Abstract 84: Late (5-20 Years) Outcome After STA-MCA Anastomosis and Ultimate Indirect Bypass in Patients With Moyamoya Disease

Abstract

Background and Purpose: Surgical revascularization is now known to improve the outcome in patients with moyamoya disease. However, majority of previous studies reported their short-term (<5 years) outcome. Therefore, this study was aimed to evaluate long-term (5 to 20 years) outcome after STA-MCA anastomosis and ultimate indirect bypass, encephalo-duro-myo- arterio-pericranial synangiosis (EDMAPS). Methods: Cumulative incidence of late morbidity/mortality and disease progression were evaluated among 93 patients who underwent STA-MCA anastomosis and EDMAPS. All of them were prospectively followed up for longer than 5 years post-surgery (mean, 10.5±4.4 years). There were 35 pediatric and 58 adult patients. Clinical diagnosis included TIA or ischemic stroke in 80 patients, hemorrhagic stroke in 10, and asymptomatic in 3. STA-MCA anastomosis and EDMAPS were performed onto their 141 hemispheres. MRI and MRA were performed every 6 or 12 years during follow-up periods. Results: During follow-up periods, 92/93 patients were free from any stroke or death, but one recurred hemorrhagic stroke (0.10% per patient-year). Disease progression occurred in the territory of the contralateral carotid or posterior cerebral artery (PCA) in 19 hemispheres of 15 patients (1.5% per patient-year). The interval between initial surgery and disease progression varied from 0.5 to 15 years. Repeat bypass surgery for anterior and posterior circulations resolved ischemic attacks in all 10 patients. Conclusion: STA-MCA anastomosis and EDMAPS would be the best choice to prevent further cerebrovascular events for longer than 10 years by widely providing surgical collaterals to both the MCA and ACA territories. However, regular follow-up would be essential for longer than 10 years post-surgery to identify the disease progression in the territory of contralateral carotid artery and PCA and prevent late cerebrovascular events.