What Is a Carotid Artery Occlusion?

Occlusion or stenosis of the carotid arteries can lead to insufficient blood supply to the brain and eyes, resulting in a range of brain and eye symptoms. Studies have now shown that such fundus changes are not due to venous stasis, but due to carotid artery obstruction or stenosis caused by long-term insufficient perfusion of the ophthalmic artery is called hypoperfusion retinopathy. Carotid artery occlusion can also cause anterior ischemia of the eye, which is known as ocular ischemia syndrome along with fundus changes. If the various emboli from the carotid artery atheromatous plaques enter the retinal circulation, they can cause acute embolism to cause central retinal artery occlusion or branch occlusion, and can also enter the posterior ciliary artery and cause ischemic optic neuropathy and choroid Lesions.

Basic Information

Visiting department: Ophthalmology
Common locations: eye

Common causes: Occlusion or stenosis of the carotid artery leads to chronic hypoperfusion of the ophthalmic artery
Common symptoms: Transient darkening, sudden painless monocular vision loss; retinal edema thickening in the macular area, lowering of central eye arterial pressure, etc.

Causes of arterial occlusion or stenosis retinopathy

Ocular artery perfusion due to chronic obstruction or stenosis of the carotid artery results in pathological changes of the fundus.

Microemboli movement

The microemboli shed from the internal carotid atherosclerotic plaque enter the larger arteries of the retina, and the flow can be seen. When moving to the periphery, vision and visual field are restored.

Vasospasm

It is not easy to find that the fundus retina and blood vessels are usually normal.

3. Insufficient blood flow

Due to carotid stenosis or obstruction, the blood flow is insufficient, resulting in a decrease in retinal arterial pressure. Light pressure on the retinal arteries of the eyeball will result in no blood flow. If the pressure is lower than the intraocular pressure, the arteries will collapse without blood columns. No retinal arterial pressure was detected.

Clinical manifestations of arterial occlusion or stenosis retinopathy

There are different clinical manifestations depending on the carotid artery obstruction or stenosis, unilateral or bilateral, and the severity of the obstruction.

Transient sex

Many eye diseases can cause transient darkening, but this is the most common symptom of carotid obstruction or stenosis. Its clinical feature is sudden and painless monocular vision loss. Began to cover your eyes like a black screen, suddenly blind from top to bottom or from bottom to top. It lasts for a few seconds or 1 minute, and there are people who have been up to several minutes. The frequency of vision usually returns to normal after the attack. , Frequent attacks later, can be 10 to 20 times a day.

2. Hypoperfusion retinopathy

Also known as hypotensive retinopathy is chronic retinopathy due to chronic insufficiency of the ophthalmic artery, which results in long-term reduction of retinal arterial pressure. Its incidence is 5% to 12% of carotid artery obstruction or stenosis. Vision is slightly reduced in the early stage, and in the late stage or with complications, the visual field can be significantly reduced, and ipsilateral hemianopia can occur. ERG checks for b-wave reduction. Fundus examination: The optic disc is normal in the early stage, and the optic disc is pale due to insufficient blood supply in the late stage. The macula is normal or the central light reflection disappears. In severe cases, hyporetinal edema is increased due to the increased permeability of capillaries around the macula. The retinal arteries are normal or slightly dilated in the early stages, and become thinner in the later stages. The central retinal arterial pressure was reduced, and the intraocular blood flow was completely disappeared by gently pressing the eyeball with fingers. The central arterial pressure measured in both eyes can be 25% to 50% lower than that of healthy eyes.

3. Eye ischemic syndrome

Any reason that affects the blood circulation of the eye can cause ocular ischemic syndrome, including anterior segment ischemia and posterior segment ischemia. Posterior segment ischemia produces hypoperfusion retinopathy, ischemic optic neuropathy, and choroidal lesions. Anterior ischemia is called anterior segment ischemic syndrome.

