Abstract
Abstract: :
Purpose: To evaluate the feasibility, safety and efficacy of local thrombolytic agents directly injected into the occluded retinal vein in an experimental model of retinal vein occlusion. Methods: Experimental branch retinal vein occlusion was created photo-chemically using intravenous injection of rose bengal followed by diode laser photocoagulation in 6 eyes of 6 dogs. Three eyes were treated by retinal vein cannulation and injection of t-PA using a specifically designed microcatheter and the remaining 3 eyes were left as an untreated control group. The total amount of t-PA injected intravenously was 1 cc (1 mg/cc) using an average pressure of 40 psi resulting in an average injected flow rate of 0.05 cc/min. Evaluation was performed by clinical examination, fluorescein angiography and histological examination. Main outcome measures: achievement of prolonged intravascular infusion of t-PA, changes in the fundus appearance, fluorescein angiography and histology. Results: Cannulation with subsequent infusion of t-PA for a period of at least 30 minutes was achieved in all-3 treated eyes without any complications observed in the follow-up period. . One week and one month postoperatively, marked decreases in retinal hemorrhage , retinal veins dilatation and tortuosity were noted in all treated eyes. All non-treated eyes presented with persistent retinal hemorrhage, vascular dilation and tortuosity within the same follow-up period. Histologic analysis confirmed the presence of thrombi in non-treated eyes while no thrombi was observed in t-PA treated eyes. Fluorescein angiography demonstrated improved circulatory flow in treated eyes. Conclusion: Retinal vein cannulation with prolonged intravascular injection of t-PA is feasible and safe. This surgical technique may offer a new treatment option for patients with retinal vein occlusion.
Keywords: 615 vascular occlusion/vascular occlusive disease