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The majority of coronary artery aneurysms in young adults and children are caused by Kawasaki disease. A case of undiagnosed childhood Kawasaki disease presenting as silent myocardial infarction during adolescence, which was successfully treated with coronary artery bypass grafting, is described. The present case is followed by a review of the literature.
A 16-year-old male with a history of syncope, atypical chest pain and dyspnea on exertion was referred for further evaluation. His electrocardiogram showed Q wave and mild ST elevation in the precordial leads. The patient had New York Heart Association class II dyspnea for the previous two years. Later, it was revealed that at age five years, the patient had a history of high fever, lymphadenopathy and skin rash compatible with Kawasaki disease.
Echocardiography showed severe left ventricular systolic dysfunction, global hypokinesia and left ventricular apical aneurysm. Aneurysmatic proximal coronary arteries could be seen in the parasternal short-axis view. Coronary angiography confirmed aneurysmal left main bifurcation with extension to the proximal left anterior descending and circumflex arteries. The left anterior descending artery was totally occluded with bridging collaterals (Figure 1). A right coronary angiogram showed an aneurysm and proximal dissection of the right coronary artery (Figure 2). The left ventriculography revealed severe left ventricular systolic dysfunction and an apical aneurysm. His thallium scan showed viable myocardium in the anterior wall but scar tissue in the apex, inferoapical and inferolateral walls. The patient underwent successful coronary artery bypass surgery using a left internal mammary artery graft, with marked improvement in his symptoms.
The causes of myocardial infarction in young children and adolescents include Kawasaki disease, Takayasu’s arteritis, Marfan syndrome, systemic lupus erythematosus and Behçet’s disease (1). In the present case, the coronary aneurysm was most likely secondary to Kawasaki disease. At age five years, the patient had a history compatible with Kawasaki disease. Kawasaki disease is an acute, self-limited vasculitis affecting the proximal coronary arteries that occurs predominantly in young children (2,3). Peak incidence occurs in children younger than two years old. Boys are more often affected than girls. Asian children have the highest incidence of this disease (3). Major complications are cardiovascular in nature, including coronary artery dilation and aneurysm, myocarditis, pericardial effusion, myocardial infarction and valvulitis (3–5). Approximately 15% to 20% of untreated children may suffer from ischemic heart disease or experience sudden death (5–7).
Aneurysms are more common in the proximal coronary arteries. Myocardial infarction might result from thrombus formation in the aneurysm and occurs most often in the first year after the illness, with rare occurrence later in life. The mortality rate of Kawasaki disease-related myocardial infarction is 22% after the first infarction, 66% after the second and 87% after the third (6). Coronary artery bypass surgery was successfully performed based on the viability of the anterior wall in this patient, with marked improvement in his symptoms. A recently published article by Kitamura et al (8) reported a 25-year outcome of pediatric coronary bypass surgery for Kawasaki disease. They followed 114 children ranging in age from one year to 19 years for up to 25 years. They found an excellent long-term prognosis, with a 25-year survival rate of 95%. Cardiac event-free survival was 60% at 25 years. Percutaneous coronary intervention and reoperation were the most common events. In general, percutaneous coronary intervention is not an initial option in these patients due to a large coronary aneurysm in the majority of cases. Based on excellent long-term results, coronary artery bypass surgery remains the primary treatment option in symptomatic patients.
Childhood Kawasaki disease rarely presents in later age as myocardial infarction. Echocardiography can usually detect aneurysmatic coronary arteries. Surgical intervention is the primary treatment option for this condition, with an excellent long-term prognosis.