The Incidence of Neovascular Subtypes in Newly Diagnosed Wet Age-Related Macular Degeneration

Abstract

 

Purpose

 

To determine the frequencies of neovascular lesion subtypes in newly diagnosed neovascular age-related macular degeneration (AMD) and to determine whether these frequencies differ when grading is based on fluorescein angiography (FA) or both FA and optical coherence tomography (OCT).

 

Methods

 

We retrospectively analyzed a consecutive series of patients treated by a single physician with intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy for the diagnosis of neovascular AMD from January 2006 through January 2012 in order to identify newly diagnosed treatment-naïve cases. Inclusion criteria included: age over 50 years; best corrected visual acuity of 20/40 to 20/800, new onset of treatment-naïve CNV, and absence of permanent structural damage to the central fovea. Two independent graders classified the lesions based on FA [poorly defined (occult), well-defined (classic), or retinal angiomatous proliferation (RAP)] and with both FA and OCT [type 1 (sub-RPE), 2 (subretinal) or type 3 (intraretinal) neovascularization]; a third grader evaluated the lesion in the presence of significant discrepancies. Analysis between agreement in lesion subtype by FA alone or FA/OCT was performed using Chi-squared for two categorical variables. For each subtype of CNV, the association between demographic factors was also assessed. Analysis was performed using Stata 11 software (StataCorp, College Station, TX).

 

Results

 

Among 748 AMD patients treated with anti-VEGF therapy, a total of 531 eyes were treatment-naive and 311 fit the inclusion criteria. The average age at first injection was 81.5 years. 68.5% were women and 31.5% men. 95.5% were Caucasian, 2.9% Hispanic, and 1.9% Asian or Black. Based on FA classification alone, 47.9% had occult, 9.5% classic, 35.1% RAP, and 7.4% had mixed CNV lesions. In comparison, using FA/OCT, we found 43.4% type 1, 8.8% type 2, 36.4% type 3 (RAP), and 11.4% mixed. Subset analysis of the demographic variables and frequency for each CNV type demonstrated no significant differences.

 

Conclusions

 

With both forms of grading, we found a much higher incidence of type 3 (RAP) lesions and lower incidence of type 2 (classic) lesions than found in prior studies. Combined FA/OCT grading identifies a higher frequency of mixed CNV lesions as the addition of OCT appears useful in clarifying the location of the neovascular tissue in relation to the RPE.

 

Keywords: 412 age-related macular degeneration • 453 choroid: neovascularization • 550 imaging/image analysis: clinical