Background—Coronary abnormalities after Kawasaki disease (KD) may be associated with endothelial dysfunction due to intimal hypertrophy. The purpose of this study was to evaluate myocardial flow reserve (MFR) and endothelial function in regressed aneurysmal regions after KD.

Methods and Results—Subjects were 12 patients aged 16.0±2.6 years who suffered from KD at 1.7±1.5 years and 12 normal subjects aged 26.5±3.4 years. MFR and endothelial function were estimated, respectively, by changes in myocardial blood flow (MBF) during ATP infusion and by that during cold pressor test using ¹⁵O-water positron emission tomography. Data from 24 regressed aneurysmal regions were compared with those from the corresponding regions (n=36) in the control group. Although the MBF at rest in the regressed aneurysmal regions was similar to that in controls, the MBF at a hyperemic state induced by ATP infusion in the regressed aneurysmal regions was significantly lower than that in the control regions. Therefore, the MFR in regressed aneurysmal regions was significantly lower than that in controls (3.53±0.95 versus 4.60±1.14; P<0.05). MBF at rest and during the cold pressor test did not change in the control regions, but it was significantly reduced in regressed aneurysmal regions. The ratio of MBF during the cold pressor test to MBF at rest was significantly lower in regressed aneurysmal regions than in control regions (0.67±0.15 versus 1.00±0.15; P<0.05).

Conclusions—MFR and endothelial function are often impaired in regressed aneurysmal regions after KD, and tomography enables the noninvasive evaluation of coronary function.