Exercise myocardial perfusion stress testing in children with Kawasaki disease

AIM: Kawasaki disease is the commonest cause of acquired coronary artery disease in children. Although echocardiography and treadmill stress testing have been the traditional methods of assessing coronary artery abnormalities and detecting myocardial ischaemia, respectively, these are inadequate for assessing perfusion and performance. We studied the safety and utility of exercise myocardial perfusion stress testing in children with previous Kawasaki disease. METHODS: Eleven subjects (median age 12 years; seven male and four female adolescents) with a history of childhood Kawasaki disease underwent 99mTechnetium-Tetrofosmin myocardial perfusion scan using a modified protocol. All had New York Heart Association effort tolerance class 1 and were asymptomatic at time of testing. Eight of 11 subjects had been treated with intravenous immunoglobulin during the acute phase. Six of 11 subjects had transient coronary artery dilatation. One subject with persistently dilated coronary arteries suffered an acute myocardial infarction 6 months after onset of Kawasaki disease but recovered well. Results were compared with clinical and echocardiographic findings. RESULTS: All subjects were able to complete the exercise test. There were no side effects associated with radioisotope injection. Ten of 11 patients, including the one who suffered a myocardial infarction had normal tests. The single subject with an abnormal scan showed a minimal (2%) fixed defect in the left ventricular wall. CONCLUSION: Exercise myocardial perfusion stress is a safe and useful method for the assessment of myocardial perfusion in co-operative children with a history of Kawasaki disease and is a useful addition to conventional methods for coronary risk stratification in such patients.