Abstract 159: Impact of Laterality on Inpatient Outcomes and Complications of Middle Cerebral Artery Acute Ischemic Stroke: A Retrospective Cross‐Sectional Study

Background and Objectives Acute ischemic stroke (AIS) affecting the middle cerebral artery (MCA) remains a major global cause of death and disability. However, it remains unclear whether the laterality of MCA strokes independently influences inpatient outcomes. Despite the fact that the NIHSS is heavily weighted towards left‐sided AIS, we hypothesize that right MCA strokes (R‐MCAS) are associated with worse inpatient outcomes since they would require more severe deficits to amount to a comparable NIHSS for a left MCA stroke. Methods A retrospective cross‐sectional analysis was conducted using data from the NIS between 2015 and 2022. This nationally representative sample included adult patients (≥18 years old) in the United States hospitalized primarily for MCA strokes and with reported NIHSS scores. Patients were stratified into R‐MCAS and L‐MCAS. Outcomes included odds of inpatient mortality, routine discharge, complications, comorbidities, and receipt of reperfusion therapy. Propensity score‐based inverse probability of treatment weighting (IPTW) adjusted for confounding factors. Multivariable logistic regression evaluated adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for all outcomes. Results Among 489,360 AIS hospitalizations, 263,495 (53.8%) were L‐MCAS and 225,865 (46.2%) were R‐MCAS. Following IPTW, R‐MCAS had significantly higher odds of inpatient mortality (aOR: 1.19; 95% CI1.12‐1.26,p<0.001) and lower odds of routine discharge (0.7860.760‐0‐.812,p<0.001). R‐MCAS were significantly more likely to receive endovascular thrombectomy (1.26 1.22‐1.30, p<0.001) and less likely to receive intravascular thrombolysis (0.9650.937‐0.994,p=0.018). R‐MCAS was significantly associated with increased odds of cerebral edema/herniation (1.531.47‐1.59,p<0.001), hemorrhagic transformation (1.251.20‐1.30,p<0.001), and sepsis (1.351.25‐1.46,p<0.001). L‐MCAS was associated with a higher likelihood of coma (0.920 0.889‐0.952,p<0.001). Conclusion There was no difference in age and gender between patients with left and right MCA strokes. R‐MCAS were associated with lower NIHSS scores and longer length of stay. They were also more likely to get endovascular thrombectomy and less likely to get intravascular thrombolysis. Patients with right‐sided MCA strokes were associated with worse discharge disposition, with increased likelihood of inpatient mortality. NIHSS bias toward assessment and valuation of patients’ language abilities may place R‐MCAS patients at increased risk of adverse post‐stroke outcomes and complications. Recognition of the subtle signs of non‐dominant hemisphere strokes may lead to more rapid detection, effective treatment, and improved outcomes.