Progression of Pachychoroid Neovasculopathy into Aneurysmal Type 1 Choroidal Neovascularization or Polypoidal Choroidal Vasculopathy

Abstract

To describe the progression of pachychoroid neovasculopathy (PNV) into pachychoroid aneurysmal type 1 choroidal neovascularization (PAT1)/polypoidal choroidal vasculopathy (PCV). Retrospective longitudinal cohort study. Patients diagnosed with PNV with a follow-up of ≥2 years. Multimodal imaging, including OCT and fluorescein and indocyanine green angiography, was reviewed for the presence of choroidal neovascularization (CNV), aneurysms within/at the margins of the CNV, and subfoveal choroidal thickness (SFCT). Rate of PNV to PAT1/PCV conversion and risk factors thereof. In total, 37 eyes of 32 patients with PNV with a mean follow-up of 3.3 ± 1.1 years (range, 2.0-5.2) were included in the study. At PNV diagnosis, the mean age was 59.7 ± 8.7 years (range, 38.5-78.0 years) and mean SFCT was 357 ± 92 μm (185-589). During the follow-up, 5 (13.5%) eyes developed aneurysms after a mean 3.4 ± 0.8 years (2.3-4.2), defining PAT1/PCV. The risk of PAT1/PCV conversion was 7.4% at year 3, 13.6% at year 4, and 30.7% at year 5. A mean of 5.2 ± 4.0 to 7.9 ± 3.6 intravitreal anti-VEGF injections were given per year, resulting in a significant reduction of SFCT to 317 ± 104 μm (122-589) (P= 0.0007). The age at diagnosis of PNV was significantly lower in eyes that later went on to develop PAT1/PCV (54.0 ± 5.6 [45.9-60.5] vs. 61.2 ± 8.4 [38.5-78.0] years; P= 0.025). At the end of the follow-up, SFCT had on average decreased by-14.0% ± 17.6% (-55.9% to 23.1%) in the PNV group, whereas it had increased by mean 6.9% ± 4.4% (0.00%-10.8%) in the PAT1/PCV conversion group (P= 0.0025). PNV can develop aneurysms within its type 1 CNV, defining the conversion to PAT1/PCV. In this study, the conversion to PAT1/PCV was seen in 13.5% of eyes, resulting in Kaplan-Meier estimates of risk for conversion of 7.4% at year 3, 13.6% at year 4, and 30.7% at year 5. Younger age at diagnosis of PNV andsustained choroidal thickening despite anti-VEGF therapy might be risk factors for PNV to progress into PAT1/PCV.