Exercise myocardial perfusion imaging to evaluate inducible ischaemia in children with Kawasaki disease.
Kawasaki disease (KD) is an acute multi-system vasculitis of unknown aetiology, which occurs predominantly in infants and young children. Coronary artery abnormalities may occur in 15-25% of patients who are not treated in the acute phase of the disease with a high dose of intravenous immunoglobulin. Myocardial perfusion imaging is used as a modality to monitor the cardiovascular effects of the disease. The objective of our study was to assess the feasibility and results of exercise myocardial perfusion scintigraphy in children with Kawasaki disease. We performed stress myocardial perfusion imaging in 84 patients suffering from KD. The diagnosis of KD was based on the criteria laid down by the American Heart Association. Myocardial perfusion imaging was performed using either thallium or technetium-99m tetrofosmin. Physical exercise using the Bruce protocol was the most frequent cardiac stressor (74 patients) whereas in few patients (seven patients) dobutamine was used to increase the heart rate. Stress-induced reversible perfusion defects were found only in 12 of the total number of patients. Among these two had coronary artery abnormalities on echocardiography. Four of these patients had achieved adequate heart rate with stress. Two among these patients had a repeat imaging done after 1 year and the perfusion defects showed complete resolution in them. This study thus suggests that reversible perfusion defects are seen in asymptomatic patients with KD and that the presence of perfusion defects may not be associated with echocardiographic demonstration of coronary abnormalities. The treadmill test is a reasonable stress protocol for these patients.