Reviewed by John J. Chen, MD, PhD
John J. Chen, MD, PhD, Professor of Ophthalmology and Neurology Mayo Clinic, Rochester, MN, advised caution as the best route when confronted with the scenario of an elderly patient presenting with acute visual loss. He participated in a debate on this topic at the 15th annual Controversies in Ophthalmology Congress in Athens.
A 67-year-old man presents with acute visual loss in the left eye on a late Friday afternoon. He was found to be count fingers, and examination showed retinal whitening and a cherry red spot, a classic finding in central retinal artery occlusion (CRAO).
Chen pointed out a clinician’s choice: perform ocular massage and anterior paracentesis with referral for a visit with the primary care physician (PCP) for an outpatient stroke workup OR immediately refer the patient to the emergency department (ED) or nearest stroke center.
The consequences of the first choice, the older traditional approach of in-office interventians and an outpatient referral to the PCP, will likely result in a lack of visual improvement. More importantly, the patient can suffer a significant stroke while awaiting a visit with the PCP. Only after the life-altering stroke would the cause of the stroke and CRAO be found, such as critical internal carotid stenosis, Chen explained.
If the physician opted for the second choice and sent the patient for immediate care in the ED, the patient could be given intravenous thrombolysis within 4.5 hours of vision loss, which can potentially lead to improvement in vision. Most importantly, during the ED visit, the patient will undergo an urgent stroke workup and a potential underlying cause can be immediately addressed, such as a carotid endarterectomy for significant carotid stenosis, which can prevent stroke.
Relevant CRAO facts
CRAO is typically an embolic event that requires an immediate stroke workup that includes imaging of the vessels in the head and neck, monitoring of the heart rhythm, and imaging of the heart with an echocardiography. CRAO is also rarely caused by giant cell arteritis.
Chen emphasized that symptomatic stroke occurs in 3% to 5% of cases within 2 to 4 weeks of the CRAO. This includes results from a Mayo Clinic cohort that showed a 5% risk of symptomatic stroke within 2 weeks of a CRAO.1-3 In addition, asymptomatic strokes can be visualized on magnetic resonance imaging (MRI) when RAO occurs in up to 24% of cases.
Chen described that these studies have led to a recent large paradigm shift in which CRAO is considered a stroke that warrants an urgent referral to the ED for acute cases to evaluate for potential causes of a stroke.4
Traditional conservative treatments, ie, ocular massage and anterior paracentesis, as might be chosen for the first treatment option, are ineffective and no longer endorsed in professional guidelines.5,6
Intravenous thrombolysis for CRAO is offered by many centers if the vision loss is within 4.5 hours based on retrospective studies. A recent meta-analysis showed that 44% of CRAO patients treated with intravenous thrombolysis had improvement in their visual acuity (VA) when they were treated within 4.5 hours of the event compared to 13.1% without treatment.6 Use of intravenous thrombolysis for CRAO is currently undergoing clinical trials.
The current Mayo Clinic protocol to address CRAO within 24 hours of the insult is referral to the ED where they are seen by neurology. If the vision loss is within 4.5 hours and VA is 20/200 or worse, the protocol activates the acute stroke pager and intravenous thrombolysis is offered if the patient has no contraindications, including no hemorrhage on CT and giant cell arteritis is ruled out.
For all acute RAOs, a head CT and carotid imaging are performed while in the ED. In addition, the patient is referred to the stroke Neurology outpatient clinic, where MRI brain scan, echocardiogram, and Holter monitoring are usually performed within 1 to 2 weeks.
Chen summarized, “An acute CRAO warrants an urgent referral to the ED or nearest stroke center, which provides the best chance of a potential intervention that may improve vision, and, most importantly, evaluation for a potential cause of the CRAO and prevention of an impending stroke.”