Correlation between Optical Coherence Tomograph 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)

Abstract

Objective To determine whether Optical Coherence Tomography Angiography (OCTA) findings of retinal and Optic Nerve Head (ONH) can help predict functional outcomes (mRS, modified Rankin Score) in patients with Extracranial Carotid Artery Atherosclerotic Disease (ECAD).Background OCTA can image retinal vasculature without the need of contrast injection. Previous studies have evaluated OCTA findings in the pre and post carotid revascularization procedures, however, none have evaluated the utility of OCTA in predicting the clinical outcome in ECAD associated stroke, which we aim to explore in this study.MethodsFor this prospective exploratory study, OCTA findings in patients with ischemic stroke due to ECAD at 3-6 weeks of stroke onset were observed for mRS at three months. OCTA was also performed on risk factors matched controls who did not have carotid artery stenosis and the findings were compared with those of cases. Results Twenty-three patients of ECAD stroke (cases arm) and twenty-three risk factor matched controls were enrolled. Mean age was 53.14± 12.28 years and majority were males. There was a significant difference between cases and controls in the Deep Vessel Density (DVD) at macula (p = 0.0007) and in the Radial Peripapillary Capillary Perfusion Density (RPCPD) at the Optic Nerve Head (ONH) (p = 0.0007). Statistically significant difference was noted in the total superficial vessel density at macula (normal vs abnormal Superficial Vessel Density) in the ipsilateral eye and clinical outcome at 3 months (very good vs poor outcome, mRS 0-1 vs mRS 2-6, respectively ( p= 0.0361). There was statistically insignificant correlation between the RPCPD at the ONH and National Institutes of Health Stroke Scale (NIHSS) at the time of 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).Conclusion OCTA findings (total superficial vessel density at macula) at three to six weeks of stroke onset may predict functional outcome at three months in patients with acute ischemic stroke. Further studies involving larger patient cohorts, may help establish OCTA as a new biomarker for predicting and monitoring clinical and functional outcomes in patients with Extracranial Carotid Artery Atherosclerotic Disease, in a fast, non-invasive and reproducible manner.