How would obtaining a Transesophageal Echocardiogram (TEE) and Erythrocyte Sedimentation Rate (ESR) help determine if an eye has experienced amaurosis fugax?

From the Guidelines

Obtaining a TEE and ESR can help determine if an eye had amaurosis fugax by identifying potential underlying cardiac and inflammatory causes. A TEE is valuable for detecting cardiac sources of emboli that could cause temporary vision loss by occluding the retinal artery, as it can visualize cardiac structures in detail, potentially revealing atrial thrombi, valvular vegetations, or patent foramen ovale that might allow paradoxical emboli to reach the eye 1. The sensitivity of TEE in detecting vegetations and thrombi is high, ranging from 90% to 100%, making it a reliable noninvasive test for defining this disease 1. The ESR, meanwhile, is a non-specific inflammatory marker that can help identify inflammatory conditions like giant cell arteritis, which is a significant cause of amaurosis fugax in older adults, with an elevated ESR (typically >50 mm/hr) suggesting inflammation of the blood vessels supplying the eye. These tests are complementary - the TEE focuses on embolic sources while the ESR screens for inflammatory etiologies, and when combined with clinical history of sudden, temporary monocular vision loss, these diagnostic tools help differentiate amaurosis fugax from other causes of transient visual disturbances and guide appropriate treatment to prevent permanent vision loss or stroke 1. Some key causes of transient monocular blindness include carotid artery stenosis or occlusion, atherosclerosis, dissection, arteritis, radiation-induced arteriopathy, arterial embolism, cardiogenic embolism, atheroembolism, hypotension, intracranial hypertension, glaucoma, migraine, and vasospastic or occlusive disease of the ophthalmic artery 1. It is essential to consider the risk of stroke and permanent blindness in the affected eye as a result of the initial or subsequent episodes of amaurosis fugax, and to use the TEE and ESR results to guide appropriate treatment and prevent these complications 1. Key points to consider when interpreting the results of the TEE and ESR include:

• The presence of atrial thrombi, valvular vegetations, or patent foramen ovale on the TEE, which could indicate a cardiac source of emboli 1
• The level of elevation of the ESR, which could indicate inflammation of the blood vessels supplying the eye 1
• The clinical history of sudden, temporary monocular vision loss, which is essential for differentiating amaurosis fugax from other causes of transient visual disturbances 1.

From the Research

Diagnostic Approach to Amaurosis Fugax

Obtaining a Transesophageal Echocardiogram (TEE) and Erythrocyte Sedimentation Rate (ESR) can be helpful in determining if an eye has amaurosis fugax. The following points highlight the relevance of these tests:

• A TEE can help identify potential cardiac or proximal aortic sources for embolism, which may cause amaurosis fugax 2.
• ESR is a marker of inflammatory conditions and can be used to monitor chronic inflammatory conditions, whereas C-reactive protein (CRP) is more useful in diagnosis and monitoring responses to therapy in acute inflammatory conditions 3.
• Amaurosis fugax is a type of transient ischemic attack (TIA) that can be caused by emboli originating from the heart or aortic arch, making TEE a valuable diagnostic tool 4.
• Atrial fibrillation is a major cause of ischemic stroke and TIA, and investigation for paroxysmal atrial fibrillation is recommended following an embolic brain event, including amaurosis fugax 5.
• Heritable thrombophilia and hypofibrinolysis may also contribute to the development of amaurosis fugax, and ESR can be used to monitor inflammatory conditions that may be associated with these conditions 6.

Key Findings

• TEE was particularly helpful in identifying prominent aortic plaques, which can act as a potential source for retinal ischemia or embolism 2.
• ESR and CRP can be used to monitor inflammatory conditions, but it is essential to understand the physiologic principles behind these tests to use them appropriately 3.
• All TIAs, including amaurosis fugax, should be treated as medical emergencies, and patients should be expeditiously evaluated with a comprehensive diagnostic workup, including cardiac investigations and serum studies 4.
• Atrial fibrillation was found to be an underestimated cause of ischemic monocular blindness, and investigation for paroxysmal atrial fibrillation is recommended following an embolic brain event 5.
• Heritable thrombophilia and hypofibrinolysis may contribute to the development of amaurosis fugax, and further studies are needed to evaluate the prognostic and therapeutic relevance of these findings 6.