Abstract
Purpose: :
to define new criteria for the selection of AMD patients undergoing RPE-choroid (PATCH) transplantation and to increase predictability of PATCH revascularisation by examining fine anatomic features using spectral-domain OCT (SD-OCT) and ICGA.
Methods: :
Retrospective analysis of images from 22 eyes of 22 patients obtained using Heidelberg Spectralis HRA + OCT and reviewed to evaluate pre-operative foveal integrity of: outer nuclear layer (ONL), external limiting membrane (ELM), internal segment-external segment junction (IS-OS) and minimum foveal pre-operative retinal thickness. Based on last follow-up visual acuity test (VA), patients were divided into 2 groups: "improved" (≥1 line) and "not-improved" (stable or worsened). The correlation between the 2 groups and SD-OCT features was studied. ICGA were evaluated to determine the time of revascularisation of the PATCH, the location of the site of harvesting (SoH) and the distance SoH-fovea. SoH choroidal thickness was measured on SD-OCT obtained nearby. Patients were divided into 2 groups: "revascularized" (revascularization < 30 days) "not-revascularized" (revascularization > 30 days or never). The correlation between the 2 groups and described features was studied.
Results: :
VA improved in 10 patients while 12 patients worsened or remained stable. Mean minimum foveal thickness was not statistically different between the 2 groups. "Improved" showed a correlation with the integrity of ONL (P=0.04), ELM (P=0.0005), IS-OS (P=0.006) (Fisher’s exact test alpha<0.05). The mean revascularisation time in "improved" (15.20 days ±6) was lower compared to "not-improved" (25.75 days ± 26), but not statistically significant. 17 patients were classified as "revascularized" while 5 as "not-revascularized" . No correlation was found with the location of SoH and the distance SoH-fovea. Thickness of the choroid at SoH in "revascularized" (175 µm ± 49) was statistically higher compared to "not-revascularized"(101 µm ± 13) (Mann-Whitney test P=0.006).
Conclusions: :
In PATCH transplantation best functional outcome is correlated to the preservation of macular function combined with a functioning RPE-choroid graft. Foveal examination of ONL, ELM and IS-OS integrity using SD-OCT may represent a feasible method for the selection of patients. Choroidal thickness measured with SD-OCT in the SoH could be a useful predictor of PATCH revascularisation
Keywords: transplantation • retinal pigment epithelium • age-related macular degeneration