Fast and slow progressors of infarct growth in basilar artery occlusion strokes

Background Heterogeneity in the infarct growth rate among anterior circulation large vessel occlusion (LVO) strokes has triage and treatment implications. Such data are lacking for basilar artery occlusion (BAO) strokes. We aim to describe the variability in brainstem infarct volume at presentation and compute the distribution of the infarct growth rate (IGR) and rate of loss of neurons during BAO strokes. Methods A retrospective review of consecutive patients with BAO stroke with pretreatment MRI was performed. Ischemic core volume was manually calculated (product of slice thickness and sum of area of region of interests) for the brainstem lesion. The distribution of various brainstem infarct volume groups was analyzed and the IGR (including rate of loss of neurons) was computed. Results Fifty-nine patients were included. Mean age was 64 +/- 13 and 34% were men. Mean National Institutes of Health Stroke Scale score was 20 +/- 11 and time to MRI was 9 +/- 5 hours. Mean brainstem ischemic core volume was 4.5 +/- 4.6 mL. According to predefined thresholds, 13% and 6% of patients with BAO stroke in the 0-6 hour time window were fast (5-10 mL) and ultra-fast progressors (>10 mL), respectively, and 14% of patients in the 6-24 hour time window were slow progressors (<1 mL). Median and mean rate of loss of neurons was 146 300 neurons/min and 261 300 (+/- 400 000) neurons/min, respectively, and ranged from 2.12 million. Conclusion Approximately 14% of BAO strokes are slow progressors and 19% are fast/ultra-fast progressors, with the rate of loss of neurons ranging from 2.1 million/min. Large heterogeneity exists in brainstem infarct volume at presentation and IGR among patients with BAO stroke.