15.1Failed and Unadopted Treatments for Branch Retinal Vein Occlusion

15.1.1Sector Panretinal Laser Photocoagulation for Serous Retinal Detachment in Branch Retinal Vein Occlusion

Sector panretinal laser photocoagulation (PRP) has been used in a case series for serous retinal detachment after branch retinal vein occlusion (BRVO). Efficacy was suggested, but in the absence of a control group it is difficult to know if the outcomes after treatment are better than the natural history.48

15.1.2Laser Chorioretinal Venous Anastomosis for Branch Retinal Vein Occlusion with Macular Edema

LCRVA, originally devised for nonischemic CRVO with ME, has also been applied for nonischemic BRVO with ME, but no randomized controlled clinical trial has proven its efficacy in this setting, unlike the situation with CRVO.13 Successful anastomosis has been reported in 50% of treated cases, usually within 2 months of treatment.13 One to three lines of improvement has been reported in 33% of cases.13 Technical details of the procedure are the same as for CRVO (see Sect. 15.2.2). As of 2008, 11 cases treated with this technique had been reported in the literature, with a successful anastomosis created in 5% and 36% showing an improvement of two lines of VA at 1 year follow-up.15 It is little used for BRVO with ME since the advent of IVI of anti-VEGF drugs.15

15.1.3Intravenous Infusion of Tissue Plasminogen Activator

In a randomized trial comparing intravenous tissue plasminogen activator (TPA) versus isovolemic hemodilution in 11 patients with BRVO and ME reducing VA to less than 20/50 and presenting within 11 days of symptom onset, there was no difference in outcome between the two groups.22 The regimen was expensive, requiring 8 days of hospitalization. The first day, the patients receiving TPA were given 50 mg intravenously over 60 min with concomitant heparinization that continued for the 8 days in hospital. Patients also were treated with aspirin 100 mg/ days for 12 weeks. The dose of TPA used was lower than that used in treating acute myocardial infarction and patients over age 70 were excluded to reduce the risk of hemorrhagic events. Only 11 patients could be enrolled over 7 years at five clinical centers in Europe, perhaps because of the aggressiveness of the intervention.22

An experimental study in rabbits with BRVO induced by photothrombosis with Rose Bengal, 30%, used a much higher intravenous dose of TPA than the human studies.64 With 3 mg/kg of intravenous TPA, the investigators were able to show breakdown of the thrombus and restoration of blood flow. In addition to the higher dose of TPA, the TPA infusion was begun within 2 h of BRVO, a standard unlikely to be met in clinical practice.64

Efforts to lyse thrombus in BRVO with intravenous TPA have stopped because of its expense and lack of efficacy.

15.1.4Intravitreal Injection of Tissue Plasminogen Activator

In a rabbit model of BRVO, IVI of TPA did not improve reperfusion of retinal vessels subjected to laser-induced venous thrombosis.1 In cats, subretinal injection of TPA at concentrations less than 200 mg/l was not associated with histological