Angiographic and flow patterns of retinal choroidal anastomoses in age-related macular degeneration with occult choroidal neovascularization

Abstract

Objective To identify the angiographic features of retinal choroidal anastomoses (RCAs) in patients with newly diagnosed occult choroidal neovascularization (CNV) in the setting of age-related macular degeneration (AMD) and to determine the sequence of flow between the RCA and the CNV. Design Retrospective cross-sectional study. Participants The angiograms of 205 eyes of 153 consecutive patients with occult CNV on fluorescein angiography (FA) and focal hot spots on indocyanine green angiography (ICGA) were evaluated retrospectively. Methods of testing Red-free photographs and sequential digital fluorescein and indocyanine green angiograms obtained by confocal scanning laser ophthalmoscope (the Heidelberg Retina Angiograph; Heidelberg Engineering GmbH, Dossenheim, Germany). Main outcome measures The angiograms were evaluated for the presence of RCA. The following angiographic characteristics were recorded: number and type of anastomoses, location, distance from fovea, area of CNV, presence of pigment epithelium detachment (PED), cystoid macular edema on FA, and intraretinal leakage on ICGA. The direction of flow between the RCA and the CNV was identified by analyzing high-speed angiograms. Results Retinal choroidal anastomoses were identified in 57 eyes (28%), in 49 of 154 eyes with PED (32%), and in 8 of 51 eyes without PED (16%). Of 109 anastomoses, 70% were venous and 30% were arterial. Ninety-six percent of the eyes had at least one venous anastomosis, 49% of the eyes had an arterial anastomosis, and 46% of the eyes had both. Cystoid macular edema was seen on FA in 37 eyes (65%), and intraretinal indocyanine green leakage was noted in 52 eyes (91%). Twenty-two eyes that underwent high-speed ICGA were analyzed for the direction of flow. All 15 eyes having arterial and venous anastomoses demonstrated a filling pattern from the retinal arteriole to the CNV, followed by the retinal venule. Seven eyes with venous RCA showed flow sequence from the CNV to the collecting retinal venule. Conclusions Our study supports the presence of RCA in the early stages of acute exudative AMD with occult CNV, mainly with serous PED. High-speed angiography helps to identify the filling sequence of the RCA and the CNV, and therefore may guide the clinician in planning treatment strategies.