Abstract WP38: High Variability in Neuronal Loss: Time is Brain, Re-quantified

Abstract

Background and Purpose: Rapid and progressive loss of brain elements occurs in the setting of acute ischemic stroke (AIS) due to a large-vessel occlusion (LVO). With time, the amount of brain lost increases. This has been previously quantified to be approximately 1.9 million neurons per minute. Clinically observed phenotypes indicate that large heterogeneity exists in ischemic cell death, in this study we aim to quantify the distribution and range of rate of loss of brain elements. Methods: After Institutional Review Board approval, we performed a retrospective chart review of consecutive anterior circulation AIS due to LVO. Ischemic core volume was measured using automated software processing and time from last known well to imaging was recorded. Using previously published data on brain volume and element counts from morphometry and neuro-stereology studies, we computed rate of loss of brain elements for our real-world LVO stroke patients. Results: Mean ischemic core was 50.4 ml and mean time to imaging from symptoms onset was 8.7 hours. This translated to a mean loss per minute of 2.03 million neurons, 14.8 billion synapses and 12.8 kilometers myelinated fibers. The rate of neuron loss was highly variable, ranging from less than 35,000 to more than 27 million neurons per minute. Conclusions: AIS due to LVO has wide ranging phenotypes of infarct growth. Rate of neuron loss per minute ranges from less than 35,000 to more than 27 million, with a mean and median of 2 million and 0.9 million respectively. These data suggest that time to treatment may be even more critical for a subset of patients while a separate population of patients may continue to benefit from reperfusion therapy, even at late time windows.