A long-term study of posterior circulation changes after revascularization in patients with moyamoya disease

OBJECTIVE This study aimed to explore the long-term course of posterior circulation changes and predictors in paMETHODS The authors retrospectively enrolled patients who were diagnosed with MMD and underwent encephaloduroarteriosynangiosis (EDAS) surgery at the authors' department from December 2002 to September 2011. A comparative study between short-term (6-12 months) and long-term (>= 9 years) follow-up angiography was conducted. The progression of lesions was defined from lower to higher stages of the posterior cerebral artery (PCA). RESULTS Eighty-eight patients who received indirect EDAS were enrolled in the study. The mean age at first surgery was 28.1 +/- 15.0 years. Among these 88 patients with MMD, 39 (44.3%) exhibited transient ischemic attack and 27 (30.7%) exhibited infarction, comprising 5 with occipital lobe infarction, 14 (15.9%) with hemorrhagic symptoms, and 8 (9.1%) with atypical symptoms as the initial symptoms. Heterozygous mutations occurred significantly more frequently in the cases that presented with PCA involvement. During follow-up, stage progression of PCA was observed in 21 patients (28 hemispheres). At short-term follow-up, 21/176 (11.9%) hemispheres had progression of steno-occlusive lesions in the PCA. At long-term follow-up, 7 (4.0%) hemispheres had progression of steno-occlusive lesions in the PCA. At shortterm follow-up, the progression of steno-occlusive lesions in the PCA was associated with progression of the internal carotid artery. Stage progression of PCA occurred significantly more frequently in the cases with PCA involvement on preoperative angiography. Nine strokes (10.2%) occurred in 88 patients during long-term follow-up. Four patients (4.5%) presented with ischemic stroke, including 2 with occipital lobe infarctions. CONCLUSIONS Progression of PCA stenosis is common in patients with MMD, even if the PCA is normal initially. Mutations of RNF213 p.R4810K may predict PCA involvement or progression. Follow-up of the PCA in MMD patients should be conducted, and timely surgical revascularization is needed.