麻豆传媒

A remote consult protocol using point-of-care automated optical coherence tomography (OCT) for the rapid treatment of retinal artery occlusions proved successful in a small group of patients, according to a retrospective case series.

There was a statistically significant improvement in mean visual acuity from logarithm of the minimum angle of resolution (logMAR) 2.14 to logMAR 0.7 within 24 hours after treatment with intra-arterial tissue plasminogen activator (tPA) (P=0.0001) and logMAR 1.04 after 4 weeks (P=0.01), reported Richard Rosen, MD, of the New York Eye and Ear Infirmary of Mount Sinai in New York City, and colleagues.

Of 59 evaluated patients, 42% had confirmed retinal artery occlusions, also known as eye strokes, and nine received treatment within an average 146 minutes from presentation. Clinically significant improvement was observed in 66% of patients within 24 hours and maintained through 1 month in 56% of all treated patients, they noted in .

While there's no control group for comparison, "everyone has been impressed by the impact that this protocol has had on making the diagnosis more quickly, and getting patients to treatment faster," co-author Gareth Lema, MD, PhD, of the Icahn School of Medicine at Mount Sinai and New York Eye and Ear Infirmary of Mount Sinai, told 麻豆传媒. "This is giving us a lot of insight into what may be necessary to develop protocols not just for artery occlusion but other ophthalmologic emergencies as well."

Eye strokes, caused by blood clots in retinal arteries, are rare but can cause blindness. Patients tend to be in their 60s and 70s and have cardiovascular risk or heart disease, Lema said. "Only about 20% of patients will recover any sort of useful vision."

Standard treatment is therapy with clot-busting drugs, either intravenous or intra-arterial tPA. However, the only support for these strategies comes from observational studies, said John Chen, MD, PhD, of the Mayo Clinic in Rochester, Minnesota, in an interview.

Randomized trials are in the works to offer more insight into the value of the treatments, said Chen, who wasn't involved in the study. A couple other treatments have been tried, but they haven't worked, he noted.

In eye strokes, research has suggested that tPA must be given within 4.5 hours (intravenous) or 12 hours (intra-arterial) of the last time the patient had normal vision, Lema said.

Prior to the new protocol at three Mount Sinai stroke centers, ophthalmologists dilated the eyes of suspected eye stroke patients and evaluated them, Lema explained. But the ophthalmologists might be delayed if they were at a hospital or they may be on call and would have to come in. "It really delayed care quite a bit," he said.

Under the new protocol, the system deployed OCT scanners and set up a virtual consultation system in which on-call ophthalmologists can instantly make diagnoses based on images. It takes about 2 minutes for an eye scan, Lema said, and "we can take the patient directly to treatment" if an ophthalmologist diagnoses a retinal occlusion.

While the researchers haven't yet published comparison data, Lema said the time from arrival to treatment has shrunk from a mean of about 350 minutes to 146 minutes, a savings of 2 hours.

As for cost, Lema said the OCT scanners cost $40,000 each, and the health system received support from a grant to buy them.

Chen said he likes how the protocol quickens the time to treatment, and he added that photographic documentation from the scans will be helpful. As for feasibility, he said the protocol may be the best fit for academic centers with large stroke clinics.

However, he cautioned that until more evidence supports the use of clot-busting drugs in eye stroke, "maybe people aren't going to be that committed" to buying OCT scanners.

For the study, the researchers tracked suspected eye strokes at three stroke centers for 18 months starting May 1, 2021. All patients with diagnosed eye strokes were treated with intra-arterial tPA, since none arrived within the recommended 4.5 hours after last known normal vision for intravenous tPA to be administered.

Per the protocol, 2-mg aliquots were injected every 5 minutes until the patient noted visual improvement, a restoration of the choroidal blush was observed on the cerebral angiogram, and/or a maximum dose of 22 mg was reached. The mean dose was 16 mg.

Comment