Flicker‐induced retinal vascular dilation in ipsi‐ and contralateral eyes of patients with carotid stenosis before and after carotid endarterectomy: a prospective study

Purpose Retinal vascular function was assessed in patients with carotid stenosis (CS) before and six months after carotid endarterectomy (CEA) and in controls at a six‐month interval. Methods We studied 68 patients (81% male, mean age 69) and 41 healthy non‐medicated controls (77%, 68) from March 2015 to December 2018. Our ophthalmological examination included flicker‐induced arteriolar and venular measurements with a Dynamic Vessel Analyser in both eyes. Results At baseline, flicker‐induced arteriolar and venular dilation was reduced in the ipsilateral eyes of the patients compared with dilation in the controls (arteriolar 1.0% versus 2.6%, p = 0.001 and venular 2.2% versus 2.8%, p = 0.049). These differences subsided after CEA. In patients' ipsilateral eyes, flicker‐induced arteriolar dilation was borderline postoperatively (preoperative 1.0% versus postoperative 1.6%, p = 0.06), whereas venular dilation increased (2.2% versus 2.8%, p = 0.025). We found various tentative associations with the change in flicker‐induced dilations after CEA, but not with the preoperative dilations. Conclusions Postoperative recovery of the reduced flicker‐induced arteriolar and venular dilatation in the ipsilateral eye shows that, after CEA, the activity‐dependent vascular reactivity of haemodynamically compromised retinal tissue can improve.