Abstract TP257: Comparison of Etiology of Central Retinal Artery Occlusions versus Branch Retinal Artery Occlusions

Introduction: Retinal artery occlusions (RAO) are a cerebral stroke equivalent and an ophthalmologic emergency that results in significant vision impairment. Etiology of branch retinal artery occlusions (BRAO) and central retinal artery occlusions (CRAO) varies widely in the literature, much of which comes from outside the United States. Furthermore, there is limited data comparing the etiologies of BRAO to CRAO. The Objective of this study is to compare BRAO to CRAO to determine if there is a difference in the etiology. Having a neuroscience hospital affiliated with a specialty ophthalmologic ER affords us a unique opportunity to conduct this research. Methods: Retrospective study looking at one year of data (April 2017 to April 2018), of patients admitted from our ophthalmologic ER to our acute stroke service with a diagnosis of RAO. A total of 86 patients met these criteria, 35 BRAO, and 51 CRAO. Etiology at discharge was recorded for each patient and the two groups were compared using odds ratio and Fisher's exact test. Results: Many of the patients were discharged without a clear etiology, 16 (45.7%) in the BRAO group and 26 (51.0%) in the CRAO group. Carotid/thromboembolic source was determined to be the etiology in six (17.1%) BRAO and four (7.8%) CRAO. Small vessel disease was responsible for 10 (28.6%) BRAO and 13 (25.5%) CRAO. "Other” etiology was found in three (8.6%) patients in the BRAO group, and one (2%) patient in the CRAO group. None of these etiologies had a statistically significant difference between the two groups. However, none of the patients with BRAO were found to have a cardioembolic etiology, as opposed to seven (13.7%) of the CRAO patients. This finding was statistically significant (odds ratio 0.084, P-value 0.038). Conclusions: In conclusion, the results of this study demonstrate that while there is much overlap in the etiology of BRAO and CRAO, and often the etiology remains cryptogenic, CRAO are statistically more likely to have a cardioembolic etiology than BRAO.