Longitudinal retinal and choroidal microvascular changes in carotid artery stenosis: Comparative outcomes of surgical and medical management using optical coherence tomography angiography

Abstract

Background & Objective: Carotid artery stenosis (CAS) is a major cause of chronic cerebral hypoperfusion and ischemic stroke. Because retinal circulation originates from the internal carotid artery, optical coherence tomography angiography (OCTA) may serve as a non-invasive surrogate marker of cerebral microvascular compromise.

Methods: Forty-six patients with CAS (92 eyes) and 41 healthy controls (41 eyes) were enrolled. Ipsilateral stenotic eyes were classified as Group 1, contralateral fellow eyes as Group 2, and controls as Group 3. Stenotic eyes were further subdivided into surgically treated (Group 1A) and medically managed (Group 1B) subgroups. Layer-specific OCTA and structural OCT parameters were assessed at baseline and at 1, 3, and 6 months. The predefined primary outcome was deep capillary plexus (DCP) inner vessel and perfusion density.

Results: At baseline, stenotic eyes demonstrated significantly reduced vessel and perfusion density across retinal and choroidal layers compared with controls (all p < 0.05). During follow-up, surgically treated eyes showed significant recovery in DCP inner metrics, whereas medically managed eyes exhibited smaller and less consistent changes. Several secondary choroidal parameters also improved gradually after revascularization. By month 6, multiple vascular indices in Group 1A approached values observed in contralateral non-stenotic eyes. Structural measures (RNFL and GCC thickness) showed modest, delayed improvement predominantly in the surgical subgroup.

Conclusions: CAS is associated with diffuse retinal and choroidal microvascular impairment. OCTA- derived parameters, particularly deep capillary plexus metrics, may represent accessible biomarkers of downstream hemodynamic compromise and microvascular recovery following intervention.