Correlation between Optical Coherence Tomography Angiography (OCT- A) findings at three to six weeks and functional outcome (modified Rankin Scale – mRS) at three months of onset of acute ischemic stroke due to Extracranial Carotid Artery Atherosclerotic Disease (ECAD)

Background and Aims: Optical Coherence Tomography Angiography (OCTA) images retinal vasculature without the need of contrast injection. In the present study we aim to determine whether OCTA findings can predict functional outcomes (mRS, modified Rankin Score) in patients with ECAD -stroke. Material: and Methods This Exploratory study enrolled was performed on adults with acute ischemic stroke due to ECAD at 3-6 weeks of stroke onset and risk factors matched controls without carotid artery stenosis. Results: : Twenty-three ECAD stroke patients (cases) and twenty-three risk factor matched controls were enrolled. There was a significant difference between cases and controls in the Deep Vessel Density (DVD) at macula (p = 0.0007). Statistically significant difference was noted in the total superficial vessel density (SVD) at macula [SVD within 1 standard deviation (SD) of control data vs SVD beyond 1 SD of control data) in the ipsilateral eye and functional outcome at 3 months (Poor vs very good outcome, mRS 0-1 vs mRS 2-6, respectively ( p= 0.0361). There was statistically insignificant correlation between the RPCPD at ONH and National Institutes of Health Stroke Scale (NIHSS) at admission, mRS at discharge, and functional outcome (mRS) at 3 months of stroke onset (r =0.33, r=0.35, r=0.39; p=0.11, p=0.09, p=0.06, respectively). Conclusions: : The findings of this exploratory study led us to hypothesize that OCTA findings may predict three-month outcomes in cases of ECAD associated stroke and this could be useful in decision making in intervention studies as to whether intervene or not in patients having critical or non-critical ECAD for preventing future stroke.