The role of choroidal optical coherence tomography for follow-up of carotid cavernous fistula with anterior drainage

Abstract

Background: To evaluate the role of the choroidal vascularity index (CVI) and the tortuosity index (TI), along with choroidal thickness measurements, in follow-up for anteriorly draining carotid cavernous fistulas (CCF) that would otherwise necessitate an invasive carotid angiogram. Methods: In this longitudinal observational study, analysis of enhanced depth imaging spectral domain optical coherence tomography (SD-EDI-OCT) images of 22 patients with angiographically proven unilateral CCF with anterior drainage was performed for subfoveal choroidal thickness (SFCT), central foveal thickness (CFT), CVI and TI. Baseline measurements were compared with those taken at the last visit after occlusion of the fistula. Results: Both in the clinically affected and unaffected eyes, there was a significant decrease in CFT (p = 0.015 and p = 0.005, respectively), SFCT (p = 0.000 for both eyes), CVI (p = 0.002 and 0.001, respectively) and all three TI parameters, including inferior (p < 0.001 and p = 0.01, respectively) and superior temporal vein tortuosity index (p = 0.005 and p = 0.02, respectively) as well as total venular tortuosity index (p < 0.001 and p = 0.002, respectively) after successful closure of the fistula compared to first presentation. Changes in all parameters were similar between the D-CCF and I-CCF groups except for CVI. Conclusions: In this first study concerning follow-up of anteriorly draining unilateral CCFs by SD-EDI-OCT, we not only demonstrated involvement of the clinically unaffected eye but also showed that, this modality, utilizing CVI and TI together with choroidal thickness measurements, can be used as a readily available, noninvasive first-line followup method for evaluating occlusion of fistulas by endovascular treatment or spontaneous resolution.