Giant Coronary Aneurysm Formation After Sirolimus-Eluting Stent Implantation in Kawasaki Disease
A 12-year-old girl with Kawasaki disease was admitted for percutaneous coronary intervention to her 90% mid-right coronary artery (RCA) stenosis (Figure 1A). There was also a large coronary aneurysm (15.9×11.9 mm) at her left main coronary artery (Figure 1B). Intravascular ultrasound (IVUS) showed marked intimal thickening (Figure 1C). The lesion was predilated with a 3.0/15-mm Aqua T3 balloon (Cordis) at 6 atm, followed by deployment of a 3.0/18-mm Cypher stent (Cordis) at 16 atm and postdilatation with a 3.5/16-mm Extensor balloon (Medtronic) at 16 atm (Figure 2A). IVUS showed good stent apposition (Figure 2B). The patient was prescribed clopidogrel for 3 months and aspirin for life. She remained asymptomatic, and a follow-up coronary angiogram was done 1 year afterward. Formation of 2 large eccentric and saccular neoaneurysms was found at the segments just proximal and distal to the stent; the sizes were 10.1×9.8 mm and 6.5×5.6 mm, respectively. Along the stented segment, smaller aneurysmal dilatations were also seen (Figure 3A and 3B). IVUS confirmed the 2 large aneurysms with malapposition of the stent within the vessel (Figure 3C). No neointimal hyperplasia within the stent was seen. Because the patient was asymptomatic and her parents were reluctant to have her undergo additional invasive treatment, she was discharged and monitored conservatively.
The formation of coronary aneurysm after percutaneous coronary intervention is relatively common in patients with Kawasaki disease, and the incidence varies from 15% to 18%. The exact mechanism is not certain but is associated with high-pressure balloon inflation (12 atm or higher), and the incidence is lower with the use of stents. New aneurysm formation after implantation of sirolimus stents, although reported, is rare. It is not certain whether the neoaneurysm formation in this case is related to the intrinsic characteristic response of the Kawasaki coronary vessel toward angioplasty injury, to a patient-specific hypersensitivity toward rapamycin, or even to a Kawasaki-specific hypersensitivity toward rapamycin. Because the morbidity associated with coronary aneurysms is substantial, until further information is available, the implantation of sirolimus-eluting stents in treating coronary stenosis in patients with Kawasaki disease should be performed with caution.