Retinal Artery Embolisation as a Rare Presentation of Calcific Aortic Stenosis: a case report and literature review

doi:10.21203/rs.3.rs-3131434/v1

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Case Report

Retinal Artery Embolisation as a Rare Presentation of Calcific Aortic Stenosis: a case report and literature review

https://doi.org/10.21203/rs.3.rs-3131434/v1

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Background:

Retinal artery embolism is a serious but uncommon complication of calcific aortic stenosis that is only reported in a few patients.

Case presentation:

This report discusses a case of acute central retinal artery occlusion due to calcified aortic valve disease in a 30-year-old man with an uneventful past medical history. A diagnosis was made following a sudden loss of left eye vision. Clinical examination, ECG, echocardiography, chest CT, and coronary catheterisation have all led to the diagnosis of a calcified aortic valve with a high degree of stenosis. The patient underwent emergent aortic valve replacement with an uneventful postoperative course and no further embolic occurrences.

Conclusion:

The association between cardiovascular diseases and retinal artery occlusion is well-known in the literature. Nonetheless, a limited number of articles have documented the association with calcified aortic stenosis. The present study describes a case of painless total loss of vision in the left eye, which occurred as an infrequent outcome of calcific aortic stenosis in a patient who was 30 years old. This presentation highlights the significance of conducting a comprehensive clinical history during the initial assessment, as accurate diagnosis and comprehension of ocular issues can mitigate the risk of severe systemic complications.

Aortic Stenosis

FFA

Fundus Fluorescein Angiography

Central Retinal Artery Occlusion

CRAO

The condition known as Central Retinal Artery Occlusion (CRAO) involves the blockage of blood flow in the central retinal artery of the eye, which may result in significant damage to the optic nerve and subsequent loss of vision. The occurrence of retinal edoema and pyknosis of ganglion cell nuclei has the potential to lead to severe injury to the optic nerve and retina, ultimately resulting in vision loss. In 1859, the first case of CRAO was described by Von Graefe; it has been recognised as a clinical entity ever since (1). The condition typically manifests at an average age of early 60s and exhibits a prevalence of roughly 1 per 100,000 individuals, with a higher incidence rate observed in males (2, 3). The severity of damage is commonly associated with the degree of retinal edoema, as well as the duration of the injury and the existence of collateral arteries, which also affect retinal recovery (4, 5).

Individuals who suffered from CRAO exhibited a significantly reduced lifespan of 5.5 years in comparison to their non-CRAO counterparts of similar age, whose life expectancy was estimated to be 15.4 years (6).

The ophthalmic artery's initial intraorbital branch, known as the central retinal artery, provides the retina with blood supply. It penetrates the optic nerve through the posterior region of the eye. CRAO is most frequently caused by carotid artery atherosclerosis. Nevertheless, among individuals who are below 40 years old, cardiogenic embolism stands out as the most predominant aetiology (7, 8). The typical manifestation of this condition is characterised by an abrupt onset of painless visual impairment that may be preceded by temporary episodes of visual loss, also known as amaurosis fugax. Patients with CRAO typically report experiencing total loss of vision. However, in instances where the cilioretinal artery is spared, macular sparing may be observed (8). Research has demonstrated that the likelihood of emboli originating from a cardiac source is notably elevated in individuals with a medical history of specific cardiac conditions, such as congenital heart disease, atrial fibrillation, valvular heart disease, and rheumatic heart disease (9). The timely detection and management of emboli or thrombi is crucial to prevent permanent visual impairment and irreversible harm. This may involve dislodgement or lysis interventions. As ischemia progresses, the retina undergoes necrosis, leading to vision loss and a yellow-white opaque appearance. Studies utilising experimental models have revealed that a duration of slightly over 90 minutes of complete central retinal artery occlusion results in irreversible damage to the retina (3).

