Imaging of retinal vasculature among patients being assessed for carotid occlusive disease

Cardiovascular disease causes damage to large blood vessels that may result in narrowing and occlusion of major arteries. Because the retina obtains blood flow from the carotid arteries, occlusion of the carotid arteries may lead to retinal microvascular remodeling and changes. Our central premise is that patients with carotid occlusive disease have microvascular changes to their retinal vasculature, which may be used as a potential biomarker for macrovascular disease onset and progression. A previous study of 50 patients found retinal changes on optical coherence tomography angiography (OCTA) among patients with carotid artery stenosis; however, this study was limited to the macula and optic nerve by the small size of the OCTA field of view.1 We hypothesize there are similar changes to the retinochoroidal microvasculature on the peripheral retina that are not appreciated on standard OCTA. We will test this hypothesis using swept source optical coherence tomography angiography (SS OCTA), an imaging modality that is able to visualize a larger area of the retina and identify peripheral retinochoroidal changes among patients with carotid occlusive disease. There is currently no clear research to guide the decision for further carotid occlusion evaluation among patients with changes to retinal perfusion. Carotid artery occlusion is an important risk factor for ischemic stroke and transient ischemic events without prior symptoms, and medical and surgical management can reduce the likelihood of these events. As such, early identification of patients with carotid occlusive disease is important for the prevention of major cerebrovascular events. We hypothesize that microvascular changes on SS OCTA (retinal vessel density, caliber, tortuosity, and perfusion) may predict macrovascular changes in degree of carotid artery stenosis. We will test this hypothesis by correlating retinochoroidal changes with degree of carotid occlusion. We expect that SS OCTA biomarkers may have the potential to improve early detection of carotid occlusion.