickness every 10 mm, 120 kVp, 300 mA/sec). On CT, we saw an anomalous
right coronary artery arising from the left sinus of Valsalva and coursing
between the aortic root and the pulmonary trunk
(Fig. 1). Incidental note was
made of extensive calcification of the left anterior descending coronary
artery.
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Fig. 1. —73-year-old man with anomalous right coronary artery. CT scan
shows anomalous right coronary artery (thin arrows). Note that left
anterior descending coronary artery is heavily calcified (thick
arrow).
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The patient was not considered a candidate for catheter angiography because
of preexisting health problems and has not experienced any negative outcome
thus far.
Discussion
Congenital coronary artery anomalies have an incidence of 1–2% in
patients undergoing coronary artery catheterization
[3,
4]. Anomalies of the right
coronary artery specifically are seen in 0.2–0.5% of the population
[3]. The most common right
coronary artery anomaly is, as described previously, with the origin from the
left sinus of Valsalva coursing between the aorta and pulmonary trunk
[3]. Other anomalous right
coronary artery origins exist, including those from the pulmonary trunk, the
distal ascending aorta, and the left main coronary artery
[3,
4].
Before 1982 an anomalous right coronary artery arising from the left sinus
of Valsalva and coursing between the aortic root and pulmonary trunk was
considered to have a benign outcome. However, more recent evidence has been
reported that suggests a high correlation between this anomaly and increased
mortality [3,
4]. The incidence of sudden
death is estimated at 25–40% and is associated with exercise in half of
reported cases [4]. The
mechanism is not entirely clear. Theories include a slitlike ostium, acute
angulation at the origin, and compression of the vessel between the aorta and
pulmonary trunk [3,
4].
Catheter angiography remains the current gold standard for the assessment
of stenosis in coronary atherosclerotic disease and has an added advantage
with its interventional capability. However, it can be inaccurate in the
diagnosis of coronary artery anomalies. A number of studies have documented
subsequent revision of angiographic diagnoses based on information from
cross-sectional imaging studies
[2,
6]. Difficulties with catheter
engagement of the anomalous vessel can lead to the erroneous assumption that
the vessel is occluded [7].
Also, limitations of coronary angiography in the visualization of noncoronary
cardiac anatomy can lead to misinterpretation of the proximal course of the
coronary vessels [7].
Results of recent studies examining the use of MRI and CT in the detection
of the proximal course of coronary artery anomalies have been promising
[2,
6,
8]. The accuracy of MRI with
ultrafast cardiac-gated sequences has been shown to rival the accuracy of
catheter angiography in the diagnosis of coronary anomalies in various studies
[6–8].
Imaging of coronary arteries has been described using both electron beam CT
and MDCT. The accuracy with which ultrafast contrast-enhanced CT can show the
proximal course of coronary artery anomalies and the sensitivity for detecting
coronary artery anomalies are similar to MRI
[2].
In conclusion, we describe a 73-year-old man with an anomalous right
coronary artery, arising from the left sinus of Valsalva and coursing between
the aortic root and the pulmonary trunk. This particular anomaly, termed
"malignant" by other researchers
[5], has an associated high
incidence of sudden death and therefore is a lesion with which to be familiar.
This case report shows that unenhanced MDCT can depict such coronary artery
anomalies.
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Introduction
Case Report
