Noninvasive quantification of coronary endothelial function by SPECT imaging in children with a history of Kawasaki disease.

PURPOSE: The feasibility of coronary function estimation by single photon emission computed tomography (SPECT) has been recently demonstrated. The aim of this study was to apply SPECT imaging in patients with previous Kawasaki disease (KD) to assess the coronary functional status at long-term follow-up of the acute phase of the disease. METHODS: Sixteen children with a history of KD underwent 99mTc-sestamibi imaging at rest and during the cold pressor test (CPT). Myocardial blood flow (MBF) was estimated by measuring first transit counts in the pulmonary artery and myocardial counts from SPECT images. Coronary endothelial function was expressed as the ratio of the CPT to rest MBF. RESULTS: Six KD patients without coronary artery lesions served as controls and ten with coronary artery aneurysms during the acute phase of the disease were separated into two groups: group 1 (n=4) with regressed and group 2 (n=6) with persistent aneurysm at follow-up. The estimated coronary endothelial function was higher in controls compared to patients with coronary artery aneurysms (2.5±0.3 vs 1.7±0.7, p<0.05). A significant difference in coronary endothelial function among groups was found (F=5.21, p<0.02). Coronary endothelial function was higher in patients of group 1 than in those of group 2 (1.9±0.6 vs 1.4±0.7, p<0.02). CONCLUSION: SPECT may be applied as a noninvasive method for assessing coronary vascular function in children with a history of KD, demonstrating an impaired response to the CPT, an endothelial-dependent vasodilator stimulus. These findings reinforce the concept that coronary endothelial dysfunction may represent a long-term sequela of KD.