Objective: The prevention of rebleeding is one of the most important issues in the successful treatment of moyamoya disease with hemorrhagic onset. However, the natural course of hemorrhagic moyamoya disease and the characteristics of rebleeding remain unclear.
Methods: To study the natural course of the disease in conservatively treated patients, we analyzed long-term follow-up reports on 36 patients (12 male and 24 female) treated without bypass surgery at our hospitals before 1994 (mean follow-up, 12.7 +/- 7.1 yr; range, 2.9-27.0 yr).
Results: Of our 36 patients, 22 (61.1%) experienced rebleeding; there were 29 rebleeding episodes. The outcomes in patients with rebleeding were worse than in patients who did not rebleed (P < 0.05); in most cases, unsatisfactory results were attributable to rebleeding. Kaplan-Meier and multivariate analysis of rebleeding-free survival showed that age at onset (>36 yr) was a statistically significant risk factor; sex, hypertension, type of intracranial bleeding, and outcome after the first bleeding episode were not. Although the intervals between the first and subsequent episodes varied, both the rebleeding rate and the number of rebleeding episodes were highest in patients 46 to 55 years old.
Conclusion: Rebleeding is the most important factor in unsatisfactory outcomes of patients with hemorrhagic moyamoya disease. Rebleeding seems to be age-related; rebleeding occurs at an increased rate when patients reach the age range of 46 to 55 years. Patients with hemorrhagic moyamoya must be followed up throughout their lives, even if their neurological status is excellent.