The authors observed an unusual closed loop-like vessel formation in the macula and describe its regression caused by the heterogenous treatment effects of intravitreal ranibizumab injections in an eye with exudative age-related macular degeneration associated with multiple retinochoroidal anastomoses.
Unusual Loop-Like Vessel Formation After Intravitreal Ranibizumab Injections in AMD
From the Vitreous-Retina-Macula Consultants of New York, New York, New York, and the LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear, and Throat Hospital, New York, New York.
The authors have no financial or proprietary interest in the materials presented herein.
Address correspondence to Jason S. Slakter, MD, Vitreous-Retina-Macula Consultants of New York, 460 Park Avenue, 5th Floor, New York, NY 10022.
Accepted: October 14, 2008
Posted Online: March 09, 2010
Introduction
We observed an unusual closed loop-like vessel formation and its regression in the course of multiple intravitreal ranibizumab injections in an eye with exudative age-related macular degeneration. The development of such unique vessel formation might be attributed to the heterogenous treatment effect of ranibizumab on the choroidal neovascular components.
Case Report
A 76-year-old healthy woman was referred with the diagnosis of exudative age-related macular degeneration in both eyes. She had a treatment history of transpupillary thermotherapy in both eyes, two sessions of verteporfin photodynamic therapy combined with intravitreal steroid injection, an intravitreal bevacizumab injection, and an intravitreal ranibizumab (Lucentis; Genentech, Inc., San Francisco, CA) injection in only the left eye.
In October 2006, the right eye showed a large disciform scar in the macula. The left eye showed subfoveal choroidal neovascularization surrounded by subretinal fluid, subretinal hemorrhage, and lipid exudates (Figure). On biomicroscopic examination, the left eye demonstrated a large-size vessel on the surface of the central fibrotic scar. The large-size vessel originated from the grayish, active choroidal neovascularization lesion and had a bifurcation connecting to two separate sites of retinochoroidal anastomoses, seemingly functioning as a feeder choroidal vessel.1
After an intravitreal ranibizumab injection (0.5 mg) in December 2006, exudation from the active choroidal neovascularization component had markedly resolved. In addition, the ingrowth site of the presumed feeder choroidal vessel had regressed, leading to formation of an unusual closed loop-like vessel in the macula. The loop-like vessel was similar in diameter to the connecting retinal arteriole and venule. One month after an additional ranibizumab injection (0.5 mg), the loop-like vessel had disappeared, leaving one retinochoroidal anastomosis site.
Discussion
Retinochoroidal anastomoses are characteristic findings in end-stage age-related macular degeneration. The branching feeder choroidal vessel in our case might be acting as a form of compensation for the demand of the blood supply from the two separate anastomotic sites. Recently, intravitreal ranibizumab injection has been shown to be a promising therapeutic approach for the treatment of exudative age-related macular degeneration.2 After one intravitreal ranibizumab injection, the active choroidal neovascularization component and the ingrowth site of the feeder choroidal vessel appeared to be selectively obliterated with the retention of two sites of retinochoroidal anastomosis. As a result, the unusual closed loop-like vessel might then have developed.
Furthermore, taking into consideration the diameter of the loop-like vessel, it was most likely that this unusual vessel was fed and drained only by the retinal circulation, without participation of the choroidal circulation. Conclusions regarding the pathophysiologic implications of this case are limited by the fact that this is a single case report and the lack of sequential high-speed indocyanine green angiograms that may have better delineated the exact contributions of the two circulatory systems.
We observed an unusual loop-like vessel formation and its regression caused by the heterogenous treatment effects of intravitreal ranibizumab injections on the choroidal neovascularization associated with multiple retinochoroidal anastomoses.
References
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- Rosenfeld PJ, Brown DM, Heier JS, et al. Ranibizumab for neovascular age-related macular degeneration. N Engl J Med. 2006;355:1419–1431. doi:10.1056/NEJMoa054481 [CrossRef]