Assessment of the Ability of Intravenous Myocardial Contrast Echocardiography to Identify Perfusion Abnormalities in Patients with Kawasaki Disease

Abstract

Patients (pts) with Kawasaki disease (KD) who develop myocardial infarction are usually asymptomatic before the event; thus, it is crucial that pts at risk be identified. The aim of our study was to assess the ability of myocardial contrast echocardiography (MCE) with harmonic power Doppler imaging (HPDI) to identify perfusion abnormalities in patients with KD at rest and during pharmacological stress imaging with dipyridamole. Results were compared with those of 99mTc-tetrofosmin single-photon emission computed tomography (SPECT) imaging as the clinical reference standard. MCE with HPDI was performed on 20 pts with a history of KD. Images were obtained at baseline and during dipyridamole infusion (0.56mg kg-1) in the apical two- and four-chamber views. Myocardial opacification suitable for the analysis was obtained in all pts (100%). Nine pts with stenotic lesions had a reversible defect after dipyridamole infusion detected by both MCE with HPDI and SPECT, and 3 pts with a history of myocardial infarction had a partially or completely irreversible defect detected by both 2 methods. Three pts. with coronary aneurysm without stenotic lesion, 4 pts with regressed coronary aneurysm, and 2 pts with normal coronary artery in acute phase also had normal perfusion at rest and after pharmacological stress by the 2 methods. A 96% concordance (kappa = 0.87) was obtained when comparing the respective segmental perfusion scores using the two methods at baseline, and an 86% concordance (kappa = 0.81) was obtained at postdipyridamole infusion. After combining baseline and postdipyridamole images, each segment was labeled as having either normal perfusion, irreversible defects, or reversible defects. Using these classifications, concordance for the two methods was 92% (kappa = 0.87). MCE with HPDI is a safe and feasible method by which to detect asymptomatic ischemia due to severe stenotic lesion as a complication of KD.