Ocular ischemic syndrome caused by carotid artery obstruction or stenosis is usually accompanied by bilateral carotid artery disease. Ischemic syndromes can develop unilaterally or bilaterally, but they are usually mild and severe. Depending on the degree of ischemia, symptoms may be gradual or sudden. In addition to changes in the fundus, this syndrome also has signs of anterior segment ischemia, such as conjunctival congestion, edema, corneal epithelium and parenchymal edema, which can form bullae and corneal erosion. Iris ciliary body produces ischemic uveitis, anterior chamber Cells float and flash positive. Localized necrosis of the iris causes pupil deformation. Due to the influence of secreted aqueous humor components, the lens may become cloudy. Long-term chronic ischemia can cause neovascularization of the fundus, iris, and angle of the angle, leading to peripheral anterior adhesion, closing the angle of the angle, forming neovascular glaucoma, and often causing eyeball atrophy.

In addition to the symptoms of the fundus and anterior segment of the carotid artery, patients with carotid artery obstruction or stenosis may also have other ocular symptoms, such as eye and orbital pain, anterior protrusion of the eyeballs, or drooping of the eyelids and pupil dilation when Horner syndrome occurs. Systemic symptoms may include weakening or disappearing of carotid pulsation. Carotid murmurs and brain symptoms such as paroxysmal dizziness and recurrent contralateral hemiplegia, decreased sensory function, temporary speech impairment, and brain in 72% of patients Vascular extraneous or psychiatric symptoms similar to Alzheimer's disease. These patients often have hypertension, coronary heart disease, diabetes or increased blood viscosity and increased blood lipids.

Arterial occlusion or stenosis retinopathy examination

Fluorescence angiography

Both arm-retinal circulation time and retinal circulation time were prolonged. The optic disc is normal or shows strong fluorescence. The macula has leaky flaky fluorescein. Microhemangioma can be seen in the posterior pole and equator. Retinal arteries, veins, small blood vessels, and capillaries can all have fluorescein leakage, and the veins are beaded. In some cases, there can be capillary nonperfusion areas and arteriovenous communication.

2.ERG inspection

The b wave is reduced.

3. Peripheral visual field examination can suggest ipsilateral hemianopia.

4.B ultrasound and CDI

You can understand the diameter and blood flow of the bilateral carotid arteries. Carotid angiography is helpful for diagnosis if necessary, but it is dangerous.

Diagnosis of arterial occlusion or stenosis retinopathy

Diagnosis is not difficult based on medical history, eye examinations, and carotid examinations, such as transient darkening, low-pressure retinopathy, weakened contralateral hemiplegia, carotid pulse, and auscultatory murmurs. However, it should be noted that high-grade carotid stenosis murmur is obvious, and complete occlusion will disappear.

Differential diagnosis of arterial occlusion or stenosis retinopathy

Hypoperfusion retinopathy should be distinguished from the following fundus diseases:

Early diabetic retinopathy

Diabetic retinopathy is mostly in both eyes, and fundus hemorrhage and microhemangioma mostly invade the posterior pole and have elevated blood sugar. Carotid artery obstruction is mostly caused by one eye, and the lesions are often in the middle and peripheral areas.

2. Central retinal vein occlusion

Non-ischemic early fundus lesions are similar, but those with venous obstruction have no decrease in arterial pressure, no reduction in carotid pulsation and murmur, and the fundus hemorrhage will gradually increase.

3. Pulseless fundus lesions

Asthenia can also produce low-pressure retinopathy, but the symptoms are more typical and mostly in both eyes, and can be distinguished by the disappearance of radial artery pulsation.

Arterial occlusion or stenosis retinopathy complications

Optic nerve atrophy, corneal bullae and erosions, and neovascular glaucoma can cause eyeball atrophy.

Arterial occlusion or stenosis retinopathy treatment

According to the degree of internal carotid artery occlusion and treatment at different stages, such as transient dark or mild symptoms, anticoagulants and antiplatelet aggregation agents such as aspirin can be used to some extent. In severe cases, only carotid artery stenosis, or the thrombosis is not long or there is no adhesion or has not progressed to the intracranial segment, can be used for internal carotid endarterectomy to remove a diseased segment of the artery and perform anastomosis, which has certain effects . If new blood vessels and glaucoma have been generated, retinal photocoagulation can be done or trials such as ciliary body freezing or peripheral retinal freezing can be performed.