Abstract WP059: Effectiveness of low-dose intravenous alteplase in acute central retinal artery occlusion

Introduction: Central retinal artery occlusion (CRAO) is an ophthalmic emergency with a poor visual prognosis after conservative management, highlighting the urgent need for effective therapy. However, randomized controlled trials of intravenous thrombolysis (IVT) using standard-dose alteplase (0.9 mg/kg) or tenecteplase have failed to demonstrate efficacy. In Japan, a lower-dose alteplase regimen (0.6 mg/kg) has been adopted in limited institutions for CRAO treatment. This study aimed to clarify the effectiveness and safety of low-dose intravenous alteplase for CRAO within 4.5 hours of onset. Methods: We retrospectively registered consecutive patients with non-arteritic CRAO or severe branch retinal artery occlusion (BRAO) who presented within 24 hours of onset at three Japanese centers, from the implementation of an acute CRAO care pathway at each site until September 2024. From this cohort, we extracted patients with baseline best-corrected visual acuity (BCVA) ≤ 20/200, presentation within 12 hours of witnessed onset, no proliferative retinopathy or cilioretinal artery, and available 30-day visual acuity data. We compared 30-day visual outcomes between patients treated with IVT and those without IVT. The primary outcome was BCVA ≥ 20/100 at 30 days; secondary outcomes included changes in logMAR and others. Results: Of 41 registered patients, 3 who received IVT and 21 who did not were excluded, leaving 17 eligible for analysis (mean age 71.4±13.4 years; 5 women; 14 CRAO). Among these, 9 patients received IVT with a median onset-to-needle time of 243 minutes (IQR 195–260). At baseline, 14 patients (82.4%) had visual acuity of counting fingers or worse. Baseline characteristics were generally balanced except for diastolic blood pressure on admission (median 82 vs 105 mmHg, p=0.016). At 30 days, the proportion achieving BCVA ≥ 20/100 was higher in the IVT group, though not statistically significant (22.2% vs 0%, p=0.471). However, improvement in logMAR was significantly greater in the IVT group (median 1.18 vs 0.45, p=0.036). One asymptomatic intracranial hemorrhage occurred in the IVT group, and one intraocular hemorrhage in the no-IVT group. Conclusions: Intravenous low-dose alteplase appeared safe and potentially more effective than conservative therapy for acute CRAO (including severe BRAO) within a 4.5-hour window in this small observational study. Larger prospective studies are warranted to validate these findings.