Authors: Shinsuke Yoshida; Soichi Oya; Masamichi Endo; Tsukasa Tsuchiya; Takumi Nakamura; Masahiro Indo; Masaaki Shojima; Toru Matsui (Kawagoe, Japan)

Introduction: It is well known that cervical internal carotid artery (cICA) stenosis can cause ipsilateral amaurosis fugax. Apart from this acute clinical problem, however, the visual impairment of chronic retinal ischemia due to cICA stenosis remains to be elucidated. In this study, we investigated whether the increased chorioretinal blood flow (CRBF) renders the improvement chronic visual deficit improves after carotid endarterectomy (CEA). Methods: We prospectively enrolled patients who underwent CEA from 2015 to 2018. We measured the CRBF by laser speckled flowgraphy (LSFG) before and after CEA, and analyzed the relationship of the increase of CRBF and postoperative visual recovery. Visual recovery was assessed by subjective improvement and quantitative visual acuity measurement using CSV1000 (Vector Vision). The CRBF approximated by Mean Blur Ratio (MBR) was calculated in the papillary vascular and tissue area by LSFG. Results: The MBR measured in 41 consecutive patients who had CEA. The ipsilateral MBR were 33.5±8.0 in the vascular area and 10.3±2.2 in the tissue area before surgery, significantly increased to 38.2±9.4 and 11.5±3.4 after surgery (p=0.0005, p=0.002). As for visual function, the ipsilateral additional value of CSV1000 was 15.3±7.0, and significantly improved to 18.2±6.7 (p=0.006). 23 patients (56.1%) reported subjective visual improvement, which was more frequently observed in patients with the improvement of CRBF (p=0.009). Increased CRBF of affected papillary tissue area after CEA was significantly associated with visual acuity improvement measured by CSV-1000 (p=0.018). Conclusion: CEA for cICA stenosis increases the CRBF. Postoperative subjective and objective visual improvement was significantly associated with the increase of CRBF. Based on our results, CEA might contribute to restoring the chronic visual deficit in patients with cICA stenosis that cannot otherwise be explained by ophthalmological diseases.