Dipyridamole-induced ischemia in a child with jeopardized collaterals after Kawasaki syndrome

The case of a 4-year-old boy with dipyridamole-induced ischemia is herein reported. The patient developed typical Kawasaki syndrome at 2 years of age, accompanied by coronary aneurysms in the left coronary artery (LCA) and the right coronary artery (RCA). The LCA was totally occluded at segment 6 and a distal area of the left anterior descending artery (LAD) was supplied by collaterals from the conus branch and the posterior descending artery (PD). Thallium-201 (Tl-201) myocardial scintigraphy was performed with intravenous administration of dipyridamole (DIP). DIP was infused at a dosage of 0.6 mg/kg for 5 min. Three minutes after the injection, myocardial ischemia occurred. Although 4 mg/kg of aminophylline was administered, the symptoms lasted for 20 min. Electrocardiogram suggested that ischemic lesions were located in the anteroseptal and inferior wall. Collaterals from PD could be recognized as jeopardized vessels and these collaterals probably participated in the ischemic attack. DIP could have increased the coronary flow into the uninvolved proximal branches of RCA. Subsequently DIP reduced coronary flow in the distal region of the stenotic RCA. Although T1-201 myocardial scintigraphy with DIP is a useful technique to estimate viability of the ischemic myocardium, it should be performed prudently in patients with multivessel diseases, such as those with jeopardized collaterals secondary to Kawasaki syndrome.