Calcium emboli in one of the coronary arteries have been theorised to be the origin of the presenting symptoms of calcific aortic stenosis. These emboli are often small and silent if they occlude other arteries. However, the retinal circulation is distinctive in that it is obstructed by calcium microemboli, resulting in vision loss, which may be a sign of calcified aortic stenosis. A few of the reported patients had severe valvular stenosis without any symptoms. Moreover, the correlation between the location of calcification, the degree of valve stenosis, and calcific retinal embolism remains uncertain. Anatomical variability is present in approximately 15% of the population, where the cilioretinal artery plays a significant role in providing collateral circulation to the macula. The manifestations in such cases are generally less severe and the long-term prognosis is more favourable (10).

The clinical assessment commonly reveals unilateral vision loss accompanied by an abnormal afferent pupillary response. Visual acuity may vary only between finger counting and loss of eye perception. The presence of an amaurotic pupil (absence of constriction upon direct illumination) intact consensual light response, and an intact near response have been reported. Typically, extraocular eye movements, anterior chamber examinations, and intraocular pressure are within normal limits. A thorough fundoscopic examination is necessary to confirm the diagnosis of CRAO, and any patient presenting with symptoms concerning CRAO must have a comprehensive exam if there are no contraindications to mydriatic medications. Upon fundoscopic examination, the retina displays a diffuse pallor, accompanied by a central macular spot that exhibits a cherry red hue. The aforementioned location is a consequence of the conserved choroidal circulation that flows beneath the thin fovea (Fig. 1).

In addition, the arterioles may be narrowed or segmented. Among the various types of emboli, calcium emboli exhibit a white appearance, cholesterol emboli (also known as Hollenhorst plaques) display an orange hue, and platelet-fibrin emboli manifest as dull white. However, the visualisation of arteriolar emboli is infrequent (11).

A 30-year-old male with a smoking habit of 7.5 packs per year, regular exercise routine, and a seven-year abstention from alcohol, reported experiencing sudden, painless loss of vision in his left eye. The patient has no known medical history. A diagnosis of left CRAO was established subsequent to an ophthalmological assessment.

The diagnosis of CRAO was confirmed using fundus fluorescein angiography (FFA) (Fig. 2).

Early-phase fluorescein demonstrated the absence of retinal artery filling with the exception for the cilioretinal artery, and a delay in retinal vein filling. To rule out any additional abnormality of the vascular structures, brain magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) were performed, which indicated normal characteristics and a dominant left vertebral artery.

Two weeks prior to the presentation, the patient experienced an episode of an abrupt and widespread chest pain, which radiated to the upper arms, and was not exacerbated by exertion or posture. The pain was resolved spontaneously with no medical intervention, so he didn't seek medical advice. He denied symptoms of dyspnoea, orthopnoea, or syncope and there was no history of fever. The patient's family medical history is notable for the presence of congenital bicuspid aortic valve and coarctation of the aorta, for which his father underwent corrective surgery during his early childhood.

Consequently, it was recommended to undergo a cardiac assessment. The physical examination revealed a harsh systolic ejection murmur of grade III/IV, which was perceptible at the right upper sternal border and extended to the carotid arteries. The patient's ECG exhibited sinus rhythm, left ventricular hypertrophy, and ST segment elevation in chest leads V1-V4. Further, echocardiographic findings indicated the presence of aortic stenosis with a mean pressure gradient of 40mmHg and moderate valve area. However, the exact number of cusps could not be determined due to the significant calcification observed. In addition, the patient exhibited concentric left ventricular hypertrophy measuring 1.9cm, a normal ejection fraction of 60%, a normal aortic root measuring 3.5cm, normal left atrial size and function, and mild mitral valve anterior leaflet prolapse accompanied by trace mitral regurgitation. The computed tomography (CT) scan of the chest showed an enlargement of the ascending aorta measuring 4.3cm and the coronary catheterisation procedure disclosed the presence of ostial right coronary artery (RCA) stenosis. However, the cranial CT scan exhibited no abnormalities.

