Can ultrasonographic measurement of optic nerve sheath diameter indicate large vessel occlusion in moderate and severe stroke patients?

Background: The aim of this study is to evaluate the effectiveness of optic nerve sheath diameter (OSND) measured by ultrasonography in predicting large vessel occlusion in patients with moderate and severe ischemic stroke. Materials and Methods: This single-center, prospective and observational study was conducted on patients and healthy volunteers who presented to Samsun University Samsun Training and Research Hospital Emergency Service with stroke symptoms within the first 24 hours of symptom onset between March 2023 and June 2023. Patients with known eye pathology, a history of increased intracranial pressure, and a National Institutes of Health Stroke Scale score (NIHSS) ≤5 were excluded from the study. Right and left ONSDs of the patients at the time of admission were performed by a single experienced emergency medicine assistant who had received basic ultrasonography training and had made a sufficient number of ultrasonographic ONSD measurements. In addition, patients' sociodemographic characteristics, vital signs, admission symptoms, symptom duration, comorbid diseases, Glasgow Coma Scale (GCS), NIHSS scores, Alberta Stroke Program Early CT Score (ASPECTS), modified Rankin Scale (mRS) scores at 3 months and Treatment outcomes were recorded. All these parameters in ischemic stroke patients were compared between groups with and without large vessel occlusion. Results: 151 stroke patients (patient group) and 63 healthy volunteers (control group) were included in the study. Of the stroke patients, 133 (88.1%) had ischemic stroke and 18 (11.9%) had hemorrhagic stroke. While the average age of the patient group was 70.44±12.83 years, the average age of the control group was 67.68±16.11 years. While 45.7% (n=69) of the patient group were women, this rate was 46% (n=29) in the control group. The patient and control groups were similar in terms of age and gender (p = 0.964 and p = 0.186, respectively). 58.6% (n=78) of ischemic stroke patients had large vessel occlusion. Patients with and without large vessel occlusion were similar in terms of age, gender, comorbidities and vital signs at admission (p>0.05). While GCS and ASPECT scores were higher in patients with large vessel occlusion, NIHSS score was higher in patients without large vessel occlusion (p<0.001, p=0.006 and p<0.001; respectively). According to the mRS score at the end of the 3rd month, 41% (n=32) of the patients with large vessel occlusion had a good clinical outcome, while this rate was 81.8% (n=45) in those without large vessel occlusion (p<0.001). The measured median right ONSD value was 6.1 (4.5-7.3) mm in patients with large vessel occlusion, while it was 5.7 (4.4-6.9) mm in patients without large vessel occlusion (p=0.002). The measured median left ONSD value was 5.9 (4.7-7.6) mm in patients with large vessel occlusion, while it was 5.7 (4.7-6.7) mm in patients without large vessel occlusion (p=0.002). In our study, the right ONSD measurement value of 6 mm and above was a significant indicator for large vessel occlusion with 51.28% sensitivity and 78.18% specificity (AUC=0.653, 95% CI=0.566-0.733, p=0.001). Left ONSD measurement value of 5.5 mm and above was a significant indicator for large vessel occlusion with 83.33% sensitivity and 40% specificity (AUC=0.647, 95% CI=0.560-0.728, p=0.002). Conclusion: In moderate and severe stroke patients, elevated ONSD levels measured by bedside ultrasonography at the time of admission can be used as a predictive parameter for large vessel occlusion. Keywords: emergency department, optic nerve sheath diameter, acute stroke, ischemic stroke, hemorrhagic stroke, ultrasonography, increased intracranial pressure