Abstract

SA.16.02

Effects on choroidal neovascularizations after Anti-VEGF upload using intravitreal ranibizumab as determined by spectral domain optical coherence tomography

Carsten Framme1, Georgios Panagakis1, Karsten Hufendiek1, Reginald Birngruber2
1Universitäts-Augenklinik, Klinikum der Universität Regensburg, Regensburg; 2Medizinisches Laserzentrum Lübeck, Universität Lübeck

Objective
It is unclear whether anti-VEGF monotherapy in AMD is able to achieve morphologic CNV regression or only stops further CNV growth. It was the aim of this study to image CNV structure before and after anti-VEGF treatment using spectral domain optical coherence tomography (SD-OCT).
Methods
Out of 60 consecutive patients a prospective CNV evaluation was possible in 53 patients using the Spectralis-OCT (Heidelberg engineering, Germany). Newly diagnosed CNV (classic CNV: n=12; occult CNV: n=36; minimal classic CNV: n=5) due to AMD were imaged before and 4 weeks after anti-VEGF upload with 3 intravitreal injections of Ranibizumab. Qualitative (structural changes) and quantitative measurements (diameter and thickness) of the CNVs were obtained from the OCT images using the Heidelberg Eye Explorer software. Statistical analysis for paired samples was performed using the t-test (SPSS for Windows 15.0).
Results
Classic CNV components were observed above the RPE/photoreceptor complex, whereas occult CNVs stayed below. 62% of all postoperative OCTs revealed complete dry retinal structures, in 25% edema reduced, and in 13% edema remained unchanged. Qualitatively, overall CNV architecture appeared to be unchanged in 79%, reduced in thickness in 19%, and became larger in 2%. Quantitatively, for all CNV subtypes the diameter of CNVs (preoperatively: 2961µm; postoperatively: 2946µm) did not change after treatment (classic CNVs: p=0.307; occult CNVs: p=0.472, minimal classic CNVs: p=0.116) independently of postoperative retinal edema. The overall thickness of the CNV; however, reduced from 203µm to 175µm (p=0,000). In CNVs with classic components (n=17) thickness regressed from 266µm to 208µm (p=0.001). In contrast, for occult CNVs thickness reduced insignificantly from 173.6µm to 158.4µm (p=0.060).
Conclusions
Using SD-OCT CNV size can be two-dimensionally determined and followed up after intravitreal anti-VEGF treatment. In only one case CNV enlargement was observed, whereas in about 80% CNV architecture appeared to be unchanged independently from retinal edema. Quantitative measurements underlined stable appearance for occult CNVs and revealed significant but small reduction of thickness but not of diameter for classic CNV components. Thus, Ranibizumab monotherapy is able to morphologically stop further CNV growth but does not lead to a regression of CNVs especially of its occult components.

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