Split right coronary artery in CT angiography

Clinical History

A 44-year-old male patient with history of chest pain referred to the radiology department for an evaluation of coronary arteries.

Imaging Findings

The right coronary artery (RCA) originates normally from the right coronary cusp. Right coronary artery (RCA) bifurcates (just after its origin from the right cusp with main trunk) into anterior and posterior branches. The anterior branch is coursing over the free wall of the right ventricle and the posterior branch travels in the right atrioventricular groove. These vessels are small in caliber, however no atherosclerotic plaque nor segmental stenosis is identified. The posterior descending artery was a continuation of the posterior branch of RCA and had no significant disease.
No abnormality was identified in the left coronary artery.

Discussion

Background:

In this anomaly the right coronary artery consists of two separate branches coursing very closely together in the atrioventricular groove, for at least half of its entire length [1, 6].
Split right coronary artery is classified as class B (Anomalies of intrinsic coronary arterial anatomy) [3].
Split right coronary artery is one of the rare congenital anomalies and the common coronary anomaly. The prevalence of CT-defined split RCA is reported 0.07% [1-3, 5].
Congenital coronary artery anomalies are diagnosed in approximately 0.6%-1.3% of adult patients undergoing coronary angiography. Split right coronary artery was reported in (1.2%) of the right coronary anomalies [2].
This entity is also known as “double right coronary artery”, “duplicated right coronary artery”, “dual right coronary artery”, “supernumerary right coronary artery” and “split right coronary artery” [1, 2].

Clinical Perspective:

Most patients with split right coronary artery are usually asymptomatic and no abnormality is detected on physical examination, but they are the second most important cause of sudden death in apparently healthy young athletes [1, 3, 4].
There are no specific electrocardiographic alterations that indicate a diagnosis of coronary anomaly. The presence of abnormalities suggestive of ischaemia or cardiac arrhythmia in children or young adults can raise suspicion and prompt other diagnostic examinations [3].
The possible manifestations include not only sudden cardiac death but also chest pain, dyspnoea, palpitations, angina pectoris, dizziness, and syncope [4].

Imaging Perspective:

Noninvasive evaluation of coronary arteries by CT angiography is now a widely used imaging modality of evaluating the coronary arteries, both for detecting atherosclerotic disease and identifying anomalies of origin or course, and several studies have demonstrated its accuracy. In CT coronarygraphy no direct catheterization is needed.
CT coronarygraphy provides better characterization of the origin of coronary arteries when selective characterization of the vessels is difficult, or even impossible, by invasive coronary angiography [3, 6].
Recent advances in cardiac CT angiography have enabled more and better information to be obtained, while requiring ever smaller radiation doses [3].
Invasive coronary angiography has been the modality of choice for evaluation of coronary artery disease for nearly 5 decades. However, noninvasive coronary imaging with computed tomography has quickly developed, and initial experience with multislice CT coronary angiography has been reported [8].

Outcome:

As the majority of split right coronary artery patients are asymptomatic and are incidentally diagnosed, no treatment is needed. The prognosis depends on the diameter, atherosclerotic plaques and associated coronary anomalies. [7]

Differential Diagnosis List

Final Diagnosis

Split right coronary artery without atherosclerotic plaque or segmental stenosis.

URL:	https://www.eurorad.org/case/12908
DOI:	10.1594/EURORAD/CASE.12908
ISSN:	1563-4086