Novel Angiographic Features Associated with ICG Dye-Enhanced Photocoagulation of Choroidal Neovascular Membrane Feeder Vessels
P. Danzi1, G. Levi1, C. Veronese1, R. Flower2,3, G. Staurenghi4,1; 1Department of Ophthalmology, University of Brescia, Brescia, ITALY , 2Department of Ophthalmology, University of Maryland, Baltimore, MD ,3Department of Ophthalmology, New York University, New York, NY,4Department of Ophthalmology, University of Milan, Milan, ITALY

PURPOSE

To describe novel angiographic features following dye enhanced photocoagulation (DEP), a treatment modality for choroidal neovascular membrane feeder vessels by application of laser energy during dye transit.

METHODS:

24 patients were enrolled in a phase II randomized clinical trial to evaluate safety of DEP compared to feeder vessel treatment (FVT) using 810 nm laser alone (12 FVT / 12 ICG-DEP FVT). Indocyanine green angiography (ICGA) was performed using a prototype modified fundus camera and a commercial confocal scanning laser ophthalmoscope (Heidelberg HRA, Heidelberg, Germany). The prototype camera also made possible precise delivery of photocoagulation energy to CNV FVs upon arrival of a secondarily-injected, high-concentration ICG dye bolus in a targeted FV, as used in DEP. Fluorescein angiography (FA) was performed using a fundus camera and the HRA. At different times, one well-trained observer (GS) evaluated each of the two ICGA studies made in each patient using the two instruments.

RESULTS:

ICGA quality was comparable with both instruments. Of the FVs found in the 24 patients using the HRA, 92% (i.e., in 22 patients) were also found using the prototype camera. Difficulty in initially finding FVs in two patients with the prototype instrument was related to poor pupil dilation. However, during treatment with the prototype instrument, the target FVs in all 24 patients were identified. A consistent ICGA characteristic following DEP was that ICG dye remained in treated FVs immediately after their closure. Meanwhile, the FAs clearly demonstrated the complete closure of the lesions.

CONCLUSIONS:

These data suggest that the identification rate of FVs using the prototype instrument is similar to that obtained with a scanning laser ophthalmoscope. A novel angiographic feature found with the prototype instrument, using it to perform DEP, is presence of incarcerated ICG dye immediately following treatment as a sign of a complete FV closure.

Presented at: The Association for Research in Vision and Ophthalmology (ARVO), 2005 Annual Meeting, Ft. Lauderdale, Florida – May 1, 2005