1259. Variability in Clinical Characteristics and Outcomes Following Large Territory Ischemic Stroke

Authors: Benjamin Yim, MD; Benjamin Yim, MD; William Mack, MD; Brian Walcott, MD (La Crescenta, CA)

Introduction: Randomized controlled trials have demonstrated the benefit of early decompressive surgery for properly selected patients suffering from large territory ischemic infarction. However, not all patients with large territory ischemic stroke develop significant brain swelling. We aim to describe the variability in brain edema formation following large territory ischemia. Methods: A retrospective review (Oct 2015 – Oct 2017) of a university hospital stroke registry was performed. 53 patients were identified from the following inclusion criteria: age 18-80 years old, anterior circulation hemispheric infarct less than 24 hours from last known well time, and radiographic confirmation of a lesion volume greater than 60 cc or 1/3 the middle cerebral artery territory. Main exclusion criteria included patients with large hemorrhagic transformation or lack of subsequent follow up imaging. Stroke volume was estimated using the ellipsoid method (ABC/2) or automated from the RAPID software (iSchemaView). Cerebral edema assessed by measurement of midline shift on computerized tomography. Results: The correlation between stroke volume and midline shift (surrogate for edema) was moderate, r=0.51.   However, there were many patients with large territory stroke with little/no brain edema (<5mm midline shift, n=35, 66%). Age was not a statistically associated variable for developing significant cerebral edema (p =0.9). Poor outcome at discharge (mRS >3) was similar for groups with either <5mm or ≥5mm of midline shift (p=0.65) Conclusion: Large volume ischemic stroke is generally associated with increasing amount of cerebral edema. Significant variability in outcomes exists among this patient population, with the majority in this series developing little/no brain edema. Further study of clinical and genetic characteristics may aid in identifying those patients most likely to develop severe edema and benefit from surgery, while avoiding harm in the others.