[Long-term Outcome over Five Years after Surgical Revascularization in Adult Moyamoya Disease].

BACKGROUND AND PURPOSE: The long-term outcome of patients with adult moyamoya disease following revascularization surgery remains unclear. Here, we investigated these outcomes more than five years after revascularization surgery.

PATIENTS AND METHODS: This study included 48 cerebral hemispheres from 26 patients who underwent revascularization surgery for adult moyamoya disease. The mean follow-up duration was 14.3(5.5-25.6)years. The risk factors of late-onset hemorrhage after revascularization surgery were compared between the bleeding and non-bleeding groups. We also estimated cumulative bleeding-free survival rates using Kaplan-Meier curves.

RESULTS: Four patients experienced late-onset bleeding during the follow-up period. Bleeding occurred after an average of 11(8.5-16.4)years following revascularization surgery. The annual hemorrhagic rate was 1.14%. In the bleeding group, higher Suzuki stage(p=0.02), posterior cerebral artery(PCA)involvement(p<0.01), cerebral aneurysm(p=0.04), microbleeds(p=0.03), and post-operative periventricular anastomosis, especially in the thalamus and the choroidal artery(p<0.01 and p=0.01 respectively), were significantly different from those in the non-bleeding group. Kaplan-Meier analysis showed that the probability of late-onset bleeding was higher with postoperative periventricular anastomosis(p<0.01 for thalamic type, p=0.01 for choroidal type), higher Suzuki stage(p<0.01), PCA involvement(p<0.01), and cerebral aneurysm(p=0.02).

CONCLUSIONS: In spite of good perfusion and reduction in moyamoya vessels after revascularization surgery, the risk of bleeding persisted. Periventricular anastomosis, especially in the thalamus and choroidal artery, after surgery, higher Suzuki stage, presence of obstructive lesions in the PCA, and cerebral aneurysm may be associated with late-onset bleeding after surgery. More studies are needed to identify the risk factors for late-onset bleeding after revascularization surgery for moyamoya disease.