Is the Presence of Blood a Reliable Indicator of CNV Subtype and Activity? Report From the UK VPDT Cohort Reading Centre Network

Abstract

Purpose:: To report on the relationship between subretinal and sub-retinal pigment epithelial (RPE) blood and activity of choroidal neovascularisation (CNV) on fluorescein angiography (FA) as judged by trained graders.

Methods:: Protocol colour photography and FA images from 45 treating centres in the UK VPDT Cohort Study were graded by trained and accredited personnel in the UK Reading Centre Network (Belfast, Liverpool and London). The study is a prospective, post-licensing cohort study enrolling patients undergoing treatment with verteporfin photodynamic therapy in the UK.

Results:: In 4980 graded angiograms, subretinal blood was present in 2305 (46.3%) and sub-RPE blood in 296 (5.9%). 12.8% (296) of cases with subretinal and 8.8% (26) of cases with sub-RPE blood were found to be inactive on the FA. Of eyes with subretinal blood, 87% (1766 out of 2305) were found to have a classic component. 54 % (1242 out of 2305) were graded as predominantly classic without occult. In eyes with sub-RPE blood, 67 % (199 out of 296) had a classic component and 45% were predominantly classic without occult.

Conclusions:: The presence of blood on a colour image indicates the lesion is more likely to be an active CNV: only one eighth of cases with either sub-retinal or sub-RPE blood had inactive CNV on FA. In eyes with sub-retinal blood, the lesion was more likely to comprise classic without occult CNV. When determining the requirement for PDT treatment, the presence of blood cannot be considered in isolation to be a marker of CNV activity indicating the need for FA to allow accurate assessment.

Keywords: age-related macular degeneration • imaging/image analysis: clinical • photodynamic therapy