Retinal embolization during carotid angioplasty and stenting: periprocedural data and follow-up

The purpose of this study was to prospectively evaluate the incidence of retinal emboli during carotid angioplasty and stenting (CAS) and to correlate emboli with clinical findings and transcranial Doppler (TCD)-detected cerebral embolic load. Between 2001 and 2005, 33 CAS procedures in 32 patients (23 [72%] male, 19 [58%] symptomatic, mean age 72.5 years [range 54.6 to 83.9]) scheduled for CAS were included in this study. Bilateral fundoscopy with retinal photography was performed by an experienced ophthalmologist immediately before, immediately after (fundoscopy only), and 1 day after the procedure and again at long-term follow-up (mean 37 months). Visual field testing was performed before CAS and again at long-term follow-up. TCD-detected cerebral emboli were stratified to five procedural phases: wiring, predilatation, stent placement, postdilatation, and cerebral protection device (CPD) use (if applicable). To establish correlation between TCD data and retinal embolization, Mann-Whitney test was used, and P < 0.05 was considered statistically significant. All procedures were performed successfully. In five of 33 procedures (15%), new retinal emboli were found. Two of the procedures with emboli had small retinal infarcts. Three of five were performed using CPDs versus seven of 28 that had no retinal emboli (P = not significant). Two of four patients (50%) with previous radiation therapy to the neck had new retinal emboli versus three of 29 patients (10%) who had no previous radiation therapy (P = 0.038). None of the other patient characteristics was associated with retinal embolization. In 30 (91%) of patients with an adequate acoustic temporal window for TCD monitoring, there was no statistically significant correlation between TCD data and the incidence of retinal emboli. No visual field defects were found. On long-term follow-up, all retinal emboli and retinal infarcts had resolved. Retinal embolization during CAS is not uncommon, and it occurs in both protected and unprotected procedures. Most retinal emboli are clinically silent.