Retinal vessel dynamic functionality in the eyes of asymptomatic patients with significant internal carotid artery stenosis.

Background: The goal of this study was to assess the retinal microvascular function in asymptomatic patients with hemodynamically significant internal carotid artery stenosis (ICAS) and to assess the potential efficacy of carotid endarterectomy (CEA) for the improvement of vessel functionality.

Methods: Retinal vessel caliber and reactions to flicker stimulation were assessed in both eyes of 65 asymptomatic patients with unilateral hemodynamically significant ICAS and 34 healthy subjects. Subsequently, the recruited ICAS patients were referred for standard unilateral CEA procedure. The full ophthalmologic examination of both eyes and vessel analysis were performed 1 day before and 3 months after CEA.

Results: The venous responses to flicker stimulation were significantly lower in the EIS (eyes ipsilateral to stenosis) and ECS (eyes contralateral to stenosis) compared with those in the controls (P<0.0001 and P<0.0001, respectively). No changes were identified in retinal vascular flicker responses after CEA in both groups of eyes compared with the baseline values. We observed a decrease in CRVE (central retinal venular equivalent) after the CEA both in eyes ipsilateral (P=0.01) and contralateral (P=0.04) to CEA. Likewise, a decrease in CRAE (central retinal arteriolar equivalent) was identified in the eyes ipsilateral to CEA (P<0.001).

Conclusions: This outcome strongly indicates that microvascular dysfunction is long-lasting despite the recovery of the flow in the carotid artery.