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Changes in confocal indocyanine green angiography through two years after photodynamic therapy with verteporfin
Ursula M Schmidt-Erfurth1, Stephan Michels
1University Eye Hospital, Medical School Luebeck, Ratzeburger Allee 160, D-13538 Luebeck, Germany. uschmidterfurth@ophtha.mu-luebeck.de
Purpose:
To evaluate vascular changes documented by confocal indocyanine green angiography (ICGA) through 2 years after photodynamic therapy (PDT) with verteporfin of neovascular age-related macular degeneration (AMD).
Design:
Single-center, 2-year, randomized, double-masked, interventional, placebo-controlled trial (subset from Treatment of AMD with PDT Study [TAP]).
Participants:
Sixty patients with subfoveal choroidal neovascularization (CNV) resulting from AMD.
Intervention:
Patients were randomized in a ratio of 2:1 to a standard regimen using verteporfin therapy at a drug dose of 6 mg/m(2) body surface area and a light dose of 50 J/cm(2) or a sham treatment with placebo infusion and light exposure. Retreatments, if persistent fluorescein leakage from CNV was documented, were scheduled at 3-month intervals for up to 2 years. Confocal ICGA with tomographic sections was performed at baseline and continuously at the month 3, 6, 12, and 24 examinations using a standardized protocol.
Main Outcome Measures:
Analysis included the size of the neovascular net, the area of late hyperfluorescence, and choroidal hypofluorescence during early- and late-phase imaging.
Results:
In the verteporfin-treated group, the mean size of the CNV and the mean area of late leakage consistent with active leakage or staining showed no further enlargement at month 12 and were reduced at month 24. In the placebo-treated group, new vessels grew threefold compared with baseline and exhibited persistent late hyperfluorescence resulting from leakage at 24 months. Associated choroidal hypofluorescence within the treated area was significantly increased in eyes treated with verteporfin PDT compared with the control group during the first year, persisted during all ICGA phases, and was irreversible during follow-up. Image analysis revealed choroidal hypoperfusion with choriocapillary dropout, which correlated with chorioretinal atrophy clinically. Progressive destruction of choroidal integrity by fibrosis in control eyes led to a similar extent of collateral hypofluorescence in both groups through the 24-month examination.
Conclusions:
Indocyanine green angiography is an important adjunct in the identification of vascular effects associated with verteporfin PDT. Repeated treatments effectively arrested CNV growth and reduced leakage activity. The collateral impairment of choroidal perfusion appears to influence the visual outcome of the treatment.