The 2021 Meeting of the ASRS — representing a return to a live meeting after a year and a half worldwide pandemic — has concluded.
Presenters outlined new treatment strategies for conditions for which we have no effective therapies. There were also several reports on clinical trials testing compounds designed to enhance our abilities to treat conditions for which effective treatments already exist.
One study that caught my attention was a possible new therapy for an age-old devastating condition for which we have no reliable, effective treatments: central retinal artery occlusion (CRAO).
Historically, CRAO occurs at a rate of approximately 2 / 100,000 people a year. The loss of vision is sudden, severe, and painless. Long-term studies demonstrate poor vision of count fingers or worse for more than 80% of patients who develop the condition and return of vision to better than 20/100 in less than 20%. The pathology of the disease can be likened to that of a cerebrovascular accident (CVA) in which an embolus — usually cholesterol derived — occludes a major vessel in the brain, leading to the typical symptoms of CVA: loss of movement, loss of sensation, headache, difficulty with speech, and difficulty with ambulation. When the embolus occludes the central retinal artery, a branch of the ophthalmic artery, it deprives the retina of blood flow, and visual function diminishes suddenly.
Recent advances in CVA care have led to the establishment of neurovascular ED centers with on-call “stroke teams” to treat CVA within the first few hours of presentation. Evaluation includes focused, in-depth medical evaluation and neuroimaging followed by therapy, which can consist of tPA and embolectomy depending on the specifics of the individual case.
In the presentation by Dr. Lema at ASRS on CRAO, an observational study demonstrated a meaningful improvement in vision in CRAO patients. In the report, physicians treated CRAO patients within the first 12 hours of their CRAO event.
The on-call stroke team performed an eye exam — including vision check, fundus photos, and OCT images — and relayed the results via telemedicine to an on-call retina specialist who confirmed the diagnosis. For the patients in whom the retina specialist confirmed CRAO, the ED stroke team obtained an arterial angiogram and injected intra-arterial tPA.
Overall, the ED stroke team treated 15 patients. Ten out of 15 (66%) had improvement, and 8/15 (53%) had three or more lines of improvement. Remarkably, four patients with vision starting between count fingers and no light perception improved to 20/80 or better.
These results mirror three other observational reports on intravenous tPA administration that led to an overall 3-line improvement in approximately 50% of patients. It also represents an advance of the forefront of CRAO treatments after the EAGLE study (which evaluated intraarterial tPA for CRAO) was terminated early due to low effectiveness.
Although promising, these data are merely observational and call for a more formal randomized clinical trial. With the advent of dedicated ED stroke centers and telemedicine capabilities, ED centers can team up with telemedicine clinicians to include retinal physicians and provide emergency care for these devastating retinal emergencies.
Dr. Hamilton has been part of numerous clinical trials.
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