Functional behavior and morphology of the coronary artery wall in patients with Kawasaki disease assessed by intravascular ultrasound

Objectives. To examine the development of coronary artery lesions in Kawasaki disease, we assessed the functional behavior and morphology of coronary arteries by intravascular ultrasound. Background. Long-term follow-up studies of patients with Kawasaki disease have demonstrated the development of localized coronary stenoses even after aneurysms have regressed. It is also possible that angiographically normal coronary segments in patients with this disease may retain histologic changes. Methods. Twenty-three patients followed up by serial coronary angiography were examined at a mean age ± SD of 14.9 ± 2.9 years. The thickness of the intima-media complex was measured by intravascular ultrasound (30 MHz; 3.5 or 4.3F; 1,800 rpm). Coronary reactivity to nitroglycerin was determined by measuring percent changes in cross-sectional coronary artery area after intracoronary injection (7 μg/kg body weight) of this agent. Results. A remarkably thickened intima-media complex was observed at the sites with persisting (0.54 ± 0.20 mm, n = 19) and regressed (0.84 ± 0.40 mm, n = 23) aneurysms. Mild thickening of the intima-media complex was often observed even in angiographically normal segments (0.22 ± 0.05 mm, n = 31), in the left main coronary artery (0.47 ± 0.15 mm, n = 20) and at normal branches (0.36 ± 0.09 mm, n = 13). Coronary reactivity to nitroglycerin was significantly lower at the sites of regressed aneurysms (12.8 ± 6.6%, n = 9) than in normal segments (32.8 ± 10.9%, n = 13, p < 0.01), indicating the presence of functional impairment at the sites with regressed aneurysms. Decreased nitroglycerin reactivity was also observed in some segments without evidence of aneurysm. Conclusions. These results indicate that in patients with Kawasaki disease the coronary disease accompanying impaired reactivity to nitroglycerin is present at the sites of regressed aneurysms as well as in angiographically normal coronary segments. We suggest that these sites with morphologic and functional abnormalities are related to the development of significant stenosis.