A randomized controlled trial suggests that thrombolysis may enhance visual acuity in patients with central retinal artery occlusion (CRAO), also known as “eye stroke,” compared to oral aspirin, although results were not statistically significant. Dr. Benoit Guillon, the study’s lead author from Nantes University Hospital in France, noted that while patients treated with thrombolysis demonstrated greater improvement on vision test charts, the aspirin group performed better than anticipated, highlighting the study’s limited statistical power.
“Our findings are promising, as 17% more patients achieved visual recovery in the thrombolysis group,” Guillon explained to Medscape Medical News. Despite these findings, he recommended that until results from other ongoing trials are available, clinicians should assess each patient’s risk-benefit ratio before opting for thrombolysis.
The study’s results, part of the THEIA trial, were presented by Guillon on October 26 at the 16th World Stroke Congress (WSC) 2024.
CRAO and the Urgency of Treatment
CRAO is a rare and sudden cause of severe, painless vision loss in one eye. “Permanent damage often occurs within four hours, underscoring the need for immediate intervention, yet no treatment has been definitively validated,” Guillon said. He emphasized that approximately a third of CRAO patients also experience asymptomatic hemispheric ischemia, heightening their risk for future strokes. For these patients, he advised treatment within a stroke unit, ideally managed by stroke neurologists.
Earlier studies on thrombolysis for CRAO have shown mixed results. Observational studies were generally positive, but previous randomized trials indicated a risk of intracranial bleeding, particularly when treatment occurred more than 12 hours after symptom onset. However, meta-analyses suggest potential benefits for patients treated within 4.5 hours.
In 2021, the American Heart Association classified CRAO as a medical emergency and recommended thrombolysis as a possible treatment, pending high-quality trials. THEIA is the first of three new randomized trials testing early thrombolysis, with the other two, TenCRAOS and REVISION, expected to report results soon.
Study Findings and Safety Considerations
The THEIA trial, conducted across 16 French centers, enrolled patients with sudden and severe visual loss, confirmed by an ophthalmology department, followed by assessments in a stroke unit. Eligible patients were randomized to receive either intravenous alteplase with oral placebo or an intravenous placebo with oral aspirin.
The trial’s primary endpoint, an improvement in visual acuity at one month, was measured using the LogMAR scale, where 0 denotes perfect vision and 2.9 represents no light perception. On average, patients had a baseline LogMAR score of 2.4, with most unable to read any letters on the LogMAR chart. Thrombolysis was administered an average of 232 minutes post-symptom onset.
Both groups showed significant visual improvement at one month. Vision improved by -0.44 LogMAR in the aspirin group and by -0.62 LogMAR in the thrombolysis group. The primary endpoint of at least a 0.3 LogMAR improvement (three lines on the vision test chart) was achieved in 48.1% of the aspirin group and 65.5% of the thrombolysis group, though these results were not statistically significant (odds ratio 1.10; 95% CI, 0.07-18.39). One case of asymptomatic intracranial hemorrhage was reported in the thrombolysis group, with no such incidents in the aspirin group.
Advances in Early Treatment
During the presentation, Dr. Amit Kandel from the University at Buffalo emphasized the need for rapid treatment. He shared that his team has been using thrombolysis at their stroke unit over the past two years but found that delays in diagnosis by ophthalmologists posed challenges. To address this, they acquired an optical coherence tomography (OCT) scanner to diagnose CRAO directly and expedite treatment with tenecteplase.
Kandel added that quick intervention is crucial for thrombolysis efficacy and noted the need for further studies to determine when the cause of CRAO is due to a treatable thrombus rather than a calcified plug.
Guillon acknowledged that if thrombolysis proves effective, establishing optimal diagnostic tools and treatment protocols tailored to individual hospitals will be essential. The discussion also addressed whether brain imaging should be required before thrombolysis in CRAO patients. Guillon suggested that brain imaging might be beneficial, as around one-third of patients present with intracranial ischemia. However, some experts argued that asymptomatic ischemia should not preclude thrombolysis, as skipping brain imaging might save valuable treatment time. Guillon noted that this consideration warrants future investigation if thrombolysis is confirmed effective.
The THEIA trial received funding from the French Ministry of Health, Boehringer Ingelheim, and Nantes University. Guillon reported no conflicts of interest.
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