Left main coronary artery aneurysm

Clinical History

A 62-year-old man underwent CT coronary angiography following atypical chest pain with unremarkable blood enzymes and inconclusive stress echocardiography. He had elevated blood pressure, dyslipidaemia, and a family history of cardiovascular disease.

Imaging Findings

CT angiography showed a saccular aneurysm of the left main coronary artery. The left anterior descending artery (LAD) presented a plaque in the proximal part that determined a stenosis of 50% of the lumen. A noncalcified plaque was present in the distal part of the circumflex artery resulting in a stenosis of 50%.

Discussion

Coronary artery aneurysm (CAA) is defined as the presence of a segment of coronary artery with a diameter >1.5 times the adjacent normal section (in the case of left main coronary artery >1.5 times the diameter of the widest artery of the patient). The incidence of CAA is 1-5% of routine angiograms with a strong predominance in men. The proximal and mid segments of the right coronary artery are most frequently affected, followed by the proximal anterior descending and the circumflex arteries. Left main coronary aneurysms are extremely infrequent, occurring in only 0.1% of the population [1].
CAA can be “true” aneurysms or “false” aneurysms (pseudoaneurysms). In true aneurysms the vessel wall is composed of all its three layers, whereas in pseudoaneurysms there is a loss of wall integrity. Coronary artery aneurysms can also be classified as saccular (i.e. with transverse diameter greater than the longitudinal axis) or fusiform (the longitudinal axis is greater than the transverse diameter). Some coronary artery aneurysms are defined as giant when the maximal diameter exceeds 20mm in adults or 8mm in children [2].
Atherosclerosis is responsible for almost half of CAA cases, while other causes include congenital heart diseases, trauma, Ehlers-Danlos syndrome, Kawasaki disease, Marfan syndrome, Takayasu arteritis, polyarteritis nodosa, syphilitic aortitis, scleroderma, systemic lupus erythematosus, Behcet’s disease, and fibromuscular dysplasia. Dyslipidaemia, hypertension, smoking, hyperinsulinaemia, hyperhomocysteinaemia, and specific human leukocyte antigens (HLA) and RAS gene polymorphisms have been identified as risk factors for the development of CAA.
Coronary angiography is the gold standard for diagnosis. Multislice computed tomography, cardiac magnetic resonance imaging (MRI) and echocardiography can provide valuable anatomic information on coronary anatomy that is usually difficult to assess by conventional angiography [3].
The disease can be asymptomatic, but most cases manifest with effort angina, myocardial infarction, or sudden death. Studies have shown that areas of aneurysmal dilation are susceptible to spasm, thrombosis and spontaneous dissection, and thus are potential causes of myocardial infarction. Spasms, episodes of microembolisation, and disturbances of blood flow caused by the presence of aneurysms may cause angina.
Prognosis and treatment are determined primarily by the severity of concomitant obstructive coronary disease. In cases of isolated CAA, prognosis is better. Chronic antiplatelet therapy is the mainstay of treatment [4].

Differential Diagnosis List

Final Diagnosis

Aneurysm of left main coronary artery

URL:	https://www.eurorad.org/case/10564
DOI:	10.1594/EURORAD/CASE.10564
ISSN:	1563-4086