Following the absence of any subsequent embolic episodes, the medical recommendation was to proceed with an emergency aortic valve replacement. During the surgical procedure, a bicuspid aortic valve was observed to be substantially stenotic and significantly thickened, with massive calcium vegetations. Additionally, a highly friable, granular, calcified region was identified at the inferior margin of the fused raphe between the left and right leaflets (Fig. 3).

A mechanical valve was implanted and the patient's recovery following the surgery was with no notable incidents.

The present case demonstrates an uncommon manifestation of CRAO at a significantly younger age compared to the typical demographic of affected people. The majority of CRAO incidents manifest in individuals beyond their fifth decade of life, which coincided with the onset of clinically significant calcific aortic stenosis. Furthermore, the occurrence of CRAO was one of the initial manifestations of aortic stenosis in his case. The definite diagnosis was made using echocardiography and cardiac catheterization to demonstrate aortic valve stenosis and calcification of a severe nature. The patient had a congenitally bicuspid aortic valve (CBV), a condition that can lead to either normal aortic function over the course of their lifespan or the development of stenosis, regurgitation, or infection. His innate anatomical irregularity left him vulnerable to aortic stenosis, thereby playing a role in the occurrence of CRAO (12).

The identification of a significantly calcified and narrowed aortic valve, along with the detection of a calcium embolus in the retinal artery during an ophthalmologic examination, played a crucial role in the decision of pursuing urgent surgical intervention. Although severe aortic stenosis was observed, the patient was asymptomatic and surgery may not have been considered at the time; however, the presence of retinal artery embolisation was assumed to be an indication for surgical intervention in this instance to prevent possible bilateral vision loss.

Various management strategies for CRAO were proposed. Nevertheless, there is a lack of evidence for the efficacy of any of the suggested options in improving the visual outcome. Moreover, it has been suggested that some therapies may lead to worse results compared to the natural history of the condition. The administration of intravenous tissue plasminogen activator (tPA), a thrombolytic agent that dissolves clots, has been demonstrated to be beneficial in the management of CRAO due to its potential for better visual recovery when given within the initial 4.5 hours of onset. Theoretically, conservative measures such as anterior chamber paracentesis, ocular massage, and the use of IOP lowering eye drops may facilitate the movement of the embolus forward in the arteriole, thereby reducing the extent of retinal involvement. However, it was indicated that conservative treatment results in inferior visual outcomes in comparison to intravenous tPA (13). Regardless of the therapeutic approach employed, prompt intervention for vision restoration should be pursued without delay.

Retinal artery embolisation is a severe and infrequent outcome that may arise from calcific aortic stenosis. It is essential to consider CRAO as a possible indicator of other medical conditions, even though CRAO is not typically the primary manifestation of other diseases. In cases of acute vision loss and heart murmur in younger patients, a thorough examination and investigation should be done, and surgical intervention may be indicated to prevent the recurrence of emboli.

CBV: Congenital bicuspid aortic valve

CRAO: Central retinal artery occlusion

CT: Computed tomography

FFA: Fundus fluorescein angiography

IOP: Intraocular pressure

MRA: Magnetic resonance angiography

MRI: Magnetic resonance imaging

RCA: Right coronary artery

tPA: Tissue plasminogen activator

Acknowledgement

Not applicable

Ethics approval and consent to participate

This study was performed in accordance with the tenets of the Declaration of Helsinki.

Consent for publication

Written informed consent to publish this case report was obtained from the patient.

Data Availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Competing interests

The authors declare that they have no competing interests.

Funding

This study did not receive any funding.

Authors' contributions

RSU, IAH, HM, and AD designed and conducted the study; RSU collected the data; RSU and IAH interpreted the data; RSU, IAH, UJH, HYA, OIO, and AMA drafted the manuscript; IAH revised the manuscript. All authors approved the final version of the manuscript.

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No competing interests reported.

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Retinal Artery Embolisation as a Rare Presentation of Calcific Aortic Stenosis: a case report and literature review

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Background

Case presentation

Discussion and Conclusions

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