Teaching Case

A 10-year-old boy with known Kawasaki disease came to the cardiology department for evaluation. He did not have any chest pain or cardiac symptoms. There was no history of any cardiac intervention. A screening CT coronary angiography was done for presence of any coronary aneurysms.

CT coronary angiography revealed fusiform aneurysmal dilatation of proximal Left Anterior Descending (LAD) artery and left circumflex artery. There was diffuse fusiform aneurysmal dilatation of the entire proximal, mid and distal Right Coronary Artery (RCA) with intervening areas of decreases calibre in proximal, mid and distal RCA. There was no evidence of any intraluminal clot. Left main coronary artery, posterior left ventricular branch and posterior descending artery were normal in course and calibre. The coronary ostia were normal in position.

Coronary artery aneurysm (CCA) is a focal dilatation of a coronary artery whereas ectasia is diffuse dilatation of the vessel [1]. In children, according to the criteria established by the Japanese Ministry of Health in 1984, a CCA is present when the diameter of the lumen is more than 3 mm in children younger than 5 years of age or more than 4 mm in those 5 years of age or older [2]. According to the American Heart Association statement, aneurysms may be classified as small (<5mm internal diameter), medium (5–8mm internal diameter), or giant (>8mm internal diameter) [2, 3].

The common causes of CCA include atherosclerosis, inflammatory disorders, congenital anomalies, infections, trauma and iatrogenic injury; Kawasaki disease (KD) being the most common cause of childhood CCA. They can be asymptomatic or present with angina, myocardial infarction, congestive heart failure or sudden death [4, 5]. 17 % of CCA are congenital and are usually associated with fistulous communication.

KD (mucocutaneous lymph node syndrome) is a multisystemic panarteritis with predilection for coronary vessels. Patients are usually <5 years old and present with fever, generalised malaise, conjuctival injection, strawberry tongue, rash, erythema of palms and soles, cervical lymphadenopathy and cardiac complications [6]. Cardiac complications include pericardial effusion, myocarditis, valvular regurgitation, coronary artery aneurysms/ectasias, premature atherosclerosis, thrombosis, embolic phenomenon, fistulisation and myocardial infarction. CCA develop in about 15-25 % of untreated children with KD in acute phase of illness [7]. However, with advent of gamma globulin therapy, the incidence has decreased to 5% [8]. CCA in KD usually involves the proximal part of vessels [9]. They can remain stable, regress or enlarge with time, though half of the patients show spontaneous regression within 2 years of onset of disease [10]. Once large aneurysms develop, risk of major adverse cardiac events increase. Therefore early recognition and mitigation of disease progression is necessary.

Two-dimensional (2D) echocardiography is free of radiation and can be used a screening method to detect CCA; however, visualisation of the distal coronary arteries is often limited. CT angiography is a non-invasive method to diagnose and evaluate the number, distribution and extent of aneurysms, maximal diameter, presence of any intraluminal thrombi and any associated complications like myocardial infarction. It also plays an important role in follow-up of patients with CCA. MRI/ MR angiography can evaluate aneurysms as well as estimate myocardial perfusion. However, because of its limited availability, long scanning time and motion artefacts, it is not the investigation of choice.