Session Title: FP-14 Vascular Diseases and Diabetic Retinopathy IV
Session Date/Time: Saturday 13/09/2014 | 16:30-18:00
Paper Time: 16:54
Venue: Boulevard F
First Author: : U.Schraermeyer GERMANY
Co Author(s): :
This study reports the clinicopathologic findings of leaky sites in pathological vessels after submacular removal of choroidal neovascular membranes (CNV). As the site that causes fluid exudation from neovascular vessels is unknown, specific attention was focused on the formation of fenestrations, cellular junctions and morphologic alteration which can cause endothelial leakage.
Section of Experimental Vitreoretinal Surgery, Centre for Ophthalmology, Tuebingen, Germany
Choroidal neovascular membranes of 15 patients who underwent submacular surgery for CNV were investigated. Each five patients received bevacizumab treatment or photodynamic therapy before surgery. All membranes were embedded for transmission electron microscopy. CNVs were analyzed for pathological cell to cell connections, fenestrations or other pathological conditions which can cause leakage of plasma.
The morphology of the newly formed blood channels was very variable and in principle was not different in treated and untreated patients. The sources of leakage in neovascular choroidal vessels were caused by insufficient endothelial cell connections and by capillaries with microvillar projections into the vessel lumen which blocked cellular perfusion but still allowed the flow of plasma. Fenestrations were only infrequently observed.
A newly discovered type of pathological capillary, called a labyrinth capillary, is very likely responsible for the permanent leakage of fluid. Due to the small vessel lumen, thrombocytes cannot enter these capillaries to close the leakages. Fenestrations did not appear to play a significant role in vascular leakiness.