Risk of recurrent childhood arterial ischemic stroke in a population-based cohort: the importance of cerebrovascular imaging.

OBJECTIVE: Few data exist regarding rates and predictors of recurrence after childhood arterial ischemic stroke. We sought to establish such rates within a large, multiethnic population and determine whether clinical vascular imaging predicts recurrence. PATIENTS AND METHODS: In a population-based cohort study, we collected data on all documented cases of arterial ischemic stroke among 2.3 million children (<20 years old) enrolled in a northern Californian managed care plan from January 1993 to December 2004. Perinatal strokes were those that occurred by 28 days of life. Data on cerebrovascular imaging (conventional or magnetic resonance angiography), including presence of vascular abnormalities, were abstracted from official radiology reports. We used Kaplan-Meier survival-analysis techniques to determine rates and predictors of recurrent stroke.
RESULTS: Among 181 incident childhood stroke cases (84 perinatal; 97 later childhood), there were 16 recurrent strokes (1 after a perinatal stroke) at a median of 2.7 months. The 5-year cumulative recurrence rates were 1.2% after perinatal stroke and 19% after later childhood stroke. Of the 97 children with later childhood strokes, 52 received cerebrovascular imaging, predominantly magnetic resonance angiography (n = 36) and conventional angiography (n = 26). Although there were no recurrences among children with normal vascular imaging, children with a vascular abnormality had a 5-year cumulative recurrence rate of 66%.
CONCLUSIONS: Strokes recur in one fifth of cases of later childhood arterial ischemic stroke but are rare after perinatal stroke. Among the later childhood cases, cerebrovascular imaging identifies those at highest risk for recurrence.